0001]The present invention, fracture prediction method and apparatus, and to a program, and a recording medium.
BACKGROUND
[0002]In recent years, in the automobile industry, development of a vehicle body structure capable of reducing the impact of the collision has become an issue of urgent. In this case, it is important to absorb the impact energy by the structural member of the vehicle. Main structure to absorb impact energy during collision of the automobile, after forming the member by press forming or the like, there is a structure in which closed roughening the members by spot welding. Spot welds, complex deformation at the time of collision, it is necessary to ensure the strength that can maintain the closed section of the member without also easily broken in the load conditions.
CITATION
Patent Document
[0003]
Patent Document 1: Japanese Patent No. 4150383
Patent Document 2: Japanese Patent No. 4133956
Patent Document 3: Japanese Patent No. 4700559 discloses
Patent Document 4: Japanese Patent No. 4418384 discloses
Patent Document 5: Japanese Patent No. 5370456
Summary of the Invention
Problems that the Invention is to Solve
[0004]
　As a method for measuring the breaking strength of the spot weld, the shear joint type, a cross joint type, tensile test using an L-shaped joint shaped test piece is applied. Shear joint type test, the strength of the case leading to a shear force is mainly applied rupture the specimen, the intensity when the cross joint type tests, an axial force to the test piece reaches the main to join fracture, L-shaped joint type test moment specimen is tested to measure the strength of the case leading to mainly applied fracture. Patent Document 1-4, a method of predicting a fracture of the spot weld in each of the input forms have been studied. Specifically, the spot weld width of the flat surface charge of the input load (hereinafter, the effective width hereinafter) method of predicting the fracture strength of the spot welded portion in consideration of the influence of the structure, such as has been proposed in member . The effective width, for example, in the hat member formed of a plurality of spot welds, the width of the flat surface spot weld in a direction orthogonal to the input load direction charge of the input load, for example, the flange width or adjacent spot spacing It is selected. For hat member, the effective width, material strength, a plate thickness, a fixed value of the nugget diameter and the like is subjected to breaking strength prediction as prediction condition value.
[0005]
　However, for example, when considering a collision deformation in the automotive full vehicle model, joined by various input load to the member, a complicated deformation. The direction of the input load in the middle deformable member is considered to change. 1, the ratio between the nugget diameter d and the effective width W of the member (d / W), is a characteristic diagram showing the relationship between the stress concentration factor alpha. The stress concentration factor alpha, is a value that is inversely proportional to the fracture limit load of the spot weld (load reaching the fracture criterion) is an index for evaluating a fracture limit load. As described above, when considering a collision deformation of a motor vehicle, it is conceivable to change the direction of the input load in the middle deformable member, it is considered that also changes the value of the effective width accordingly. Since the nugget diameter d is substantially constant, with the change in the value of the effective width, as illustrated, the stress concentration factor α is changed. In other words, the breaking limit load is changing. Therefore, with respect to members such as direction changes in input load in the middle variant, when the prediction seek breaking limit load of the effective width as a fixed value, at the timing when the direction is changed in the input load, fracture limit load predicted deviation occurs, it is difficult to perform an accurate fracture prediction in.
[0006]
　The present invention has been made in view of the above problems, for example, in case of a collision deformation prediction of automobile parts on a computer, performs exactly the fracture prediction of a spot welded portion obtained by modeling the spot welding with high precision and to provide a fracture prediction method and apparatus, and program and recording medium can.
Means for Solving the Problems
[0007]
　Fracture prediction method of the present invention, the members are joined by spot welding, a fracture prediction method of the spot weld when to fracture by load is applied to the spot weld. Specifically, in the flat surface on which the spot weld portion is provided in said member, said obtains the direction of the effective width perpendicular to the direction of the load comprises a spot weld, in response to a change in the load direction the effective width that varies calculated for each predetermined time interval, a fracture prediction method for predicting a fracture of the spot welded portion by using the calculated the effective width.
[0008]
　Fracture prediction device of the present invention, the members are joined by spot welding, a fracture prediction device for the spot welds if to fracture by load is applied to the spot weld. Specifically, in the flat surface on which the spot weld portion is provided in said member, said obtains the direction of the effective width perpendicular to the direction of the load comprises a spot weld, in response to a change in the load direction calculation means for calculating the effective width that varies at every predetermined time interval, a fracture prediction device comprising a prediction means for predicting a fracture of the spot welded portion by using the effective width.
[0009]
　Program of the present invention, the members are joined by spot welding, is a program for predicting the fracture of the spot welded portion of the case to fracture by load is applied to the spot weld. Specifically, in the flat surface on which the spot weld portion is provided in said member, said obtains the direction of the effective width perpendicular to the direction of the load comprises a spot weld, in response to a change in the load direction a first step of calculating the effective width that varies at every predetermined time interval, a program for executing a second procedure for predicting fracture of the spot welded portion in a computer by using the effective width.
Effect of the invention
[0010]
　According to the present invention, for example, in case of a collision deformation prediction of automobile parts on a computer, it is possible to fracture prediction of a spot welded portion obtained by modeling the spot welding with high accuracy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011]
[1] Figure 1 is a ratio of the nugget diameter d and the effective width W of the member (d / W), it is a characteristic diagram showing the relationship between the stress concentration factor alpha.
FIG. 2 is a schematic diagram showing a schematic configuration of a fracture prediction device according to the first embodiment.
FIG. 3 is a fracture prediction method according to the first embodiment is a flow diagram illustrating the step order.
[4] FIG. 4, in this embodiment, it is a schematic perspective view of a hat-type member used as a measurement object.
FIG. 5 is a flow diagram illustrating a step S2 of fracture prediction method according to the first embodiment in detail.
[Figure 6A] Figure 6A, in the first embodiment, is a schematic perspective view for explaining a case of applying the elliptical law for the calculation of the effective width.
[Figure 6B] Figure 6B, in the first embodiment, is a schematic plan view for illustrating the case of applying the elliptical law for the calculation of the effective width.
[Figure 7A] Figure 7A, in the first embodiment, is a schematic perspective view for explaining a case of applying the rhombic law for the calculation of the effective width.
[Figure 7B] Figure 7B, in the first embodiment, is a schematic plan view for illustrating the case of applying the rhombic law for the calculation of the effective width.
FIG. 8, in the first embodiment, is a schematic plan view for explaining a case of determining the effective width without using an elliptical law and rhombic law like.
FIG 9A] FIG 9A is a schematic side view showing the condition of the hat member and the three-point bending test was used in Example of the first embodiment.
[FIG. 9B] FIG 9B is a schematic plan view showing the state of the hat member and the three-point bending test was used in Example of the first embodiment.
FIG. 10 is in the embodiment of the first embodiment, a table showing the results summarized the presence or absence of breakage occurrence of each spot weld portion after the three-point bending test.
FIG 11A] FIG 11A is a schematic perspective view of a hat-shaped member for explaining the problems of the prior art.
FIG 11B] FIG 11B is a schematic cross-sectional view of a hat-shaped member for explaining the problems of the prior art.
FIG 12A] FIG 12A is a schematic cross-sectional view of a hat-shaped member for explaining the basic configuration of the second embodiment.
[Figure 12B] Figure 12B is a schematic perspective view of a hat-shaped member for explaining the basic configuration of the second embodiment.
FIG 13A] FIG 13A is a schematic perspective view of a hat-shaped member for explaining the basic configuration of the second embodiment.
FIG 13B] FIG 13B is a schematic cross-sectional view of a hat-shaped member for explaining the basic configuration of the second embodiment.
[Figure 14A] Figure 14A is a schematic perspective view of a hat-shaped member for explaining the basic configuration of the second embodiment.
FIG 14B] FIG 14B is a schematic cross-sectional view of a hat-shaped member for explaining the basic configuration of the second embodiment.
[15] FIG 15 is a schematic diagram showing a schematic configuration of a condition acquisition device according to the second embodiment.
FIG. 16 is a condition acquisition method according to the second embodiment is a flow diagram illustrating the step order.
FIG 17A] FIG 17A is a schematic side view of a hat-type member used in the embodiment of the second embodiment.
[Figure 17B] Figure 17B is a schematic cross-sectional view illustrating a hat-shaped member used in the embodiment of the second embodiment.
FIG 18A] FIG 18A is a schematic side view showing the condition of the hat member and the three-point bending test was used in Example of the second embodiment.
[Figure 18B] Figure 18B is a schematic plan view showing the state of the hat member and the three-point bending test was used in Example of the second embodiment.
FIG. 19 is in the embodiment of the second embodiment, a table showing the results summarized the presence or absence of breakage occurrence of each spot weld portion after the three-point bending test.
[20] FIG 20 is a schematic diagram showing an internal structure of a personal user terminal device.
DESCRIPTION OF THE INVENTION
[0012]
　Hereinafter, fracture prediction method and apparatus, as well as the embodiments of the program, and a recording medium will be described in detail with reference to the drawings.
[0013]
　(First Embodiment)
　In this embodiment, the member joined by spot welding as the measurement object, perform deformation simulation by the finite element method (FEM), to predict the fracture of the spot welded portion of the member.
　Figure 2 is a schematic diagram showing a schematic configuration of a fracture prediction device according to the first embodiment. 3, the fracture prediction method according to the first embodiment is a flow diagram illustrating the step order.
[0014]
　In the present embodiment, as shown in FIG. 4, using a hat-shaped member 10 as the measurement object. Hat type member 10 includes a base material 11 is a hat-shaped cross steel sheet formed into a hat, superposing a base material 12 is planar steel sheet with a flat flange surface 13a of the flange portion 13, the flange portion 13 which is a structural member having a junction with the hat closed cross section by spot welding. The flange surface 13a, the spot-welded portion 14 along the longitudinal direction are formed at equal intervals. Between the distance between adjacent spot welds 14 spot distance, the lateral direction of the width of the flange portion 13 is defined as a flange width.
[0015]
　Fracture prediction device according to the present embodiment, as shown in FIG. 2, predicts the first calculation unit 1 to create a fracture prediction formula of the spot weld, a fracture of the spot weld using a fracture prediction formula created It is constituted by a 2 second calculation unit.
[0016]
　For hat type member 10, to perform a fracture prediction of a spot weld 14, as shown in FIG. 3, first, the user to fracture prediction device for inputting various conditions for the hat-shaped member 10 (step S1). The various conditions, the tensile strength of the material of the hat-shaped member 10, total elongation, the carbon equivalent, Young's modulus, thickness, the nugget diameter of the spot weld, element size, the first width, and a second width.
[0017]
　The first width and the second width is a value used to calculate the effective width in step S2 to be described later. The first width is in the flat surface of the member (flange surface 13a), the distance between the spot welds adjacent the spot weld and this of interest (spot distance). The second width is in the flange surface 13a, and orthogonal to the first width through the spot welds of interest is the length of the virtual line segment with both ends that contact with the edge or ridge of the flat surface. In the present embodiment, the spot distance of the spot-welded portion 14 is first width, the flange width of the flange surface 13a is the second width.
[0018]
　Subsequently, the first calculating unit 1 calculates the effective width using the inputted inter-spot distances and flange width (step S2). Effective width is one of the prediction condition value indicative of fracture prediction, in the present embodiment, the flat surface of the member to the spot welding portion is provided, perpendicular to the direction of the input load including the spot weld is the direction of the width.
[0019]
　Step S2 is composed of steps S11 ~ S13 of FIG. 5.
　In step S11, the first calculation unit 1 obtains the shearing force component or axial force load applied to every moment in the spot weld 14, calculates the resultant force and direction.
　In step S12, the first calculation unit 1, projecting the direction of the load applied to the spot welds 14 on the flange surface 13a. Resultant force calculated in step S11, in order to obtain take any three-dimensional direction to project the loading direction on a surface spot welds are provided.
[0020]
　In step S13, the first calculation unit 1 calculates the effective width in the direction orthogonal to the direction of the load projected onto the flange surface 13a.
　In the present embodiment, the calculation of the effective width, applying the ellipse law to the major axis of one of the spots the distance and flange width, the other as the minor axis. Figure 6A, as shown in FIG. 6B, around the spot weld 14, to create the ellipse equation spot distance is a first width major axis, the flange width is a second width as the minor axis. The first calculation unit 1, the diameter of the direction of the ellipse perpendicular to the direction of the load projected onto the flange surface 13a at the spot welds 14, calculated as effective width.
[0021]
　As a method of calculating the other effective width while the major axis of the spot distance and flange width instead of the elliptical law and the other may be applied rhombus law to the minor axis. Figure 7A, as shown in FIG. 7B, around the spot welds 14, creating a diamond-shaped type spot distance major axis, the flange width as the minor axis. The first calculation unit 1, the line segments intersect at right angles to the direction of the load projected onto the flange surface 13a at the spot welds 14 and rhombus sides the length is calculated as an effective width.
[0022]
　Further, without using the elliptical law and rhombus law. Of spot distance and flange width, it may be selected closer to the direction perpendicular to the input load as effective width. Specifically, as shown in FIG. 8, (eggplant both the 45 ° spot distance direction and flange width direction) bisecting the inter-spot distance direction and the flange width direction perpendicular to spot weld 14 as the origin virtual it is assumed that the boundary line 15. If the direction of the load projected onto the flange surface 13a is close to the distance between spots direction relative to the boundary line 15, the first calculation unit defines a flange width and effective width. On the other hand, if the direction of the load projected onto the flange surface 13a is closer to the flange width direction relative to the boundary line 15, the first calculation unit defines the inter-spot distances and effective width. If the direction of the load projected onto the flange surface 13a coincides with the boundary line 15 defines the predetermined distance between spots or flange width and effective width. Alternatively, in the case of the match, it is conceivable to define the average value of the distance between spots and flange width and effective width. In the example of FIG. 8 shows the case direction of the load is close to the distance between spots direction relative to the boundary line 15.
[0023]
　Subsequently, the first calculating unit 1, the input material strength TS at step S1, the plate thickness t, the nugget diameter D of the spot welding, and by using the effective width W that is calculated in step S2, a fracture prediction formula to create (step S3).
　Specifically, fracture prediction formula in the case of shearing force to the spot weld applied to the
　Lord, Fs = TS · W · t / alpha · · · (1)
　alpha = a / (D / W) b + c
　, where Fs is fracture prediction load, a, b, c are a parameter for fitting the experimental results.
[0024]
　Also, fracture prediction formula in the case of axial force is applied to the primary to the spot
　weld, Fn = (d · D · t + e) · (f · t + g) · (h · TS + i) · (j · C eq + k) · · · (2)
　where, Fn is fracture prediction load, C eq is the carbon equivalent, d, e, f, g , h, i, j, k is a parameter for fitting the experimental results.
[0025]
　Also, fracture prediction formula in the case of moment spot weld applied to the
　Lord, Mf = (l · el · E · D · t 3 + m) · (n · t + o) · (p · D + q) · (r · W + s ) · (u · L + v ) · (y · Me + z) ··· (3)
　where, Mf is fracture prediction moment, el extends all the materials, the Young's modulus of E, member, L is the arm length, Me represents the elements size, l, m, n, o , p, q, r, s, u, v, y, z is a parameter for fitting the experimental results. Arm length and is in the L-shaped joint is defined by the distance of the spot welding center and the longitudinal walls, in the members of this consideration, in the direction of width orthogonal to the effective width calculated in step S2 1 / 2 values, i.e., the 1/2 of the direction parallel to the direction of the width of the load is defined as arm length.
　Incidentally, not necessarily (1), (2), without using the equation (3), it may be any expression that can fit the experimental results.
[0026]
　Subsequently, to predict the fracture of the spot welded portion by using a second calculation unit 2.
　Specifically, the input applied to the spot weld, the shear force S, axial forces A, when the moment M, the values and (1), (2) is the equation consisting of (3) , (4), (5) determines that the generated rupture when satisfied either (6). (S
2 + A 2 ) 0.5 / Fs ≧ 1 · · · 　(4) A / Fn ≧ 1 · · · (5) 　M / Mf ≧ 1 · · · (6)

[0027]
　Collision deformation simulation by a finite element method of the hat-shaped member 10 is each time calculated at predetermined time intervals. Load component acting on the spot weld 14 according to the deformation of the member is also each time calculated at predetermined time intervals. The first calculation unit 1 acquires the effective width in the direction orthogonal to the direction of the load that each time calculated for each predetermined time interval to create a fracture prediction formula, a second calculation portion 2 fracture prediction do.
[0028]
　Specifically, a predetermined time interval, by performing the step S2 described above (steps S11 ~ S13) to calculate the effective width, and executes step S3, using the effective width W calculated in step S2 performing fracture prediction based on fracture prediction formula created. Here, the creation of an elliptical equation in the step S13 is performed only the first step S13, In step S13 in a predetermined time interval, using the elliptic equation created in the first step S13, each time a predetermined time interval calculated effective width corresponding to the direction of the load is calculated.
[0029]
　As described above, according to this embodiment, for example, in case of a collision deformation prediction of automobile parts on a computer, it is possible to fracture prediction of a spot welded portion obtained by modeling the spot welding with high accuracy. Therefore, it is possible to omit the crash test of an actual automobile parts, or significantly reduce the number of crash tests. Moreover, since it is possible to accurately member designed to prevent breakage at the time of collision on a computer, it is possible to contribute to shortening of the significant cost savings, development time.
[0030]
　(Example)
　Hereinafter, the first embodiment described above, based on a comparison between the prior art, the function and effect will be described exert its.
　In this embodiment, as shown in Figures 9A, 9B, height 60 mm, were three-point bending test with a hat-shaped member 100 of width 120 mm. In hat type member 100 is joined with the base material 112 is planar steel and the base metal 111 is hat-shaped cross steel sheet by spot welds 66 points, spot distance is 30 mm, the flange width is 15mm is there. As shown in FIG. 9B, in the hat members 100, A column (A1 ~ A33) the position of each spot weld is defined as B columns (B1 ~ B33).
[0031]
　Material of the hat-shaped member 100 is a tensile strength 1500MPa class steel sheet was produced in both thickness 1.6mm preform 111. At this time, the nugget diameter of the spot welds is 6.3 mm. A hat-shaped member 100 supported by a fixing jig 113 and 114, the distance between supporting points of the fixing jig 113 and 700 mm, the three-point bending test pressing at a stroke of 60mm the impactor 115 R150mm from the base material 112 side went.
[0032]
　It also creates a FEM model simulates the experimental condition, incorporating a program according to the present invention. Successively calculates the load direction applied to the spot welded portion at predetermined time intervals, the effective width in the direction orthogonal to the load direction calculated in elliptical law, to calculate the fracture criteria by using the effective width, the spot welding fracture prediction of parts was carried out. For comparison, the case of fixing the effective width to spot interval as prior art 1, was also fracture prediction for fixed effective width to the flange width as prior art 2.
[0033]
　10, A column is the position of each spot weld (A1 ~ A33), the column B (B1 ~ B33), shows the result of summarizing the presence or absence of breakage occurrence of each spot weld portion after the three-point bending test it is a table. The occurrence or non-occurrence of rupture of the spot weld compared to experimental results for all 66 RBI, it was determined the ratio of the number of strike that correctly predict the fracture occurrence or non-occurrence.
[0034]
　Predictive value in the case of predicting the fracture by the method of the first embodiment was 100%. Is a prior art, predictive value 80.3% of the case of a fixed effective width spot interval, the predictive value for fixed effective width at the flange spacing was 90.9%.
[0035]
　These results, in the prior art, in the case where the effective width and spot separation, when the flange width by it can be seen that variations in fracture prediction accuracy. In contrast, by using the method of the first embodiment, in addition to significantly improved fracture prediction accuracy, due to deformation of the member, stable fracture prediction in response to changes in the load direction applied to the spot welds We were able to confirm that the accuracy can be obtained.
[0036]
　(Second Embodiment)
　In the present embodiment, as in the first embodiment, the member joined by spot welding as the measurement object, perform deformation simulation by the finite element method (FEM), of the member predicting the fracture of the spot weld. In the present embodiment, it can be obtained a second width that is orthogonal first width and therewith for calculating the effective width more accurately. Combined with the first embodiment, the accuracy of fracture prediction is further improved.
[0037]
- basic configuration of the present embodiment -
　First, a description will be given of the basic structure of the condition obtaining method according to the present embodiment.
　In hat type member 20A, FIG. 11A, as shown in FIG. 11B, for example, the base material 103 is disposed on the back side of the base material 101, there is a case where the base material 101, 103 are joined by spot welds 22. In this case, for example, using the technique of Patent Document 5, consider the case of obtaining the distance between the focused spot weld and this closest spot weld as effective width. If attention is paid to the spot welding portion 21a, the spot welds 21 since those joining the base material 101 and 102, a spot weld closest to the spot welding portion 21a and 21b, the spot welding portions 21a, between the 21b the distance d1, should be a first width for calculating the effective width. However, spot weld closest to the spot welds 101a on the surface of the base material 101 because it is 22a, resulting in obtaining the spot welding portions 21a, the distance d2 between 22a as the first width. Spot weld 22a is because it is intended to bond the base material 101 and 103, will be erroneous first width is obtained, it is impossible to perform accurate simulation. That is, if attention is paid only to the distance between the spot welding, differ in element or plane adopts the distance between the spot welding, the correct fracture prediction may not be performed.
[0038]
　(1) In the present embodiment, the members to be joined by spot welding, to obtain the angular difference in the normal direction of the shell element of the base material. Based on the obtained angular difference, classifying each constituent surface of the base metal. Each constituent surface, classifying the spot welds belonging to the construction surface. Then, to get a first width and a second width in the spot welds for each constituent surface, to obtain a valid width by the method described in the first embodiment.
[0039]
　As a first width, adopting the distance between the last belonging to the same constituent surface and the spot welds of interest contact spot weld. As a second width, the width (arrangement plane direction of the structure surface perpendicular to the distance between the focused spot weld and the nearest spot weld is classified by the angle difference in the normal direction of the shell element, It is a flat surface corresponding to a predetermined angular difference in.) to adopt.
[0040]
　Base material in shell elements, spot welds, beam element (bar element), the shell element is modeled by solid elements and the like. A beam element is a solid element with a line segment element with the nodes of the two points, the plane element is a shell element with the nodes of the example 4 points, the nodes of the example 8 points and solid elements. For example, in a model that connects the base material A, B by spot welding, the beam elements with spot welds endpoints a, a b (a side connected to the base material A, b side connected to the base material B) modeling, base material A, B is modeled with shell elements. The end point is the opposite ends of the beam elements a, for each b, the base material to be connected, to get the most recent inter-contact spot weld distance and direction of the flat surface width perpendicular to the distance between the spot welds, the first the width and the second width.
[0041]
　Specific examples of (1) shown in FIGS. 12A and 12B. Here, of the preform 101 to 103 constituting the hat member 20B, it will be described as a base material 101 as an example.
　Each flat surface constituting the surface of the base material 101 (hereinafter, referred to as constituent surface.) Considered. Same effective width obtained for a spot weld formed in the configuration surface, an accurate effective width which is subjected to spot fracture prediction. Therefore, in this embodiment, as shown in FIG. 12A, in order to deal with the base material 101 is separated into each component surface, the base material 101, sequentially calculates the angular difference between the normal direction of the adjacent shell elements, base metal 101 surface of classifying each constituent surface. The angular difference is within the predetermined value, 0 ° ~ 45 ° of about less than a predetermined value defined in the range, for example when it is 15 ° or less, the surface of the base 101 between the corresponding shell element If it is a flat surface I reckon. That is, a plurality of shell elements to which the angular difference is within the predetermined value is assumed to belong to the same constituent surface. Thus, for example, as shown in FIG. 12B, the surface of the base 101, construction plane A is a top plate surface, construction plane is the connecting surface B1, B2, constituent surface C1 which are the vertical wall surface, C2 , construction surfaces D1, D2 are the respective connecting surface are classified into constituent surface E1, E2 is flange surface.
[0042]
　Then, the structure surface A ~ E2, classifies the spot welds belonging to the same constituent surface. In the example of FIG. 12B, the two spot welds 22 structure surface A, constituent surfaces C1, C2 for each of the two spot welds 22, four spot welds 21 each of which is classified the structure surface E1, E2. Then, the classification spot welds as those formed in the same configuration plane, obtains a first width and second width. Thus, it is possible to obtain a precise effective width which is subjected to spot fracture prediction. If the structure surface E1 as an example focusing on the spot welding portions 21a, FIG. 11A, without erroneous distance d2 and a first width as FIG. 11B, the first width correct distance d1 as shown in FIG. 12B It will be acquired as.
[0043]
　(2) In the present embodiment, also be arranged to face the base material the back surface side of the base material to be joined by spot welds to obtain a first width and a second width in the same manner as described above.
[0044]
　Specific examples of (2) shown in FIGS. 13A and 13B. In hat type member 20B, the base material 101 is joined by the base material 102, 103 and spot welds 21, 22 of the rear surface. For the base material 102 and 103 to obtain a first width and a second width in the same manner as the base material 101, to calculate the effective width. Here, among the plurality of base materials constituting the hat member 20B, it will be described as the base material 101 and 102 as an example.
[0045]
　As shown in FIG. 13A, FIG. 13B, paying attention to the spot welding portions 21a, the base material 101 as previously described, the distance d1 is obtained as a first width, is the width direction of the structure surface perpendicular to the distance d1 distance d4 is obtained as the second width. In the base material 102, the angular difference between the direction normal to the shell element, constituent surface thereof is one. A first width of the base material 102, a distance d1 similarly to the distance d3 of the base material 101 is obtained as the first width, the distance is such, the width direction of the structure surface perpendicular to the distance d3 in FIG. 13B d5 There is obtained as the second width. However, in the actual simulation, and the upper limit value of the first width and the second width is set, and a predetermined value smaller than the distance d5 to the second width.
[0046]
　(3) In the present embodiment, a focused spot welds back side of the base material which are joined by a rear surface side of the base material which are joined by spot welds and the focused spot weld closest are identical If, to obtain a first width and a second width for the spot welds of interest.
[0047]
　Specific examples of (3) shown in FIGS. 14A and 14B. In hat type member 20C, the base material 101 is joined by the base material 102, 103, 104 and spot welds 21, 22 of the rear surface. Preform 104 is joined by the configuration surface A and the spot welding portion 23 of the base material 101.
[0048]
　Figure 14A, as shown in FIG. 14B, the constituent surface A of the base material 101 includes two spot welds 22 and two spot welds 23. When not considering the information of the back side of the base material 103 and 104 when acquiring a first width and a second width for the base material 101, the spot weld closest to the focused spot weld 22a is spot-welded portion in 22b without resulting in erroneously determined to be a spot weld 23a. Then, the first width in the arrangement plane A of the base material 101, the distance d6 rather distance d7 is acquired by mistake. The focused spot weld 22a is intended to bond the base material 101 and 103, spot welds nearest to bond the base material 101 and 103 as well because it is 22b, the correct first width is a distance d6 . Spot weld 23a is intended to bond the base material 101 and 104, the distance d7 is first width incorrect.
[0049]
　Therefore, in this embodiment, for the focused spot welds 22a and the closest spot weld 23a, since different from the base material 103 which bonding is a base material 104 for bonding the spot welding portions 22a, a distance d7 is not adopted as a first width. Then, since the closest spot weld 23a which then close to the focused spot weld 22a, which shall have joined is a base material 103 is identical to the base material 103 for bonding the spot welds 22a, adopting distance d6 as the first width. As described above, in this embodiment, even in spot welds belonging to the same constituent surface, taking into account that it may base material is joined to the base material of the structure surface is different, the precise even if such a it is possible to obtain a first width and the second width.
[0050]
- specific configuration condition acquisition apparatus and method -
　Figure 15 is a schematic diagram showing a schematic configuration of a condition acquisition device according to the second embodiment. Figure 16 is a condition acquisition method according to the second embodiment is a flow diagram illustrating the step order.
[0051]
　Condition acquisition device according to the present embodiment, as shown in FIG. 15, the angle difference acquiring section 31 is configured by including constituent face classification unit 32, the weld classification unit 33, and the width acquisition unit 34.
[0052]
　Angle difference acquiring unit 31 for each base material to be joined by spot welding, respectively to obtain the angular difference in the normal direction of the shell element of the base material.
[0053]
　Configuration surface classification unit 32, based on the obtained angular difference, classifying each constituent surface of the surface of the base material.
[0054]
　Weld classification unit 33, for each matrix, to classify the spot welds belonging to the construction surface for each classified constituent surfaces.
[0055]
　Width obtaining unit 34 for each base material to obtain a first width and a second width in the spot welds for each classified constituent surfaces. Here, when the focused spot welds back side of the base material which are joined by a rear surface side of the base material which are joined by spot welds and the focused spot weld closest is the same, attention is acquiring a first width and a second width for the spot weld.
[0056]
　For example a hat-shaped member as an object to be measured, to create an analysis model for performing a simulation by FEM, to obtain the effective width of the analysis model, as shown in FIG. 16, first, the angle difference acquiring section 31 for each preform made up of shell elements being joined by spot welding, respectively to obtain the angular difference in the normal direction of the adjacent shell element of the base material (step S21). Figure 14A, Taking an example FIG. 14B, for each of the preform 101-104, thus to obtain an angular difference in the normal direction of the adjacent shell elements.
[0057]
　Subsequently, construction surface classification unit 32, based on the obtained angular difference, classifying each constituent surface of the surface of the base material (step S22). The angular difference is 0 ° ~ 45 within the range of about ° defined below a predetermined value, for example, if 15 ° or less are classified as the same structure surface. Figure 12A, Taking as an example the base material 101 in FIG. 12B, constituent surface A is a top plate surface, the connecting surface is a construction surface B1, B2, constituent surface C1 is each longitudinal wall, C2, each connecting surface there constituent surface D1, D2, classified into constituent surface E1, E2 is flange surface.
[0058]
　Subsequently, weld classification unit 33, for each matrix, to classify the spot welds belonging to the construction surface for each classified constituent surfaces (step S23). Figure 12A, Taking as an example the base material 101 in FIG. 12B, configured surface in the A and two spot welds 22 two spot welds 23, constituent surface C1, each of the C2 two spot welds 22, configured each of the faces E1, E2 are classified four spot welds 21.
[0059]
　Subsequently, the width acquisition unit 34 for each base material to obtain a first width and a second width in the spot welds for each classified constituent surfaces (step S24). Here, when the focused spot welds back side of the base material which are joined by a rear surface side of the base material which are joined by spot welds and the focused spot weld closest is the same, attention is acquiring a first width and a second width for the spot weld. Taking FIG. 14A, a base material 101 in FIG. 14B as an example, attention is focused on a spot weld 22a. In this case, since the spot welding portion 22a to bond the base material 101 and 103, the width acquisition unit 34, among the spot welds proximate to the spot welding portions 22a in the configuration plane A, as well preform 101 , and acquires the distance d6 between the spot welds 22b joining the 103 as the first width. The width acquisition unit 34 acquires the width perpendicular to the first width in the arrangement surface of the base material 103 facing the construction plane A as the second width.
[0060]
　In this embodiment, after acquiring a first width and a second width for each spot weld of the constituent surface of the base material as described above, in the first embodiment with a first width and a second width the described steps S1, S2 (step S11 ~ S13), executes S3. First calculation unit 1 obtains and the effective width in the direction perpendicular to create a fracture prediction formula to the direction of the load which is each time calculated using a first width and a second width at predetermined time intervals, the calculation portion 2 of 2 performs fracture prediction.
[0061]
　As described above, according to this embodiment, members to be tested, for example, three or more of the base metal, even if made of are joined by spot welding, to calculate the effective width obtained by the first embodiment it is possible to accurately obtain the predetermined width of the member required (first width and second width) because, it is possible to fracture prediction of a spot welded portion obtained by modeling the spot welding more accurately.
[0062]
　(Example)
　Hereinafter, a second embodiment described above, based on a comparison between the prior art, the function and effect will be described exert its.
　A hat-shaped member 200 is used as the object to be measured in the present embodiment FIG. 17A, FIG. 17B. Hat type member 200, and the base material 212 is planar steel plate and base member 211 is a hat-shaped cross-sectional shape steel are joined by spot welding at the flange surface, further reinforcing the steel plate on the back side of the base material 211 there preform 213, 214 are disposed, the base material 211 and the base material 213 and base material 211 and the base material 214 are joined by spot welding. The spot weld that joins the base material 211, 212 and 221. The spot weld that joins the base material 211, 213 and 222. The spot weld that joins the base material 211, 214 and 223. In hat member 200, spot welding distance between the spot welds 221 joining the base material 211 and 212 (e.g., adjacent spot welds 221a, the distance d1 between 221b) than the spot joining the base material 211, 213 spot welding distance between the welds 222 (e.g., spot welds 221a, a distance d2 between 222a) found the following is shorter.
[0063]
　In this embodiment, as shown in FIG. 18A, FIG. 18B, height 60 mm, were three-point bending test with a hat-shaped member 200 of width 120 mm. In hat type member 200, joined at the base material 212 and the spot welds of the 66 points is planar steel back and the base material 211 is a hat-shaped cross steel, the base material as a reinforcing plate on the back side of the base material 211 213 and 214 are joined by spot welds of each 66-point base material 211, the spot distance is 30 mm, the flange width is 15 mm. As shown in FIG. 18B defined in the hat members 200, the spot weld that joins the base material 211 and 212, positions A column (A1 ~ A33) of each spot weld, and column B (B1 ~ B33) doing.
[0064]
　Material of the hat-shaped member 200 is a tensile strength 1500MPa class steel sheet, all of the base 211-214 were prepared in plate thickness 1.6 mm. At this time, the nugget diameter of the spot welds is 6.3 mm. A hat-shaped member 100 supported by a fixing jig 215 and 216, the distance between supporting points of the fixing jig 215 and 216 and 700 mm, the three-point bending test pressing at a stroke of 60mm the impactor 217 R150mm from the base material 212 side went.
[0065]
　It also creates a FEM model simulates the experimental condition, incorporating a program according to the present invention. Successively calculates the load direction applied to the spot welded portion at predetermined time intervals, the effective width in the direction orthogonal to the load direction calculated in elliptical law, to calculate the fracture criteria by using the effective width, spot welds It was of fracture prediction.
[0066]
　In this embodiment, as shown in FIG. 19, the "second embodiment", "first embodiment", "prior art", were examined fracture prediction result by the FEM analysis. In the "first embodiment", the method of the first embodiment described above, the hat-shaped member 200, and obtains the effective width at predetermined time intervals in response to changes in the load direction. The "second embodiment", in addition to the method of the "first embodiment", the method of the second embodiment described above, appropriate in consideration of the structure surface and the base material of the hat-shaped member 200 a set the first width and the second width, and obtain a valid width. The "prior art", without any of the methods of the first and second embodiments are also implemented to fix the effective width to spot interval.
[0067]
　The table in Figure 19, of the preform 211 ~ 214, A column (A1 ~ A33) is the position of each spot weld that joins the base material 211 and 212, the column B (B1 ~ B33), three-point bending It shows the result of summarizing the presence or absence of breakage occurrence of each spot weld portion after the test. The occurrence or non-occurrence of rupture of the spot weld compared to experimental results for all 66 RBI, it was determined the ratio of the number of strike that correctly predict the fracture occurrence or non-occurrence.
[0068]
　Predictive value in the case of predicting the fracture by "second embodiment" was 100%. Predictive value in the case of predicting the fracture by the "first embodiment" was 92.4%. Predictive value in the case of predicting the fracture by the "prior art" was 77.2%.
[0069]
　These results, the hat-shaped member 200 having a base member 211 to 214, fracture prediction accuracy in "prior art" is understood to be low. In contrast, "the first embodiment" the fracture prediction accuracy is improved. However, the "first embodiment", it does not take into account the constituent surface and the base material 213 and 214, FIG. 11A, as described with reference to FIG. 11B, wrong spot welding distance a first width and a second It could be obtained as the width. Specific examples thereof FIG. 17A, as shown in FIG. 17B, when it should be the first width for calculating the effective width of the distance d1, thereby obtains the distance d2 as the first width. That is, in the "first embodiment", not correctly acquired first width and a second width in the spot welds for each constituent surface of the hat-shaped member 200, there is also a spot weld showing incorrect fracture prediction. On the other hand, in the "second embodiment" is accuracy of 100% fracture prediction, it was confirmed that stable fracture prediction accuracy regardless of structure member as an object to be measured is obtained.
[0070]
　(Third Embodiment)
　The function of each component of the fracture prediction device according to the first embodiment described above (the first calculation unit 101 and second calculating means 102 2, etc.), and the second embodiment functions of the components of the condition acquisition device according to (31 to 34, etc. in FIG. 15) can be realized by a program stored in the computer's RAM or ROM or the like is operated. Similarly, the steps of the fracture prediction method according to the first embodiment (steps S2 ~ in FIG 3 S3, etc. steps S11 ~ S13 of FIG. 5), in each step conditions acquisition method according to the second embodiment (FIG. 16 step S21 ~ S24, etc.) can be realized by a program stored in the computer's RAM or ROM or the like is operated. The program and a computer-readable recording medium recording the program are included in the third embodiment.
[0071]
　Specifically, the above program may be recorded in a recording medium such as a CD-ROM, or via various transmission media, it is provided to the computer. As the recording medium for recording the program, in addition to a CD-ROM, using a flexible disk, hard disk, magnetic tape, magneto-optical disk, a nonvolatile memory card or the like. On the other hand, as the transmission medium of the program, it is possible to use a communication medium in a computer network system for supplying program information by propagating as a carrier wave. Here, the computer network, LAN, WAN such as the Internet, a wireless communication network, etc., and the communication medium is a wired line or a wireless line such as an optical fiber.
[0072]
　As the program included in the present embodiment, the function of the first or second embodiment is not the only thing as implemented by executing the supplied program computer. For example, even if the program functions of the first or second embodiment in cooperation with operation to have an OS (operating system) or other application software in the computer can be realized, the program in this embodiment include. Further, also, the program is present when all or part of the processing of the supplied program function of the first or second embodiment is performed by the function expansion board or function expansion unit of the computer can be realized It is included in the form.
[0073]
　In the present embodiment, when predicting the fracture of the spot welded portion at a collision FEM analysis of bonded hat member by spot welding, as a subroutine program LS-DYNA, for example collision analysis software generic, the program of the present invention it is possible to work together. That is, the deformation analysis of members at the time of collision with LS-DYNA, using the program of the present invention to fracture of the spot weld.
[0074]
　For example, Figure 20 is a schematic diagram showing an internal structure of a personal user terminal device. In this FIG. 19, 1200 is a personal computer having a CPU 1201 (PC). PC1200 performs ROM1202 or a hard disk (HD) 1211 stored in, or device control software supplied from the flexible disk drive (FD) 1212. The PC1200 is comprehensively controls devices connected to a system bus 1204.
[0075]
　The PC1200 of CPU 1201, ROM 1202 or a hard disk (HD) 1211 of the stored program instructions in steps S2 ~ S3 in FIG. 3 of the first embodiment (steps S11 ~ S13 of FIG. 5), a diagram of a second embodiment procedures, etc. of steps S21 ~ S24 is achieved in 16.
[0076]
　1203 is a RAM, main memory of CPU1201, and functions as a work area, and the like. 1205 is a keyboard controller (KBC), which controls instruction input from a device such as a keyboard (KB) 1209 and not shown.
[0077]
　1206 is a CRT controller (CRTC), which controls display on a CRT display (CRT) 1210. 1207 is a disk controller (DKC). DKC1207 a boot program, controls a plurality of applications, edit files, user files, a hard disk (HD) 1211 storing network management program and the like, and access to the flexible disk (FD) 1212. Here, the boot program, a start-up program to start the execution of the hardware and software of the personal computer (operation).
[0078]
　1208 is a network interface card (NIC), via the LAN1220, network printer, another network device, or another PC exchange bidirectional data performed.
　Note that personal instead of using the user terminal, may be used given computer or the like which is dedicated to fracture prediction device.
Industrial Applicability
[0079]
　According to the present invention, for example, in case of a collision deformation prediction of automobile parts on a computer, it is possible to perform the fracture prediction of a spot welded portion obtained by modeling the spot welding with high accuracy, the collision in an actual automobile member skip test, or the number of crash tests can be greatly reduced. Moreover, since it is possible to accurately member designed to prevent breakage at the time of collision on a computer, it is possible to contribute to shortening of the significant cost savings, development time.

WE CLAIM

The member joined by spot welding, a fracture prediction method of the spot weld when to fracture by load is applied to the spot weld,
　on a flat surface on which the spot welds of the member is provided, the get the direction of the effective width perpendicular to the direction of the load comprises a spot weld,
calculate the effective width that varies in response to changes in the load at predetermined time intervals,
　calculated the effective width fracture prediction method characterized by predicting the fracture of the spot weld using.
[Requested item 2]
　Claim 1, characterized in that calculated using the effective width, and spot distances between the spot welds adjacent the function of the width in the direction orthogonal to the direction of the spot distance of the flat surface fracture prediction methods.
[Requested item 3]
　It said effective width, the function created first, fracture prediction method according to claim 1 or 2, characterized in that calculated by applying the load of the predetermined time intervals.
[Requested item 4]
　The load was projected on the flat surface, it projected fracture prediction method according to any one of claims 1 to 3, characterized in that to calculate the effective width in the direction perpendicular to the direction of the load.
[Requested item 5]
　The member has a first base material and second base material are bonded by spot welding,
　for each of the first base member and said second base member,
　the normal direction of the angle of the adjacent shell element get the difference,
　on the basis of the angular difference classified by structure surface,
　classifying the spot welds belonging to the construction surface for each of the constituent surface,
　for each of the constituent surface, between said adjacent spot welds of fracture prediction method according to any one of claims 1 to 4, characterized in that for obtaining a distance as first width.
[Requested item 6]
　Fracture prediction method according to claim 5, characterized in that to obtain the width of the structure surface in a direction perpendicular to the first width a second width.
[Requested item 7]
　Said member has a third base member which is joined by the spot welding the first base member,
　wherein the said is bonded to the first base member by the spot welds of interest in the first base member 2 and the base material or the third base member, when said spot welds and the joined by the spot welds nearest second matrix or said third matrix of interest are identical, the focused fracture prediction method according to claim 5 or 6, characterized in that obtaining the first width for the spot weld.
[Requested item 8]
　The member joined by spot welding, a fracture prediction device for the spot welds if to fracture by load is applied to the spot weld,
　on a flat surface on which the spot welds of the member is provided, a valid width in the direction perpendicular to the direction of the load including the spot weld, a calculation means for calculating the effective width that varies in response to changes in the load at predetermined time intervals,
　the effective width prediction means for predicting a fracture of the spot weld using a
　fracture prediction device which comprises a.
[Requested item 9]
　The calculating means, claims wherein the effective width, and wherein the spot distance between the spot welds adjacent to be calculated using the function of the direction of the flat portion width orthogonal to the direction of the spot distance fracture prediction device according to 8.
[Requested item 10]
　Said effective width, the first to the function created, fracture prediction device according to claim 8 or 9, characterized in that calculated by applying the load of the predetermined time intervals.
[Requested item 11]
　The calculating means, the load is projected on the flat surface, according to any one of claims 8 to 10, characterized in that to calculate the effective width in the direction perpendicular to the direction of the projected the load fracture prediction device.
[Requested item 12]
　The member has a first base material and second base material are bonded by spot welding,
　for each of the first base member and said second base member,
　the normal direction of the angle of the adjacent shell element and the angle difference acquiring means for acquiring a difference,
　the structure surface classifying means for classifying for each configuration surface based on the angle difference,
　the weld classification means for classifying the spot welds belonging to the construction surface for each of the constituent surface ,
　for each of the constituent surface, the width obtaining means for obtaining a distance between the spot welds adjacent the first width
　fracture prediction device according to any one of claims 8 to 10, characterized in that it comprises .
[Requested item 13]
　The width obtaining means, fracture prediction device according to claim 12, characterized in that to obtain the width of the structure surface in a direction perpendicular to the first width a second width.
[Requested item 14]
　Said member has a third base member which is joined by the spot welding the first base member,
　the width acquisition unit, the first base member by the spot welds of interest in the first base member and said joined second matrix or said third matrix, in the and the spot welding portion and the joined by the spot welds nearest second matrix or said third matrix the same of interest in some cases, fracture prediction device according to claim 12 or 13, characterized in that obtaining the first width for the spot welds of interest.
[Requested item 15]
　The member joined by spot welding, a program for predicting a fracture of the spot welded portion of the case to fracture by load is applied to the spot weld,
　a flat surface on which the spot welds of the member is provided in the a direction of the effective width perpendicular to the direction of the load, including a spot weld, a first step of calculating the effective width that varies in response to changes in the load at predetermined time intervals,
　a second procedure for predicting the fracture of the spot welded portion by using the effective width
　program for causing a computer to execute the.
[Requested item 16]
　The first procedure, the calculating means calculates the effective width, with a spot distance between the spot welds adjacent the function of the width in the direction perpendicular to the direction of the spot distance of the flat surface program according to claim 15.
[Requested item 17]
　The first procedure, the effective width, the first to the function created, the program of claim 15 or 16, characterized in that calculated by applying the load of the predetermined time intervals.
[Requested item 18]
　The first procedure, the load is projected on the flat surface, to any one of claims 15 to 17, characterized in that to calculate the effective width in the direction perpendicular to the direction of the projected the load program described.
[Requested item 19]
　The member has a first base material and second base material are bonded by spot welding,
　for each of the first base member and said second base member,
　the normal direction of the angle of the adjacent shell element a step of obtaining the difference,
　and procedures for classifying for each configuration surface based on the angle difference,
　a step of classifying the spot welds belonging to the construction surface for each of the constituent surface,
　for each of the constituent surface, adjacent a step of obtaining the distance between the spot welds as first width
　program according to any one of claims 15 to 18, characterized by causing a computer to execute the.
[Requested item 20]
　The program according to claim 19, characterized in that to execute the steps of acquiring a width of the structure surface in a direction perpendicular to the first width a second width to the computer.
[Requested item 21]
　Said member has a third base member which is joined by the spot welding the first base member,
　wherein the said is bonded to the first base member by the spot welds of interest in the first base member 2 and the base material or the third base member, when said spot welds and the joined by the spot welds nearest second matrix or said third matrix of interest are identical, the focused program according to claim 19 or 20, characterized in that obtaining the first width for the spot weld.
[Requested item 22]
　A computer-readable recording medium storing a program according to any one of claims 15-21.