Claims:WE CLAIM:
1. A device for measurement of hogging deflection of sample comprising a base supporting a pole mounted with a frame at free end thereof, wherein the frame holds micrometer for measurement of hogging deflection.

2. A device for measurement of hogging deflection of sample as claimed in claim 1, wherein the base forms platform.

3. A device and a method for measurement of hogging deflection of sample as claimed in claim 1 or 2, wherein the pole constitutes a rectilinear bar.

4. A device and a method for measurement of hogging deflection of sample as claimed in any of the preceding claims, wherein the frame is having substantially L-section constituting a single structure.

5. A device and a method for measurement of hogging deflection of sample as claimed in claim 4, wherein the frame, one leg of which is secured to the pole and other leg is provided to hold the micrometer.

6. A device and a method for measurement of hogging deflection of sample as claimed in claim 4 or 5, wherein the free end of the leg is integrally provided with a holder, inner surface of which confirms to annular section, corresponding to outer surface of the micrometer in contact therewith.

7. A device and a method for measurement of hogging deflection of sample as claimed in any of the preceding claims wherein the micrometer screw gauge includes thimble, spindle and Vernier.

8. A method for measurement of hogging deflection of sample comprising steps of:-

- movement of the device to the sample secured to bending machine,
- rotation of the thimble of micrometer to render the spindle touch center of the specimen,
- recording of initial reading when the spindle touches top surface of the sample,
- moving back of the device,
- bending of the flat sample followed by taking another reading for obtaining the deflection.
, Description:A device and a method for measurement of hogging deflection of sample
FIELD OF INVENTION
[001] This invention relates to a device and a method for measurement of hogging deflection of sample. The sample is particularly thin flat sample. The hogging deflection is implemented to determine the flexural stress experienced by the bent sample.

BACKGROUND/PRIOR ART

[002] Residual stress is defined as the stress that remains in a body that is not being subjected to external forces. Residual stress is caused by forming or processing operations, or by the service environment. Measurement of residual stress is important in predicting service life, analyzing distortion, and determining the reasons for failure.

[003] All stress measurement techniques can be divided into one of two classes, wherein one measures actual strain, and the other measures changes in strain. Residual stress measurement techniques may also be classified by whether the results are qualitative or quantitative. The choice of a method of measurement should be based on the kind of information needed, but economic concerns are frequently the overriding factor. In addition, it is important to recognize the limitations of each technique.

[004] In this study, the technology of XRD is made use for measuring residual stresses in a small rectilinear strip shaped sample. The measurement of residual stress using XRD was driven from the limitations of using strain gauge based techniques i.e. for measuring residual stress in nickel based alloys, the strain gauge required is unique in built and the conventional strain gauge applicable for steels may not be appropriate. In measuring residual stress using X-ray diffraction (XRD), the strain in the crystal lattice is measured and the associated residual stress is determined from the elastic constants assuming a linear elastic distortion of the appropriate crystal lattice plane. Since X-rays impinge over an area on the sample, many grains and crystals contribute to the measurement. The exact number is dependent on the grain size and beam geometry. Although the measurement is considered to be near surface, X-rays do penetrate some distance into the material, in which the penetration depth is dependent on the anode, material and angle of incidence. Hence the measured strain is essentially the average over a few microns depth under the surface of the specimen. When making a residual stress using XRD, the values need to be validated by some means for this particular material. Therefore, a strip sample is taken and a residual stress is induced by bending the sample. This stress induced is measured using XRD, which is compared with the calculated theoretical stress value based on the deflection of the strip sample. Hence, it calculates the flexural stress experienced by the thin flat sample.

Now, reference may be made to the following prior arts.
US3520593A- This is directed to coplanar decoding light beam deflection apparatus. However, this utilizes optical prisms of electrically controllable refractive materials systematically disposed along a common axis so as to provide light beam deflection powers which vary with the geometric progression, for example, 1:2:4:8, or wherein n optical units provide 2. axial alignments of character shaped light beam.
US4589288A- It is related to a non-destructive method and apparatus provided for testing a wood panel, such as a sheet of plywood, to establish values which may be used in calculating a measure of the modulus of elasticity (MOE) for the panel. The invention involves supporting the bottom surface of the panel horizontally with two spaced parallel rollers and contacting the top surface of the panel with a pivotally mounted loading bar which is adapted to apply linear loading to the panel substantially uniformly across its width, even though the panel may be warped or bent. The loading bar is biased by a double-acting cylinder so as to apply a first load and then, in quick succession, a second incremental load. The two loads are selected so as to fall on the substantially linear portion of the load deflection curve for the panel. The magnitudes of the two loads are measured with suitable means, such as a load cell. The extension or distance moved by the cylinder in applying the incremental load is known or measured. With the two loadings and the incremental deflection established, one can calculate, using standard formulae, a value which is found to closely approximate the MOE.

US7302860B1- A panel testing device that includes a frame, a first roller assembly pivotally mounted to the frame including a first roller and a second roller spaced apart from and substantially parallel to the first roller. The panel testing device also includes a second roller assembly pivotally mounted to the frame having a third roller and a fourth roller spaced apart from and substantially parallel to the third roller. The device is configured such that the first and third rollers may be engaged with a first side of a test panel and the second and fourth rollers may be engaged with a second side of the test panel. The first and second roller assemblies are pivoted in opposing directions to bend the panel. A LASER displacement sensor is mounted on a movable manipulator measures the deflection of the panel as the panel is bent.
[005] However, all the aforesaid prior arts are implemented in order to measure sagging deflection with the help of some electronics means. Further, all of them involve sophisticated concept in operation thereof.

[006] In view of the above, it is required to devise a device, which can address issues of known arts. Further, the device can be manually operated and employed for the measurement of hogging deflection.

OBJECTS OF THE INVENTION

[007] The object of the present invention is to provide a device and a method for measurement of hogging deflection of sample which overcomes shortcomings of the prior art(s).

[008] Another object of the present invention is to provide a device for measurement of hogging deflection of sample which is simple in construction.

[009] Still another object of the present invention is to provide a device and a method for measurement of hogging deflection of sample which is cost effective.

[0010] Yet another object of present invention is to provide a device and a method for measurement of hogging deflection of sample which is utilized to determine flexural stress experienced by the specimen.

SUMMARY OF THE INVENTION

[0011] According to the invention, there is provided a device for measurement of hogging deflection of sample comprising a base supporting a pole mounted with a frame at free end thereof, wherein the frame holds micrometer for measurement of hogging deflection.

[0012] The base forms platform. The pole constitutes a rectilinear bar. The frame is having substantially L-section constituting a single structure.

[0013] The frame, one leg of which is secured to the pole and other leg is provided to hold the micrometer.

[0014] The free end of the leg is integrally provided with a holder, inner surface of which confirms to annular section, corresponding to outer surface of the micrometer in contact therewith. The micrometer screw gauge includes thimble, spindle and Vernier.

[0015] Further, there is provided a method for measurement of hogging deflection of sample comprising steps of:-

- movement of the device to the sample secured to bending machine,
- rotation of the thimble of micrometer to render the spindle touch center of the specimen,
- recording of initial reading when the spindle touches top surface of the sample,
- moving back of the device,
- bending of the flat sample followed by taking another reading for obtaining the deflection.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0016] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:-

Fig. 1 shows: Side view of a device for measurement of hogging deflection of sample according to present invention.
Fig. 2 shows: Front view of the device in figure 1 in accordance with the invention.

DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0017] The present invention is directed to a technology pertaining to a device and a method for measurement of hogging deflection of sample. Now, reference may be made to fig. 1 and 2. The device comprises a platform (1) supporting a pole (2). The pole forms a rectilinear bar. The pole is mounted with a frame (3) at free end thereof.

[0018] The frame is substantially having a L-section as shown in figure 1. One leg of the frame is secured to the pole and other leg (3A) of which is provided to hold micrometer (M).

[0019] The free end of the leg (3A) is integrally provided with a holder (3B), inner surface of which confirms to annular section, corresponding to outer surface of the micrometer in contact therewith. The frame constitutes a single structure.

[0020] The micrometer screw gauge includes thimble (4), spindle (5) and Vernier (6) as illustrated in figure 1 and 2.

[0021] Measurement of hogging deflection of a thin flat strip sample is carried out as follows: -

[0022] The assembly as a whole move to the specimen, which is fixed to the bending machine. The assembly is placed in such a way that the spindle just touches the center of the specimen by rotating the thimble of the micrometer. The initial reading in the Vernier is taken at this point.

[0023] The spindle (5) touches the top surface of the sample and the initial reading is recorded. The spindle is retreated back and the assembly is moved back. A bend is given to the thin flat sample and at this point of time another reading needs to be taken for measuring the amount of deflection. The assembly is again moved towards the sample and the reading is taken by rotating the thimble and spindle touching the surface of sample. The assembly is retreated back. The difference between the initial and final reading gives the measure of deflection. It’s made sure that at all instance the platform (1) is kept flat. The procedure is repeated to measure successive deflections.

[0024] Advantageous Features: -

- Manual operation of the fixture without any requirement of any electronic mean
- Portable
- Provides access to calibrate bending phenomena like residual stress induced during bent
- High accuracy of upto 0.01 mm.

[0025] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0026] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims: -