Description:[001] The present invention relates to the field of the design and development of micromechanical analysis of injection molded short fiber reinforced composites with novel techniques, methods, devices and apparatus. The invention more particularly relates to a system for simulation, calibration, and validation of injection molded short fiber composites through micromechanical analysis.
BACKGROUND OF THE INVENTION
[002] The following description provides the information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] Further, the approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
[004] Short fiber reinforced composites have gained significant attention in recent years due to their remarkable mechanical properties, lightweight nature, and cost-effectiveness. These materials have been increasingly used in various applications, including automotive, aerospace, electronics, and consumer products. The injection molding process, a widely used manufacturing technique for producing complex-shaped compo- nents, has further enabled the utilization of short fiber composites in numerous applications. However, predicting the mechanical behavior of these materials poses a significant challenge due to the complex interactions between the matrix material, reinforcing fibers, and manufacturing process.
[005] Computer simulations offer an effective way to predict the mechanical properties of short fiber reinforced composite components early in the design phase. By accounting for the composite microstructure, mechanical properties of individual constituents, and the manufacturing process, simulations can provide valuable insights into the performance of the final product. Additionally, simulations can help engineers optimize designs and manufacturing processes, reducing the need for physical testing, which can be time-consuming and expensive.
[006] Accurate prediction of the mechanical properties and performance of short fiber reinforced composite components is essential for optimizing their design and ensuring reliability in service. Traditional material models may not adequately capture the anisotropic behavior and nonlinear deformation characteristics of these materials. As a result, there is a growing need for advanced simulation techniques and methodologies that can accurately model short fiber composites and their interaction with the injection molding process. These techniques should consider the influence of fiber orientation, volume fraction, and aspect ratio on the material’s properties, as well as the effects of bonding agents, fiber breakage, and manufacturing-induced defects.
This research aims to develop a comprehensive framework for the simulation, calibration, and validation of short fiber reinforced composite components produced through injection molding. The framework involves reviewing existing knowledge on short fiber composites, injection molding, micromechanical modeling techniques, and material calibration and homogenization methods. Uniaxial tension tests and fiber orientation characterization are conducted to collect experimental data, which is used to calibrate constituent material properties and homogenize linear elastic and thermal properties using Material Designer. A plasticity model is developed for the nonlinear deformation behavior of short fiber composites. The framework also involves importing fiber orientation tensor, volume fraction, weld lines, and initial stress from injection molding simulation results. A mechanical system is set up to simulate the behavior of the composite component under static load. The accuracy and robustness of the proposed framework are evaluated by comparing simulation results with experimental data and assessing the sensitivity of the results to various input parameters. The scope of this research encompasses the development and application of the proposed framework to a case study involving the mechanical behavior of an electronic component’s plastic casing made from a PA66 resin with 20.
[007] In order to develop the proposed framework, it is crucial to understand the existing research in the field of short fiber reinforced composites. Various aspects of these materials have been explored, including their mechanical properties, manufacturing processes, and the development of micromechanical models. For instance, research by Gupta and Kumar focused on the effect of fiber orientation on the tensile strength of short fiber composites. They concluded that fiber orientation is a critical parameter in determining the mechanical properties of these materials, and the accurate prediction of fiber orientation can lead to a more precise estimation of the material’s performance under load. Park et al. investigated the influence of fiber length on the mechanical and thermal properties of injection molded short fiber composites. They observed that an increase in fiber length led to improvements in both mechanical and thermal properties, suggesting that fiber length is another important factor to consider when designing and analyzing short fiber composites.
[008] The manufacturing process of short fiber composites has a significant impact on their final properties. In particular, injection molding can introduce various defects, such as fiber breakage, weld lines, and void formation. Understanding the relationship between the manufacturing process and the resulting properties is essential for accurate simulations and predictions of short fiber composite behavior.
[009] For example, research conducted by Karger-Kocsis et al. analyzed the effects of injection molding parameters on the mechanical properties and fiber orientation of short fiber composites. Their findings indicated that process parameters such as injection speed, mold temperature, and packing pressure significantly influence the fiber orientation distribution and the resulting mechanical properties of the final product. In another study, Badruddin et al. investigated the influence of the injection molding process on the formation of weld lines in short fiber composites. They found that weld lines could significantly compromise the mechanical properties of the composite and that optimizing the injection molding process could help mitigate this issue.
[010] Micromechanical models have been developed to understand and predict the mechanical behavior of short fiber composites better. One such model, the Mori-Tanaka method, has been widely used to predict the effective elastic properties of short fiber composites. In recent years, researchers have also focused on incorporating the effect of the injection molding process into these micromechanical models. For instance, Verhoef et al. proposed a multiscale modeling approach that combined micromechanical models with injection molding simulations to predict the performance of short fiber composite components more accurately.
[011] One of the challenges in simulating the mechanical behavior of short fiber composites is the accurate prediction of fiber orientation within the material. Research conducted by Kunc and Tucker highlights the difficulties in predicting fiber orientation during the injection molding process and the impact of these predictions on mechanical analysis. To address this issue, recent studies have focused on the integration of injection molding simulations with finite element analysis for accurate prediction of the mechanical performance of short fiber composite components. Zhang et al. demonstrated the effectiveness of this approach by incorporating fiber orientation and volume fraction data from injection molding simulations into structural analyses.
[012] Experimental characterization and calibration of short fiber composites are essential for validating micromechanical models. Bledzki and Gassan discussed various experimental methods, such as tensile and flexural tests, for characterizing the mechanical properties of short fiber composites. In a study conducted by Wei et al., experimental data was used to validate and refine micromechanical models, emphasizing the importance of accurate experimental data for model calibration.
[013] Moreover, the integration of manufacturing simulation data, such as fiber orientation and volume fraction, into structural analysis is crucial for accurate prediction of the mechanical behavior of short fiber composites. As shown by Liu et al., incorporating this data into the mechanical analysis process can significantly improve the accuracy of the predictions.
[014] In addition to accurate fiber orientation prediction and incorporation of manufacturing simulation data, it is also important to address the challenges and limitations in the integration of injection molding simulations with mechanical analysis. Pickett and Loos provided an overview of recent advances and challenges in the injection molding of fiber-reinforced composites. By addressing these challenges, the proposed research aims to develop a comprehensive framework that can accurately predict the mechanical behavior of short fiber composites and contribute to the advancement of knowledge in the field of fiber composite analysis.
[015] In summary, existing research in the field of short fiber composites has made significant advancements in understanding the mechanical properties, manufacturing processes, and micromechanical modeling techniques related to these materials. The proposed research aims to build upon this knowledge by developing a comprehensive framework that integrates material characterization methods, manufacturing process simulations, and mechanical analysis techniques for the accurate prediction of short fiber composite component behavior.
[016] Accordingly, on the basis of aforesaid facts, there remains a need in the prior art to provide a system for simulation, calibration, and validation of injection molded short fiber composites through micromechanical analysis. Therefore, it would be useful and desirable to have a system, method, apparatus and interfaces to meet the above-mentioned needs.

SUMMARY OF THE PRESENT INVENTION
[017] In view of the foregoing disadvantages inherent in the known types of conventional devices, systems, methods and techniques, are now present in the prior art, the present invention provides a system for simulation, calibration, and validation of injection molded short fiber composites through micromechanical analysis, which has all the advantages of the prior art and none of the disadvantages.
[018] It is an object of the present invention, to design a device for a micromechanical analysis of injection molded short fiber reinforced composites, emphasizing the impact of microstructure and manufacturing processes on their mechanical performance. The methodology comprises a three-step procedure: material characterization, importing injection molding simulation results, and setting up the mechanical system. Material Designer is utilized to combine micro-mechanical and phenomenological methods for characterizing the homogenized material properties, while experimental data calibrates and validates the model. A case study investigating the mechanical behavior of an electronic component’s plastic casing under static load is provided, illustrating the integration of the micro-mechanical material response computed through Material Designer with fiber orientations from a third-party injection simulation software. This integrated approach accounts for the anisotropic and orientation-dependent properties of short fiber reinforced composites and is mapped into Ansys Mechanical for analysis. The research offers valuable insights for designing and optimizing injection molded short fiber composite components in various applied polymer science applications, highlighting the significance of considering fiber orientation and microstructure to ensure simulation accuracy.
[019] In this respect, before explaining at least one object of the invention in detail, it is to be understood that the invention is not limited in its application to the details of set of rules and to the arrangements of the various models set forth in the following description or illustrated in the drawings. The invention is capable of other objects and of being practiced and carried out in various ways, according to the need of that industry. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
[020] These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[021] When considering the following thorough explanation of the present invention, it will be easier to understand it and other objects than those mentioned above will become evident. Such description refers to the illustrations in the annex, wherein:
[022] Fig. 1-16 illustrate various schematic and graphical representations for a system for simulation, calibration, and validation of injection molded short fiber composites through micromechanical analysis, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[023] The following sections of this article will provide various embodiments of the current invention with references to the accompanying drawings, whereby the reference numbers utilised in the picture correspond to like elements throughout the description. However, this invention is not limited to the embodiment described here and may be embodied in several other ways. Instead, the embodiment is included to ensure that this disclosure is extensive and complete and that individuals of ordinary skill in the art are properly informed of the extent of the invention. Numerical values and ranges are given for many parts of the implementations discussed in the following thorough discussion. These numbers and ranges are merely to be used as examples and are not meant to restrict the claims' applicability. A variety of materials are also recognised as fitting for certain aspects of the implementations. These materials should only be used as examples and are not meant to restrict the application of the innovation.
[024] In general aspect, the present invention discloses to a system for simulation, calibration, and validation of injection molded short fiber composites through micromechanical analysis. The system of the present invention is now described with reference to accompanying Figure 1 to Figure 16.
Methodology
[025] Simulating the thermo-mechanical behavior of short fiber reinforced composites is challenging for materials engineers. A simulation platform can provide a streamlined workflow, making the process more manageable. The workflow comprises three main parts:
1. Micromechanical Modelling: Utilizing homogenization technology, characterize the macroscopic re- sponse of the composite material.
2. Injection Molding Data: Import injection molding simulation results from other software tools and use the simulation platform to map the model.
3. Mechanical Analysis System: Set up a system for simulating the part.
[026] The building blocks of the workflow are flexible, allowing for adaptation to different needs and more advanced requirements. The workflow is based on the principle that material characterization should be independent of part simulation. Therefore, a sequential homogenization approach is used. The outcome of the microstructure homogenization performed in the Material Designer becomes a regular material stored in the Engineering Data. This homogenized material is later fed into the structural solver without further linking to the microstructural system. Once the homogenization is complete, the resulting material can be used for simulating multiple parts, provided they are made of the same composite material.
Theoretical Analysis
[027] The methodology underlying the workflow consists of several key factors, including the microstructure and the manufacturing process. In the case of injection-molded parts, the manufacturing process results in a complex, locally varying fiber-orientation distribution that significantly affects the mechanical performance of the final part. Since the orientation distribution cannot be directly computed for an entire part, injection molding simulations typically predict its second statistical moment, the so-called (second-order) fiber orientation tensor. Various dedicated software tools exist to perform this type of simulation, with their output being a fiber orientation tensor field defined either at the nodes or the element centroids of the injection molding simulation mesh (which is usually different from the structural mesh).
[028] The fiber orientation tensor affects the composite’s overall anisotropic properties. It is a positive semi- definite symmetric 3 × 3 tensor with trace equal to one. Therefore, it admits a spectral decomposition of the form
where
A = V ∗ D ∗ V T (1)
V is a rotation matrix whose columns represent the principal fiber directions,
D is a diagonal matrix of eigenvalues (sorted in decreasing order) with λ1 + λ2 + λ3 = 1
[029] Moreover, singular values are arranged in descending order, and the corresponding singular vectors are also arranged accordingly. These values have hierarchy of importance λ1 ≥ λ2 ≥ λ3 ≥ 0
In general, the mechanical properties of the homogenized material depend on the full orientation tensor. In the event that the local coordinate system is aligned with the principal fibre directions, the material’s reaction is contingent solely upon the two most significant eigenvalues of the orientation tensor.
Material Characterization
[030] Short fibre reinforced composite materials exhibit anisotropic, orientation-dependent, and nonlinear be- haviour, making their modelling a challenging endeavour. This is made simpler by Material Designer by fusing phenomenological and micromechanical techniques. Through homogenization utilising recognised micro-mechanical techniques, linear elastic and thermal material characteristics of the composite are de- rived. In contrast, a phenomenological model calibrated against experimental data predicts the plastic deformation behavior—yielding and hardening.
Constituent Material Data
[031] The simulation of short fiber reinforced composites necessitates the mechanical and thermal properties of the constituent materials (polymer and fibers). Structural analysis requires elasticity properties and potentially secant coefficients of thermal expansion, particularly when thermal loads are applied. For thermal analysis, thermal conductivity is required.
Experimental Data
[032] The homogenization methods in Material Designer consider fiber and resin constituents’ individual prop- erties and microstructure through fiber aspect ratio and orientation. However, complex factors, such as bonding agents, fiber breakage, and deviations from nominal fiber aspect ratio, can impact material properties. Furthermore, nonlinear deformation behavior varies with the manufacturing process, necessitating experimental data for accurate modeling.
[033] It is recommended to perform uniaxial tension tests on a pair of samples that have been machined from an injection-molded plate, with one sample oriented at 0° and the other at 90° in regard to direction of primary flow as shown in Fig. 1. Tests and specimens must adhere to the ISO 527 or ASTM D638 standard in quasi-static conditions.
Assuming the average second-order fiber orientation tensor in the injection molded plate is known, the fiber orientation field can be obtained through microscopic, computed tomography (CT) scans or injection molding simulation.
Calibration of Constituents
[034] In cases where the exact properties of constituent materials are unknown due to variations from the injec- tion molding process, reverse engineering from experimental data can help to determine these properties. Material Designer allows for the calibration of the Young’s modulus of the matrix material and the aspect ratio of the fibers based on the elastic response of the composite. For Analytical Short Fiber Composite Models, the calibration process involves performing a Constituents Calibration analysis using the exper- imental dataset. In the calibration options, selection of the relevant dataset and specifying the variation range for the matrix material’s Young’s modulus and the fiber aspect ratio is done. Once calibration is complete, the fit quality can be assessed and the computed material properties reviewed in the Results panel.
Homogenization of Linear Elastic and Thermal Properties
[035] Material Designer offers two approaches for computing homogenized properties of short fiber reinforced composites, which have been employed in this work: an analytical approach, which uses the Mori-Tanaka method combined with orientation averaging for rapid computation, and a finite element-based approach for a more accurate and in-depth analysis. In both cases, orthotropic elasticity, thermal expansion, and thermal conductivity properties of the composite were computed based on its microstructure and constituents’ properties. Isotropic thermo-elastic properties of the polymer and fibers, fiber volume fraction, aspect ratio, and orientation were defined In this study, the material properties were computed by selecting Orthotropic as the Type of Anisotropy in the Analysis Settings. A Variable Material Analysis was then added, including at least the two largest eigenvalues of the orientation tensor as parameters. Additional parameters, such as temperature and fiber volume fraction, were also selected. The Short Fiber Wizard was used to simplify the process, guiding the setup of suitable sampling of the parameter space.
Calibration of the Plasticity Model
[036] In the present invention, Material Designer’s phenomenological model was employed to predict the nonlinear defor- mation behavior of short fiber composites. The present model integrates an anisotropic Hill yield criterion that is dependent on orientation with a nonlinear hardening law that is isotropic. Hill Plasticity Curve Fitting for Short Fiber Reinforced Composites. The parameters for this constitutive model were fitted against experimental uniaxial tensile data of the composite obtained earlier.
[037] To calibrate the plasticity model of the short fiber composite, uniaxial test data for the 0° and 90° specimens were used. A Curve Fitting analysis was done. Upon completing the fitting, the fit quality was assessed using the Stress-Strain Chart, and the computed material properties were reviewed.
Importing Injection Molding Simulation Results
[038] Moldex3D, a comprehensive injection molding simulation software, was employed to obtain critical data from the injection molding process. Moldex3D provided accurate and detailed insight into the material behavior and properties within the injection molded part. The data from the Moldex3D result files were imported into a Mechanical system using the Injection Molding Data system. This integration facilitated the transfer of essential information, such as fiber orientation and distribution, to aid in the accurate analysis and simulation of the short fiber composite material’s properties.
Setting Up the Mechanical System
[039] The mechanical system setup for simulating short fiber reinforced composites involved several essential steps, including importing the fiber orientation tensor, importing the fiber volume fraction, and reviewing the results. These steps ensure an accurate representation and analysis of the composite material’s mechanical behavior.
Import the Fiber Orientation Tensor
[040] The fiber orientation tensor is a crucial input in simulating the mechanical behavior of short fiber reinforced composites, as it represents the spatial distribution and orientation of fibers within the material. In this study, the fiber orientation tensor was obtained from Moldex3D injection molding simulation results. The data was imported into the mechanical system, allowing for a more accurate representation of the material’s anisotropic properties and mechanical response under various loading conditions.
Import Fiber Volume Fraction
[041] Another vital input for short fiber reinforced composite simulations is the fiber volume fraction. It represents the proportion of fibers in the composite and has a significant impact on the material’s mechanical properties. In this study, the fiber volume fraction data obtained from Moldex3D simulations was imported into the mechanical system. This data enabled a more precise representation of the composite material’s microstructure and, consequently, a more accurate prediction of its mechanical performance.
Review Results
[042] After importing the fiber orientation tensor and fiber volume fraction data and setting up the mechanical system, the simulation was performed to analyze the short fiber reinforced composite’s mechanical behavior. Upon completion, the results were carefully reviewed to assess the accuracy of the material model and validate the simulation. Key aspects considered included the composite’s stress-strain response, ultimate strength, and failure mechanisms. The results provided valuable insights into the material’s mechanical performance and validated the effectiveness of the employed simulation approach for short fiber reinforced composites.
Simulation
[043] The homogenized thermo-mechanical material properties computed in Material Designer account for the individual properties of the fiber and resin constituents, as well as the microstructure through the fiber aspect ratio and orientation. Several complex factors can impact these material properties: the bonding agents added during injection molding, fiber breakage during the mixing process, deviations from the nom- inal fiber aspect ratio, and the nonlinear deformation behavior of short fiber reinforced composites. These factors vary according to the manufacturing process used, necessitating experimental data for accurate modeling.
[044] To obtain a variable material capable of accurately representing the response of a short fiber composite, the following steps were performed with increasing accuracy:
[045] Nominal material properties were assigned to a model simulating the uniaxial tensile test of three specimens oriented at 0°, 30°, and 90° in regards to direction of primary flow, as defined by the ISO 527 standard. The actual elastic properties of the resin and the fiber aspect ratio were determined by reverse engineering from experimental data to improve the accuracy of the predicted elastic properties. The experimental nonlinear response of the specimens was considered by fitting the parameters of the plasticity model in Material Designer, using data from the 0° and 90° specimens. The experimental stress-strain curve of the 30° specimen was used for subsequent validation.
Import the Injection Molding Simulation Results
[046] The injection molding simulation results were imported into the analysis. The dog-bone specimens, rotated at different angles around the Z direction of the global coordinate system, were modeled using three Static Structural systems.
[047] A fixed support and a displacement of 2.5 mm were applied to the two end faces of the geometry, and the resulting deformation was probed at two vertices in the middle of the specimen as shown in Fig. 2. A reaction force was computed on the face where the displacement boundary condition was applied. A similar setup was applied to the other two Static Structural systems. The output parameters, including the measured stiffnesses, were defined by the probed deformations and reaction force computed from the three different models.
[048] The physical specimens for testing were cut from an injection molded plate at different angles (0, 30, and 90 degrees) in regard to direction of primary flow as shown in Fig 3. The same setup was replicated in Moldex3D to simulate the injection molding process and predict the fiber orientation distribution throughout the plate. The corresponding Mesh File and the Fiber Orientation Tensor File were imported into the analysis, and the geometries were aligned correctly in the coordinate system. The injection molding data was then connected to the Model cells of the three Static Structural systems in the project schematic.
[049] This process allowed for the integration of injection molding simulation results into the analysis of the dog-bone specimens, providing valuable insights into the influence of fiber orientation on the material properties of the short fiber reinforced composites.
Import and Map the Fiber Orientation Tensor in Mechanical
[050] The process of importing and mapping the fiber orientation tensor in Mechanical involved several key steps. First, the imported element orientations were mapped, followed by mapping the imported material fields. The fiber orientations were then visualized as lines in the main view, providing insights into the distribution of fibers in the specimen as shown in Fig 4.
[051] An element-wise plot of the mapped fiber orientation tensor eigenvalues was generated, and the elemental values of the fiber orientation tensor eigenvalue in the loading direction were exported as a text file. The average eigenvalue in the loading direction was computed and used later for calibrating the plasticity model as shown in Fig 5 and Fig 6.
[052] The same operations were performed for the models of the other two specimens, resulting in the mapping of the fiber orientation tensor from the injection simulations. The average orientation tensor eigenvalue in the loading direction for the 90° specimen was also obtained.
Combine the Material Response with the Mapped Injection Simulation Data
[053] The process focused on determining the elastic properties of a composite material using Material Designer. By incorporating the Nylon/Polyamide (PA) 66 resin and short glass fibers as constituent materials, the analysis leveraged homogenization techniques and variable material evaluations to compute the material properties at different parameter sample points. This approach allowed for an accurate representation of the short fiber reinforced composite’s behavior.
Reverse Engineering the Constituents Properties
[054] The process of reverse engineering the constituent properties are performed to accurately represent the specific materials used during manufacturing. Key parameters, including the Young’s Modulus and Poisson’s Ratio of the resin and the fiber aspect ratio, are considered in this optimization process. A Direct Optimization system is employed, with objectives and constraints specified to ensure the elastic moduli of the specimens match the experimental data within specified tolerances. The resulting optimized parameters lead to a better representation of the material properties, allowing for more accurate simulations and predictions.
Calibration of the Plasticity Model Against Experimental Data
[055] The calibration of the plasticity model against experimental data is crucial for obtaining an accurate representation of the nonlinear behavior of the composite material. The Hill Plasticity Curve Fitting tool is employed, taking into account the average orientation tensor eigenvalues in the loading direction of the 0° and 90° specimens as shown in Fig 7. This information refines the model, ensuring it aligns more closely with the actual material properties.
[056] Once the initial calibration is performed, the experimental stress-strain curves of the 0° and 90° specimens are incorporated into the analysis. These data sets are essential for validating the accuracy of the model and ensuring that the simulated results are in line with the observed behavior of the material.
The calibrated stress-strain curves are then compared with the experimental data as shown in Fig 8. By examining the differences between the two sets of curves, any necessary adjustments to the material properties or simulation parameters can be made to improve the model.
[057] After the calibration process is completed and the model is validated against the experimental data, the computed material properties can be exported for use in simulating a different part made of the same composite. This step enables further validation and application of the developed material model, contributing to a comprehensive understanding of the composite material’s behavior under various loading conditions.
Import and Use the Validated Material in a New Model
[058] In this case, the primary focus is on simulating the static load deformation of the top casing of an electronic component as shown in Fig 9 using a fiber orientation tensor imported from an injection molding simulation, combined with a material computed in Material Designer. The case study investigates the mechanical behavior of the plastic casing of an electronic component under static load conditions. The material used is a PA66 resin with 20 % volume of glass fibers as reinforcement.
[059] The homogenized stiffness properties of the glass fiber reinforced plastic are computed using the Material Designer in Ansys Workbench. The appropriate materials are assigned to the Matrix and Fiber, and a Short Fiber Composite homogenization is selected. The function of the material response is parameterized based on the eigenvalues of the fibre orientation tensor, utilising a total of ten sample points. Upon the transfer of the computed variable material, a novel composite material consisting of short fibres has become accessible for examination. The fiber orientation tensor is then imported and mapped onto a part in Ansys Mechanical as shown in Fig 10. The necessary files are imported in Ansys Workbench, and the setup of the Injection Molding Data system is connected to the model of the downstream Static Structural system. The imported fiber orientations are visualized as lines in the main view of Ansys Mechanical.
[060] In the final step, the validated material is imported into a new model. The Imported Material Field is selected in the Mechanical tree, and the Imported Fields options are adjusted in the Mechanical Ribbon bar. The first orientation tensor eigenvalue A11 and A22 as shown in the Fig 11 and Fig 12 is automatically assigned, and the process continues with the import of the material field.
[061] In summary, this research paper presents a practical approach to importing fiber orientation tensors, mapping them onto parts, and combining them with computed material properties. The case study’s results and discussion can offer valuable insights to researchers and industry professionals working with short fiber reinforced composite materials in the context of electronic component design and manufacturing.
[062] A vertical static load is applied to the electronic casing, while its bottom faces are fixed as shown in Fig. 13. After resolving the model using the Mechanical Ribbon bar, the coordinate system of the element is aligned with the principal fibre directions while assembling the finite element model. The computational tool adeptly computes the orientation-specific material characteristics of individual components through the retrieval of the variable material derived from Material Designer.
[063] The analysis provides valuable information about the deformation and equivalent Von Mises stress of the electronic casing. The images of these results reveal critical areas of excessive deformation as shown in Fig 14, which may potentially damage the electronic components housed within the casing. Additionally, regions exhibiting high Von Mises stress as shown in Fig 15 signify possible failure spots where plasticity may localize. The stress in the primary fiber direction can be assessed from a normal stress plot in the solution coordinate system as shown in Fig. 16.
The detailed examination of the stress distribution and deformation results underscores the significance of fiber orientation and material properties in short fiber reinforced composites for various applications, including electronic components. The influence of fiber orientation on the mechanical behavior of the composite material becomes evident through the observed stress distribution patterns and deformation under loading conditions.
[064] In regions where fibers are aligned with the applied load, the material exhibits higher stiffness and strength, thus resisting deformation more effectively. This improved mechanical performance is critical in maintaining the structural integrity of electronic components under various operating conditions. Conversely, areas with unfavorable fiber alignment are more susceptible to deformation and potential failure. The misaligned fibers contribute less to the overall strength and stiffness of the composite material, leading to reduced mechanical performance in these regions. The localized stress concentrations in such areas can result in material failure and, ultimately, the failure of the electronic component itself.
[065] In conclusion, this project highlights the critical need for accurate consideration of fiber orientation and material properties in the design and manufacturing of short fiber reinforced composite components. By addressing these factors, engineers can optimize the performance of composite materials and ensure the reliability and durability of the components in various applications.
Conclusion
[066] This work demonstrates the importance of considering fiber orientation and material properties in the design and manufacturing of short fiber reinforced composite components, specifically for an electronic casing. The comprehensive analysis of deformation, equivalent Von Mises stress, and primary fiber direction stress provided critical insights into the mechanical behavior of the composite material under loading conditions.
[067] The results revealed that fiber alignment plays a significant role in the overall performance of the composite material. Regions with favorable fiber orientation exhibited higher stiffness and strength, effectively resisting deformation and maintaining structural integrity. Conversely, areas with unfavorable fiber alignment were more susceptible to deformation and potential failure, indicating the need for design modifications to avoid localized stress concentrations and material failure.
[068] The incorporation of the fiber orientation tensor in numerical simulations enabled engineers to obtain precise predictions of component behavior under various loading conditions. This approach allowed for design and manufacturing process optimization, ensuring that electronic components meet performance and reliability standards.
[069] The benefits and advantages that the present invention may offer have been discussed above with reference to particular embodiments. These benefits and advantages are not to be interpreted as critical, necessary, or essential features of any or all of the embodiments, nor are they to be read as any elements or constraints that might contribute to their occurring or becoming more evident.
[070] Although specific embodiments have been used to describe the current invention, it should be recognized that these embodiments are merely illustrative and that the invention is not limited to them. The aforementioned embodiments are open to numerous alterations, additions, and improvements. These adaptations, changes, additions, and enhancements are considered to be within the purview of the invention.
, Claims:1. A method for simulating thermo-mechanical behavior of short fiber reinforced composites using a simulation platform, the method comprising:
a) Micromechanical Modelling: utilizing homogenization technology to characterize the macroscopic response of the composite material;
b) Injection Molding Data: importing injection molding simulation results from other software tools, and mapping the model on the simulation platform; and
c) Mechanical Analysis System: setting up a system for simulating the part, wherein the material characterization is independent of part simulation.
2. The method of claim 1, further comprising:
a) Performing a sequential homogenization approach where the outcome of the microstructure homogenization becomes a regular material stored in the Engineering Data;
b) Feeding the homogenized material into the structural solver without further linking to the microstructural system; and
c) Using the homogenized material for simulating multiple parts, provided they are made of the same composite material.
3. The method of claim 1 or 2, wherein the microstructure and the manufacturing process, specifically the complex, locally varying fiber-orientation distribution that significantly affects the mechanical performance of the final part, are considered.
4. The method of any preceding claim, wherein the fiber orientation tensor, a positive semi-definite symmetric 3 × 3 tensor with trace equal to one, affects the composite's overall anisotropic properties.
5. The method of claim 4, wherein the orientation tensor admits a spectral decomposition, with A = V * D * V T, V is a rotation matrix whose columns represent the principal fiber directions, and D is a diagonal matrix of eigenvalues (sorted in decreasing order) with λ1 + λ2 + λ3 = 1.
6. The method of any preceding claim, wherein the mechanical properties of the homogenized material depend on the full orientation tensor, and the material’s reaction is contingent solely upon the two most significant eigenvalues of the orientation tensor when the local coordinate system is aligned with the principal fibre directions.
7. The method of any preceding claim, wherein the homogenization methods in Material Designer consider fiber and resin constituents’ individual properties and microstructure through fiber aspect ratio and orientation, with complex factors like bonding agents, fiber breakage, and deviations from nominal fiber aspect ratio potentially impacting material properties.
8. The method of claim 7, wherein uniaxial tension tests are performed on a pair of samples machined from an injection-molded plate, with one sample oriented at 0° and the other at 90° in regards to direction of primary flow, adhering to the ISO 527 or ASTM D638 standard in quasi-static conditions.
9. The method of claim 8, wherein the fiber orientation field is obtained through microscopic computed tomography (CT) scans or injection molding simulation, assuming the average second-order fiber orientation tensor in the injection molded plate is known.
10. A simulation platform configured to execute the method according to any of claims 1 to 9, providing a streamlined workflow for simulating the thermo-mechanical behavior of short fiber reinforced composites.