Material Insights by Material Type

Composites

A Framework for the Calibration and Validation of Multiscale Material Models

Multiscale material models are being increasingly applied for high-level simulation of complex materials, such as continuous reinforced material products (unidirectional and woven product forms). These multiscale material models require input data from a minimum of experimental tests, which are then used to characterize a multiscale material model that can be used in structural simulations within a variety of commercial finite element solvers, including OptiStruct, RADIOSS, Abaqus, and LS-Dyna. Using these models, it is possible is to predict the performance of layups from single layer properties, as well as performance of these composites under complex loadings. We present a framework where the required experimental data are collected, including a process for maintaining traceability and consistency of the experimental data using the Matereality software. Experimental test data are transmitted to the HyperWorks Multiscale Designer software for development of an appropriate multiscale material model. The resulting multiscale material model data is stored within Matereality linked to the source experimental data. Different manufactured layups are tested and compared to simulation in a validation step which provides a measure of the solution accuracy.

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Materials Data Workflow for Simulation of Composites in Transportation Applications

Multi-scale material models are being increasing applied for high level simulation of complex materials such as UD layups, fabric laminate composites, fiber-filled plastics. These models require data inputs from a variety of material tests which are then assembled into models used in the finite element solvers. We present an infrastructure for the digitalization of such information, where the required material data are collected including a process for maintaining traceability and consistency of the source data. Information about the compositional characteristics and processing history are captured. Built-in software modules or external client tools can be used for calibration of material models with the resulting material file linked to the source data. The accuracy of the reduced order model can be checked by running a validation simulation against a physical test. Models can be published and released into a master CAE materials library output where they can be used to model such materials for a variety of target solvers. This process improves the reliability and accuracy of composites simulation.

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Material Modeling and Mold Analysis 

We present a perspective on material modeling as applied to mold analysis requirements. Melt-solid transitions and the case for a unified material model are discussed, along with prediction of post-filling material behavior and shrinkage, and the impact of viscous heating on flow behavior and material degradation.

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Theoretical Development of an Orthotropic Elasto-Plastic Generalized Composite Material Model

The need for accurate material models to simulate the deformation, damage and failure of polymer matrix composites is becoming critical as these materials are gaining increased usage in the aerospace and automotive industries. While there are several composite material models currently available within LS-DYNA, there are several features that have been identified that could improve the predictive capability of a composite model. To address these needs, a combined plasticity and damage model suitable for use with both solid and shell elements is being developed and is being implemented into LS-DYNA as MAT_213. A key feature of the improved material model is the use of tabulated stress-strain data in a variety of coordinate directions to fully define the stress-strain response of the material. To date, the model development efforts have been focused on creating the plasticity portion of the model. The Tsai-Wu development efforts have focused on creating the plasticity portion of the model. The Tsai-Wu composite failure model has been generalized and extended to a strain-hardening based orthotropic material model with a non-associative flow rule. The coefficients of the yield function, and the stresses to be used in both the yield function and the flow rule are computed based on the input stress-strain curves using the effective plastic strain as the tracking variable. The coefficients in the flow rule are computed based on the obtained stress-strain data. The developed material model is suitable for implementation within LS-DYNA for use in analyzing the nonlinear response of polymer composites.

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Material Parameter Calibration Services for Abaqus Non-Linear Material Models

DatapointLabs' TestPaks (material testing + model calibration + Abaqus input decks) for rate-dependent, hyperelastic, viscoelastic, NVH, and the use of Abaqus CAE Modeler to transform raw data into material cards will be presented. A representative from Idiada will present a case study explaining the use of DatapointLabs’ material data and TestPaks for simulation.

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Software for Creating LS-DYNA Material Model Parameters from Test Data 

LS-DYNA software contains a wealth of material models that allow for the simulation of transient phenomena. The Matereality® CAE Modeler is a generalized pre-processor software used to convert material property data into material parameters for different material models used in CAE. In a continuation of previously presented work, we discuss the extension of the CAE Modeler software to commonly used material models beyond MAT_024. Software enhancements include advanced point picking to perform extrapolations beyond the tested data, as well as the ability to fine-tune the material models while scrutinizing the trends shown in the underlying raw data. Advanced modeling features include the ability to tune the rate dependency as well as the initial response. Additional material models that are quite complex and difficult to calibrate are supported, including those for hyperelastic and viscoelastic behavior. As before, the written material cards are directly readable into the LS-DYNA software, but now they can also be stored and catalogued in a material card library for later reuse.

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