This presentation compares Radioss adhesive material models, LAW36 and LAW59, with the objective of assessing their predictive capabilities for epoxy-based structural adhesives.
This work presents a comparative study of adhesive material models LAW36 and LAW59, in Radioss, with the objective of assessing their predictive capabilities for epoxy-based structural adhesives. The investigation focuses on simulating stress distributions, fracture energies, and failure mechanisms in joints of varying adhesive thicknesses (0.1, 0.2, and 0.5 mm). A comprehensive experimental program supports numerical analysis, including bulk tensile, Thick adherend shear test, and Mode I fracture toughness tests, based on ISO 527-2, ISO 11003-2, and EN 6033 standards, respectively. An additional validation test replicating multi-mode loading conditions is incorporated to establish transferability of the calibrated models to realistic applications. Numerical models employ solid elements for adhesive layers and shell elements for metallic adherends, with mesh refinement in adhesive regions to resolve local stress gradients. Displacement-controlled loading is applied to reproduce tensile and shear conditions, enabling extraction of stress-strain responses, fracture energies, and failure patterns. Model calibration is performed against experimental data using fracture toughness, failure strain, and maximum stress as reference parameters. Comparative evaluation is conducted with quantitative error metrics to assess accuracy and computational cost. The results aim to identify the most reliable adhesive law for joint-level simulations, providing guidance for model selection in structural applications.
Our presentation, “Beyond Standards: Material Testing and Processing for Successful Simulations of Polymeric Materials (LAW76)”, focuses on the Semi-Analytical Model for Polymers (SAMP), a material law developed for simulating complex polymer behavior in industries like automotive and aerospace. SAMP integrates strain-rate dependencies and a damage model for accurate predictions in crash and impact scenarios but faces limitations like slow convergence and the absence of a damage model that incorporates strain-rate and triaxiality dependencies. We emphasize the need to go beyond standardized testing, advocating for tailored tests that better reflect real-world conditions, such as varying strain rates, geometries, and environmental factors. This presentation also details a semi-automated calibration process for SAMP and BIQUAD models using iterative workflows to optimize simulation accuracy for tension, compression, shear, and impact tests. Ultimately, SAMP’s flexibility and predictive accuracy make it a powerful tool, but its successful implementation requires advanced knowledge, customized testing, and careful calibration to ensure stability and reliability in material simulations.
Simulations play a crucial role in engineering and material science, and their success heavily relies on the accuracy of input data. Material testing, data conversion, fitting, and formatting are essential steps in the simulation process. This conference will highlight the importance of material testing requirements that extend beyond ISO and ASTM standards to obtain reliable data for input into various common material models, such as Elastic-Plastic, Hyperelastic, and Rate Dependent models. The complexity of foam materials is shown through a case study of successful validation of polyurethane (PU) foam ball drop impact test using LAW 90. PU foams exhibit high deformation with rate dependency in compressive loading, as well as viscoelastic unloading behavior. Proper handling of input test data and critical settings in simulation setup are crucial for accurate results. The case study will showcase our streamlined approach to successful simulation of foam materials, including challenges and limitations of current 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.
Focus on Validation of Simulation: CAETestBench Validation for crash, additive manufacturing, injection molding, rubber hyperelasticity; Review of NAFEMS publication on V&V.