Material Insights by Technical Interest

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Insights into the Simulation of Failure of Ductile Plastics

by DatapointLabs6,390 views

Performing simulations that can approximate the material behavior of ductile plastics is daunting. Factors such as nonlinear elasticity, inclusion of volumetric and deviatoric behavior, finding and correctly applying the proper material data to create failure criteria are only a few hurdles. A variety of material models exist, each with numerous settings and varied parameter conversion methods. Combined, these cause a great deal of uncertainty for the FEA user. In previous papers, we delved into material models for both LS-DYNA (MAT089, MAT024, and MAT187) and ABAQUS (*ELASTIC, *PLASTIC) using mid-stage validation as a technique to probe solver accuracy. In this presentation, we summarize our findings on the benefits of this combined approach as a general tool to test and tune simulations for greater reliability.

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AutomotiveHigh Speed TestingMechanicalNonlinear Material ModelsPlasticsPresentationsStructural AnalysisUniversal CrashValidation

Workshop: Testing, Modeling and Validation for Plastics & Rubber Simulation in ANSYS

by DatapointLabs8,015 views

Plastics exhibit non-linear viscoelastic behavior followed by a combination of deviatoric and volumetric plastic deformation until failure. Capturing these phenomena correctly in simulation presents a challenge because of limitations in commonly used material models. We follow an approach where we outline the general behavioral phenomena, then prescribe material models for handling different phases of plastics deformation. Edge cases will then be covered to complete the picture. Topics to be addressed include: Using elasto-plasticity; When to use hyperelasticity; Brittle polymers – filled plastics; Failure modes to consider; Criteria for survival; Choosing materials; Spatial non-isotropy from injection molding; Importance of residual stress; Visco-elastic and creep effects; Strain-rate effects for drop test and crash simulations; Fitting material data to FEA material models; The use of mid-stage validation as a tool to confirm the quality of simulation before use in real-life applications.

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ANSYSDensityHyperelasticInjection MoldingMechanicalPlasticityPlasticsPresentationsRate DependencyRheologyRubbersStructural AnalysisThermalValidationViscoelasticYielding/Failure Analysis

A Mechanism for the Validation of Hyperelastic Materials in ANSYS

by DatapointLabs7,024 views

Hyperelastic material models are complex in nature requiring stress-strain properties in uniaxial, biaxial and shear modes. The data need to be self-consistent in order to fit the commonly used material models. Choosing models and fitting this data to these equations adds additional uncertainty to the process. We present a validation mechanism where, using of a standard validation experiment one can compare results from a simulation and a physical test to obtain a quantified measure of simulation quality. Validated models can be used with greater confidence in the design of real-life components.

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ANSYSHyperelasticMechanicalPapersPresentationsStructural AnalysisValidation

Using Mid-stage Validation to Increase Confidence in Simulation of TPOs

by DatapointLabs6,168 views

Finite element analysis of plastics contains assumptions and uncertainties that can affect simulation accuracy. It is useful to quantify these effects prior to using simulation for real-life applications. A mid-stage validation uses a controlled physical test on a standardized part to compare results from simulation to physical experiment. These validations do not use real-life parts but carefully designed geometries that probe the accuracy of the simulation; the geometries themselves can be tested with boundary conditions that can be simulated correctly. In one study, a quasi-static three-point bending experiment of a standardized parallel ribbed plate is performed and simulated, using Abaqus. A comparison of the strain fields resulting from the complex stress state on the face of the ribs obtained by digital image correlation (DIC) vs. simulation is used to quantify the simulation's fidelity. In a second study, a dynamic dart impact experiment is validated using LS-Dyna probing the multi-axial deformation of a polypropylene until failure.

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AbaqusAutomotiveLS-DYNAMechanicalPlasticsPresentationsStructural AnalysisValidation

Progress on the Validation of Simulation for Ductile Polymers

by Hubert Lobo6,348 views

We will focus on our work related to the testing, modeling and validation of simulation for crash and durability applications, including testing techniques, software tools for material parameter conversion, and the use of a mid-stage validation process that uses standardized experiments to check the accuracy of the simulation prior to use in real-life applications. In addition, we present a short introduction to the Knowmats initiative which seeks to collect posts and links to papers from industry experts as a reference for simulation professionals.

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AutomotiveHigh Speed TestingMechanicalNonlinear Material ModelsPlasticsPresentationsStructural AnalysisUniversal CrashValidation

A Design-Validation-Production Workflow for Aerospace Additive Manufacturing

by DatapointLabs7,120 views

With the advent of 3D printing and additive manufacturing, manufacturing designs previously thought difficult to produce can now be generated quickly and efficiently and without tooling. In the aerospace industry, weight is often tied directly to cost and is thus of great importance to any engineering design. Traditionally, the design process often involves much iteration between the designer and the analyst, where the designer submits a design to the analyst, and then the analyst completes his or her analysis and sends recommendations back to the designer. The process is repeated until a valid design meets the analysis criteria. The design is then handed to the manufacturing team which then may have additional constraints or concerns and iterations can continue. Additive manufacturing coupled with topology optimization allows the design and analysis loops and manufacturing iterations to be reduced significantly or even eliminated. The critical step is to ensure that the part will perform as simulated.

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3D PrintingAerospace and DefenseAltair RADIOSSMetalsResearch PapersStructural AnalysisValidation

Determination and Use of Material Properties for Finite Element Analysis: Book Review

by DatapointLabs9,870 views

This book is intended to be a companion to the NAFEMS book, "An Introduction to the Use of Material Models in FE". It informs Finite Element Analysis users of the manner and methodologies by which materials are tested in order to calibrate material models currently implemented in various FEA programs. While the authors seek first to satisfy the basic material models outlined in the companion book, they make important extensions to FEA used in currently active areas including explicit simulation.

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ANSYSAbaqusAerospace and DefenseAltair RADIOSSAutomotiveBiomedicalBook ReviewBuilding MaterialsCAE Vendor/SupplierConsumer ProductsDIGIMATEnergy and PetroleumFoamsFurnitureHigh Speed TestingHome AppliancesHyperelasticIndustrial GoodsLS-DYNAMSC.DYTRANMSC.MARCMSC.NASTRANMaterial SupplierMechanicalMetalsNX NastranNonlinear Material ModelsPAM-COMFORTPAM-CRASHPackagingPlasticityPlasticsRate DependencyResearch LaboratoryRubbersSIMULIASOLIDWORKSStructural AnalysisViscoelasticYielding/Failure Analysis

Using an Intermediate Validation Step to Increase CAE Confidence

by DatapointLabs7,360 views

Simulations contain assumptions and uncertainties that a designer must evaluate to obtain a measure of accuracy. The assumptions of the product design can be differentiated from the ones for the solver and material model through the use of a mid-stage validation. An open loop validation uses a controlled test on a standardized part to compare results from a simulation to the physical experiment. From the validation, confidence in the material model and solver is gained. In this study, the material properties of a polypropylene are tested to characterize for an *ELASTIC *PLASTIC model in ABAQUS. A validation of a quasi-static three-point bending experiment of a parallel ribbed plate is then performed and simulated. A comparison of the strain fields resulting from the complex stress state on the face of the ribs obtained by digital image correlation (DIC) vs. simulation is used to quantify the simulation's fidelity.

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AbaqusAutomotiveBiomedicalConsumer ProductsFurnitureHome AppliancesMaterial SupplierNonlinear Material ModelsPackagingPlasticityPlasticsResearch PapersStructural AnalysisToys/Sporting GoodsValidation