October 21, 2016 | by DatapointLabs | views 2058
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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Density
Rheology
Thermal
Mechanical
Plastics
Rubbers
Hyperelastic
Visco-elastic
Plasticity
Rate Dependency
Yielding/Failure analysis
Injection Molding
Structural Analysis
ANSYS
Presentations
Validation
October 05, 2016 | by DatapointLabs | views 1787
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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Mechanical
Hyperelastic
Structural Analysis
ANSYS
Papers
Presentations
Validation
October 04, 2016 | by DatapointLabs | views 1706
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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Mechanical
Plastics
Automotive
Structural Analysis
LS-DYNA
Abaqus
Presentations
Validation
July 05, 2016 | by Hubert Lobo | views 1787
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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Mechanical
Plastics
Automotive
High Speed Testing
Nonlinear Material Models
Structural Analysis
Multi-CAE Crash
Presentations
Validation
June 24, 2016 | by Massimo Nutini | views 1968
Topics covered: Damage in mineral filled polypropylene under impact conditions; damage modeling and parameter identification (prior art, LyondellBasell contributions, debate in the CAE community); experimental and numerical validation; next steps
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Mechanical
Plastics
Rate Dependency
Yielding/Failure analysis
Automotive
Material Supplier
High Speed Testing
LS-DYNA
Presentations
June 13, 2016 | by DatapointLabs | views 2218
Quantifying simulation accuracy before running crash simulations could be a helpful confidence building measure. This study continues our development of a mechanism to validate material models for plastics used in modeling high-speed impact. Focusing on models for isotropic materials that include options for rate dependency and failure, we explore other models commonly used for ductile plastics including MAT089 and MAT187.
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Mechanical
Plastics
Rate Dependency
Yielding/Failure analysis
Automotive
Toys/Sporting Goods
Packaging
High Speed Testing
LS-DYNA
Research Papers
Validation
June 07, 2016 | by DatapointLabs | views 2331
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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Metals
Aerospace and Defense
Structural Analysis
RADIOSS
Research Papers
Validation
3D Printing
June 03, 2016 | by DatapointLabs | views 2760
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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Mechanical
Plastics
Rubbers
Foams
Metals
Hyperelastic
Visco-elastic
Plasticity
Rate Dependency
Yielding/Failure analysis
Aerospace and Defense
Automotive
Biomedical
Building Materials
Consumer Products
Energy and Petroleum
Material Supplier
Furniture
Industrial Goods
CAE Vendor/Supplier
Packaging
Home Appliances
Research Laboratory
High Speed Testing
Nonlinear Material Models
Structural Analysis
LS-DYNA
Abaqus
ANSYS
DIGIMAT
SOLIDWORKS
MSC.DYTRAN
MSC.MARC
MSC.NASTRAN
NX Nastran
PAM-COMFORT
PAM-CRASH
RADIOSS
SIMULIA
Book Review
May 24, 2016 | by DatapointLabs | views 2468
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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Plastics
Plasticity
Automotive
Biomedical
Consumer Products
Material Supplier
Toys/Sporting Goods
Furniture
Packaging
Home Appliances
Nonlinear Material Models
Structural Analysis
Abaqus
Research Papers
Validation
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