Datapoint Newsletter: Fall '13, Volume 19.4
DatapointLabs on Inc. 5000 List. New Matereality Compare Module Automates Graphical Comparisons. Headquarters Facility Expands.
Read full postMaterials in simulation
Know your materials
Practical knowledge for simulation professionals who need to understand how material behavior is tested, modeled, and represented in FEA.
Understanding the Role of Material Properties in Simulations, Part 2
We discuss material properties in injection molding simulations, including the definition of property requirements, identification of evaluation parameters, and the role of material properties at each stage of the injection molding process, from mold filling through cooling, post-filling and shrinkage/warpage considerations.
Read full postUse of Digital Image Correlation to Obtain Material Model Parameters for Composites
The development of material parameters for FEA is heavily reliant on precision material data that captures the stress-strain relationship with fidelity. While conventional methods involving UTMs and extensometers are quite adequate for obtaining such data on a number of materials, there are important cases where they have been known to be inadequate. The testing of composites to obtain directional properties remains a complex task because of the difficulty related to measuring these properties in different orientations. Digital Image Correlation (DIC) methods are able to capture the stress-strain relationship all the way to failure. In this paper, we combine DIC and conventional methods to measure directional properties of composites. We exploit the unique capability of DIC to retroactively place virtual strain gauges in areas of critical interest in the test specimen. Utilising an Iosipescu fixture, we measure shear properties of structured composites in a variety of orientations to compute the parameters of an orthotropic linear elastic material model. Model consistency is checked by validation using Abaqus.
Read full postImproved Plasticity and Failure models for Extruded MgProfiles in Crash Simulations
"The Crash Simulation of Magnesium Structures with Finite Element Methods demands the use of suitable material and failure models. An associated plasticity model describing the complex asymmetric yield behaviour in tension and compression of Mg extrusions has been developed during the InMaK-project (Innovative Magnesium Compound Structures for Automobile Frames) supported by the German Federal Ministry for Education and Research (BMBF). Differences to the material model 124 in LS-DYNA are exposed. In order to describe the failure behaviour of Mg extrusions under multiaxial loading in FEM crash simulation this constitutive model has been combined with a fracture model for ductile and shear fracture. The fracture model has been added to the user defined constitutive magnesium model in LS-DYNA. The experimental investigations carried out on model components are compared with numerical derived results. Experimental methods for fracture parameter evaluation are shown and general aspects of metal failure due to fracture as well as different modelling techniques are discussed."
Read full postMaterial Modeling of Soft Material for Non-linear NVH
Abaqus’ Non-linear NVH capability permits the capture of material behavior of rubber seals and bushings, plastic parts and foam inserts which have a significant influence on the simulation. In this presentation, we discuss material calibration procedures for this application.
Read full postBehavior-based Material Model Selection and Calibration of Plastics for Crash Simulation
Many material models are available for crash simulation. However, common models are not designed for plastics. We present best practices developed for adapting common models to plastics, as well as best testing protocols to generate clean, accurate rate-dependent data. In addition, we present a streamlined process to convert raw data to LS-DYNA material cards, and harmonized material datasets that allow the same raw data to be used for other crash and rate-dependent analysis software.
Read full postWhite Paper: Standardized Validation Brings Confidence to 3D Printing
Finite element analysis contains assumptions and uncertainty from a number of sources, which can impact the fidelity of the simulation. This uncertainty is often left untested up to prototyping stages. DatapointLabs’ CAETestbench Validation service was developed to add a mid-stage validation step to a designer’s workflow, to test these simulations before parts are made, in order to build confidence in an engineer’s model beforehand. This validation step is illustrated in a 3D printing application.
Read full postA Simplified Approach to the Simulation of Rubber-like Materials under Dynamic Loading
"The simulation of rubber materials is becoming increasingly important in automotive crashworthiness simulations. Although highly sophisticated material laws are available in LS-DYNA to model rubber parts, the determination of material properties can be non-trivial and time consuming. In many applications, the rubber component is mainly loaded uniaxially at rather high strain rates. In this paper a simplified material model for rubber is presented allowing for a fast generation of input data based on uniaxial static and dynamic test data."
Read full postHandbook for Plastics Analysis
This book covers some of the most significant techniques used in modern analytical technology to characterize plastic and composite materials.
Read full postElongational Viscosity of LDPEs and Polystyrenes using Entrance Loss Data
For two low-density polyethylenes and two polystyrenes, axisymmetric and planar elongational viscosities are estimated using entrance loss data from capillary and slit rheometers, respectively. The elongational viscosity is estimated by optimizing the values of various parameters in the Sarkar–Gupta elongational viscosity model such that the entrance loss predicted by a finite element simulation agrees with the corresponding experimental data. The predicted entrance loss is in good agreement with the experimental data at high flow rates. The difference in the experimental and predicted entrance loss at lower flow rates might have been caused by large error in the experimental data in this range.
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