February 13, 2014 | by DatapointLabs | views 5780
As part of Cornell University's mechanical engineering curriculum and study of classical beam theory, an aluminium beam is deformed to a specific load. Theoretical strains are calculated at certain points along the beam using beam theory, and then verified by using strain gauges placed at these points on the beam. This experiment is then extended to simulation of the same test setup in simulation software, where strains are analyzed at the same points. Discrepancies between the simulation, theory, and strain gauge results have often plagued the test, especially when incorporating more complex beam design. Through use of digital image correlation (DIC) it is possible to pinpoint some of the problem areas in the beam analysis and provide a better understanding of the localized strains that occur at any point in the deformed beam. The use of DIC provides a full field validation of simulation data, rather than a single spot check that strain gauges can provide. This validation technique helps to eliminate error that is associated with strain gauge placement and the possibility of missing strain hot spots that can arise when analyzing complex deformations or geometries.
...read full post
Plastics
Metals
Aerospace and Defense
Automotive
Biomedical
Building Materials
Consumer Products
Material Supplier
Toys/Sporting Goods
Electonics/Electrical
Industrial Goods
CAE Vendor/Supplier
Mold Maker/Designer
Structural Analysis
ANSYS
Presentations
April 29, 2015 | by Patrick Cunningham | views 5767
This demonstration showing how to analyze plastic parts using finite element analysis was given by Patrick Cunningham at CAE Associates' Accurate FEA of Engineering Plastics seminar, held on October 14, 2014 in Tarrytown, NY.
...read full post
Plastics
Plasticity
Presentations
September 23, 2015 | by DatapointLabs | views 5763
Thermoplastic materials are one of the largest categories of materials to be injection molded. Moisture-sensitive materials can lead to issues in the molding process. Simulation of the injection molding process requires sophisticated and exact material properties to be measured. This presentation discusses the testing required to characterize a thermoplastic material for use in SIGMASOFT, as well as the effects of moisture on viscosity measurement of a moisture-sensitive material. Consequences of basing designs on wet or dry materials are covered. Implementation of material data into the software to produce a successful injection molding simulation simulation is described.
...read full post
Rheology
Plastics
CAE Vendor/Supplier
Injection Molding
Nonlinear Material Models
SIGMASOFT
Presentations
July 27, 2015 | by Paul Du Bois | views 5748
"To assess the problem of containment after a blade-off accident in an aero-engine by numerical
simulation the FAA has instigated a research effort concerning failure prediction in a number of
relevant materials. Aluminium kicked off the program which involved an intensive testing program
providing failure data under different states of stress, different strain rates and different temperatures.
In particular split Hopkinson bars were used to perform dynamic punch tests on plates of different
thicknesses allowing to investigate the transition between different failure modes such as petaling and
plugging. Ballistic impact tests were performed at NASA GRC for the purpose of validation.
This paper focuses on the numerical simulation effort and a comparison with experimental data is
done. The simulations were performed with LS-DYNA and a tabulated version of the Johnson-Cook
material law was developed in order to increase the generality, flexibility and user-friendliness of the
material model."
...read full post
Mechanical
Metals
Yielding/Failure Analysis
Aerospace and Defense
High Speed Testing
LS-DYNA
Research Papers
Validation
July 15, 2003 | by DatapointLabs | views 5742
Assurance of quality in raw materials, control over production, and a basic understanding of criteria for performance all require a sure and complete
knowledge of analytical methods for plastics. The present volume organizes the vast world of plastics analysis into a relatively compact form. A plastics engineer will find familiar territory in such subjects as
rheometry, differential scanning calorimetry, and measurement of thermal properties. Polymer physicists and chemists will be at home with spectroscopic analyses, liquid chromatography, and nuclear magnetic resonance. All these topics and many more are covered in twelve chapters written by an impressive array of experts drawn from industry and academia.
...read full post
Rheology
Thermal
Plastics
Structural Analysis
Book Review
May 15, 2007 | by Datapoint Newsletters | views 5740
Links to Datapoint Newsletters published 1995-2007
...read full post
Newsletters
August 24, 2015 | by Massimo Nutini | views 5735
Glass-fiber-reinforced polypropylene (GF PP) materials are increasingly being used by customers to replace metal and engineering polymers in structural automotive applications. Like all glass-fiber reinforced thermoplastics, GF PP products can show anisotropy caused by fiber orientation that is induced by the injection process. Taking into account fiber orientation in the simulations enables designers to improve the accuracy of the analyses. This can help prevent arbitrary choices and assumptions when setting material parameters, which become mandatory when an isotropic material law is used. The method proposed in this paper takes advantage of the availability within Ls-dyna of an anisotropic material law (MAT_103), which allows simplified modeling to address critical issues. This law was not developed to address the problem discussed here.
Therefore, this paper illustrates a simplified approach. The presence of glass reinforced fibers is taken into account by running a mold-filling analysis, and then transferring the material flow orientation in to the structural simulation as a material angle. The dependence of the material failure strain on the material orientation can be also easily modeled through a user subroutine. Finally, the approach only requires simple material data based on basic tensile tests; the material law parameters are then identified through optimization techniques. Although this approach is based on some simplifying assumptions, its application is quick and can help the designer obtain more accurate results with respect to the traditional isotropic approach. A selection of validation tests is then proposed that show reliable predictions using limited additional computational effort.
...read full post
Mechanical
Plastics
Rate Dependency
Automotive
High Speed Testing
LS-DYNA
Research Papers
July 31, 2015 | by Massimo Nutini | views 5734
Notwithstanding the increasing demand for polymeric materials in an
extraordinary variety of applications, the engineers have often only limited tools suitable for
the design of parts made of polymers, both in terms of mathematical models and reliable
material data, which together constitute the basis for a finite-elements based design.
Within this context, creep modelling constitutes a clear example of the needs for a more
refined approach. An accurate prediction of the creep behaviour of polymers would definitely
lead to a more refined design and thus to a better performance of the polymeric components.
However, a limited number of models is available within the f.e. codes, and when the model
complexity increases, it becomes sometimes difficult fitting the models parameters to the
experimental data.
In order to predict the polymer creep behaviour, this paper proposes a solution based on
artificial neural networks, where the experimental creep curves are used to determine the
parameters of a neural network which is then simply implemented in an Abaqus user
subroutine.
This allows to avoid the implementation of a complex material law and also the difficulties
related to match the experimental data to the model parameters, keeping easily into account
the dependence on stress and temperature.
After a discussion of the selection of the appropriate network and its parameters, an example
of the application of this approach to polyolefins in a simplified test case is presented.
...read full post
Mechanical
Plastics
Automotive
Biomedical
Structural Analysis
Abaqus
Research Papers
Validation
June 12, 2009 | by DatapointLabs | views 5732
Over the past couple of decades, standard test methods and material models have existed for rubber-like materials. These materials were classified under the category of Hyperelastic materials. Well established physical test methods and computational procedures exist for the characterization of the material behavior in tension, compression, shear volumetric response, tear strength etc. However, effective modeling of the fracture behavior of hyperelastic materials using finite element techniques is very challenging. In this paper, we make an attempt to demonstrate the use of such standard test methods and the applicability of such test data for performing finite element analyses of complex nonlinear problems using Abaqus. Our goal is to demonstrate the effective use of standard physical test data to model multi-axial loading situations and fracture of hyperelastic materials through tear tests and indentation test simulations.
...read full post
Rubbers
Material Supplier
Industrial Goods
Nonlinear Material Models
Structural Analysis
Abaqus
Research Papers
July 21, 2010 | by DatapointLabs | views 5730
The limitations of modeling materials for simulation are discussed, including lack of clarity in material model requirements, gaps between the material data and the model to which it will be fitted, issues in obtaining pertinent properties, difficulties in parameter conversion (fitting), and preparation of input files for the software being used. Means to address these limitations are presented, including understanding the model completely, measuring the correct data with precision on the right material, selecting the best model for the data and ensuring the best fit of the model to the data, validating the model against a simple experiment, and following best practices to create an error-free input file.
...read full post
Plastics
Rubbers
Foams
Aerospace and Defense
Automotive
Biomedical
Consumer Products
Material Supplier
Toys/Sporting Goods
Electonics/Electrical
Industrial Goods
Packaging
Home Appliances
Presentations
tweet
share
share