June 09, 2015 | by PolyXtrue | views 4927
The flow in a coat-hanger die is simulated using the axisymmetric and planar elongational viscosities of a low-density polyethylene (LDPE) resin. Elongational viscosity is found to affect the velocity distribution at the die exit. Also, the predicted pressure drop in the die changed significantly when the effect of elongational viscosity was included in the simulation. However, elongational viscosity had only a minor effect on the temperature distribution in the die. Predicted pressure drop is compared with the corresponding experimental data.
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Rheology
Plastics
Extrusion
PolyXtrue
Research Papers
November 09, 2002 | by DatapointLabs | views 4924
There has been a long standing need for a book that describes the
process of injection molding using the insights developed from twenty years of computer aided engineering (CAE). The authors, all veterans of injection molding CAE, have filled this need with their book. "Successful
Injection Molding" is a lot more than a book about injection molding CAE. It is clear at this stage that CAE is a tool, which, if well handled, can provide excellent results. That being said, a successful implementer of CAE for injection molding must have a range of insights into the diverse
idiosyncrasies of this enormously complex manufacturing process. The book is successful in clearly addressing these issues.
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Injection Molding
Book Review
January 19, 2011 | by DatapointLabs | views 4922
We present a methodology for DIGIMAT users to perform the DIGIMAT MX reverse engineering process to obtain material parameter inputs for crash, elasto-plastic, creep and visco-elasticity. The injection-molding process used involves a standardized plaque geometry with fully developed flow, with test specimens taken from a specific plaque location. A standardized testing procedure is applied and the resulting DIGIMAT MX inputs are handled in a streamlined data stream, which saves time and improves the reliability of the reverse engineering process. The DIGIMAT MX reverse engineering itself can be performed as a service in collaboration with e-Xstream. This gives the user a speedy and tightly controlled process for performing complex finite element analysis with filled plastics
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Blow Molding
Extrusion
High Speed Testing
Injection Molding
Nonlinear Material Models
Structural Analysis
DIGIMAT
Presentations
October 14, 2005 | by Paul Du Bois | views 4921
The numerical simulation of structural parts made from plastics is becoming increasingly important nowadays. The fact that almost any structural requirement can be combined in a lightweight, durable and cost effective structure is the driving force behind its widespread application. More and more structural relevant parts are being constructed and manufactured from plastics. This on the other hand drives the demand for reliable and robust methods to design these parts and to predict their structural behaviour. the key ingredients that need to be available are verified, calibrated and validated constitutive models for any family of plastic material. This holds not only true for crashworthiness applications but for any other application field.
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Plastics
Plasticity
Rate Dependency
Yielding/Failure Analysis
Automotive
Nonlinear Material Models
LS-DYNA
July 30, 2015 | by Helmut Gese | views 4917
"In sheet-metal-forming the forming limit curve (FLC) is used for ductile sheets to predict fracture in deep drawing.
However the use of the FLC is limited to linear strain paths. The initial FLC cannot be used in a complex nonlinear
strain history of a deep drawing process or a successive stamp and crash process including a significant change in
strain rate. The CRACH software has been developed to predict the forming limit of sheets for nonlinear strain paths
[1]. It has been validated to predict instability for bilinear strain paths with static loading in the first path and
dynamic loading in the second path for mild steels [2].
As the postprocessing of strain paths from single finite elements in CRACH is not economic for industrial
applications MATFEM initiated a project to couple CRACH directly with FEM-Code LS-DYNA using a userdefined
material model. This allows a prediction of possible failure during the simulation for all elements with
respect to their complete strain history. A special strategy has been developed to include CRACH without extensive
increase in total CPU time. The developed interface to LS-DYNA allows also the implementation of other failure
criteria demanding the history of deformation like for example a tensorial fracture criterion.
In order to test the reliability of the calculated safety factor experimental tests for bilinear strain paths have been
simulated [2]. In this case the experimental and numerical investigations have been made on two-stage forming
processes (static in the 1st stage and both static/dynamic in the 2nd stage) . The static-static case should simulate a
stamping process with bilinear strain path. The static-dynamic case should simulate a successive stamp and crash
process.
The simulation of a complex deep drawing problem including areas with significantly nonlinear strain paths has
been simulated with LS-DYNA/CRACH-coupling. It can be shown that the prediction of CRACH can differ
significantely from a “standard” prediction based on the initial FLC.
The coupling of LS-DYNA and CRACH showed the potential to predict possible fracture in deep drawing and crash
loading at an early design stage and allowed to optimise geometry and material quality to significantly reduce later
problems in real components."
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Mechanical
Metals
Rate Dependency
Yielding/Failure Analysis
Automotive
High Speed Testing
LS-DYNA
Research Papers
November 15, 2017 | by Altair Engineering | views 4899
Simulation uncertainties arise from different assumptions made in model creation. Mid-stage software validations improve confidence and optimize the design of additively manufactured aerospace components.
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Mechanical
Aerospace and Defense
Structural Analysis
Papers
Validation
3D Printing
April 28, 2015 | by Hubert Lobo | views 4897
High strain-rate properties have many applications in the simulation of automotive crash and product drop testing. These properties are difficult to measure. Previously, we described a novel inferential technique for the measurement of the properties of polycarbonate. In this paper, we demonstrate that the technique appears to work for a variety of polymers. We also show that plastics exhibit different kinds of high-strain rate behaviors
Plastics
LS-DYNA
January 19, 2016 | by Matereality | views 4888
The Export to ANSA capability for nonlinear CAE applications is included in Matereality v9. Once your Matereality database has been populated with CAE Material files, you can select the ones appropriate for your analysis and export them to a master material file for ANSA. Then use the ANSA plug-in to import it, and apply the desired material file to your analysis.
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CAE Vendor/Supplier
ANSA
April 14, 2010 | by DatapointLabs | views 4869
Material testing for simulation is about understanding how to best describe a material’s behavior as input for the CAE code. Such testing requires expertise and experience beyond testing performed in a typical test laboratory; while the test instruments may be the same, the knowledge of CAE and experience with diverse materials is increasingly important. FEA software such as ANSYS is being increasingly used for non-linear simulations. We discuss how DatapointLabs' uncommon material expertise helps you avoid problems when the data is being generated these applications.
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Research Papers
July 27, 2015 | by Paul Du Bois | views 4833
"Reliable prediction of the behavior of structures made from polymers is a topic under considerable investigation in
engineering practice. Especially, if the structure is subjected to dynamic loading, constitutive models considering
the mechanical behavior properly are still not available in commercial finite element codes yet. In our paper, we
present a new constitutive law for polymers which recovers important phenomena like necking, crazing, strain rate
dependency, unloading behavior and damage. In particular, different yield surfaces in compression and tension and
strain rate dependent failure, the latter with damage induced erosion, is taken into account. All relevant parameters
are given directly in the input as load curves, i.e. time consuming parameter identification is not necessary. Moreover,
the models by von Mises and Drucker-Prager are included in the description as special cases.
With the present formulation, standard verification test can be simulated successfully: tensile and compression test,
shear test and three point bending tests."
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Mechanical
Plastics
Plasticity
Rate Dependency
Yielding/Failure Analysis
Automotive
High Speed Testing
LS-DYNA
Research Papers
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