The changes are primarily just bug fixes. The items are arranged by category. Understand that in many cases, a particular item could fall under more than one category, but in the interest of brevity, each item is listed only once, under a single category.
Excluding the "Miscellaneous" category, the categories are arranged alphabetically. JT Joule Thomson effect is a thermodynamic, isenthalpic process that will occur due to gas expansion through a valve.
For gases with negative JT coefficient, gas after expansion will contain higher energy and produce higher airbag pressure than from the constant enthalpy assumption.
The effect was considered in CPM particle method and now, the effect is included after switching from particle to CV mode. New feature allows heat transfer between particles and inflator material.Modeling of composites in LS-DYNA. Video tutorial (incomplete)
The heat loss from the gas will give a weaker jet impulse. The initial part temperature is the same as the resident gas temperature. The feature is turned on when the target part's specific heat Cp is given. Fix segmentation fault caused by dynamic rebalancing algorithm when only a few active particles exist in particle blast.
For the 3D Navier-Stokes equations solver, add a stability strategy positivity preserving to make it more stable. Complete the positivity-preserving mechanism in the 2D axisymmetric Euler and Navier-Stokes equations solvers. For the CESE moving mesh conjugate heat transfer solvers, fix several bugs that caused these solvers to fail completely. Also, in MPP, a number of bugs related to the mesh decomposition were fixed.
Doing FSI with the chemistry solver for the Euler equations is made more robust by correcting some memory issues, and increasing the number of allowed chemical species. Develop and calibrate new inflator models, especially for KSS, where the calibration was done with experimental data. It was outputting wrong numbers. A blunder caused the ties to fail due to zero penalty forces. Jobs were error terminating in the first cycle. This combination was resulting in an error termination in the input phase.
When the death time is reached, the ties are released. The problem occcured when selective mass scaling was applied to the nodes that are tied. Prior to the fix, kinematic constraints were failing. Fix a memory error during initialization in 2D automatic contact in the case where there are both 2D continuum elements with element failure included and 2D shell elements. Prior to R A bug caused either wrong results or a segmentation fault.
Curve interpolation was using the wrong segment of the curve. Enhance explicit's use of inertia relief by adding a second orthogonalization step for the accelerations. This has not worked until now because we searched for shells to thin through the tied contact, and tied contact is not needed when nodes are shared. Fix bug in calculation of drilling energy calculated for triangular shells and written as hourglass energy in implicit.When modeling low-density foams, it is important to consider potential failure under tensile loading.
The Elastic Modulus Emax in tension is computed to be the max max slope of the…. December 14, by Suri Bala. Here are the three pages of the keyword manual. October 20, by Suri Bala. Finding a good material law can sometimes be a daunting task even for experienced users. Please send any feedback you may have at info…. October 5, by Suri Bala. The default material axes may…. Deformable spotwelds modeled using beams or solids elements can invariably limit the global timestep due to its small dimensions.
When DT2MS is non-zero usually a negative numberthe density of the spotwelds are modified…. April 5, by Suri Bala. To reduce or eliminate the noise in the evaulation of the new yield stress as a function of strain and strain-rate, LS-DYNA offers….
January 17, by Suri Bala. Came across this excellent tutorial that talks in detail the steps involved in determining the Prony series constants.
October 3, by Suri Bala. They are graphically depicted below these figures may appear in the next release of the LS-DYNA keyword and theory manual. April 23, by Suri Bala. LS-DYNA allows several ways to model of stress relaxation often seen in viscoelastic materials when subjected to a sudden constant strain. The methods to model the stress relaxation is briefly discussed here. April 16, by Suri Bala. Honeycomb cell structures are popular among weight conscious designers due to their high strength to weight ratio.
In the automotive space, aluminum based honeycomb structures are widely used to represent barriers to simulate a controlled energy absorption. Honeycomb structures are highly anisotropic and requires adequate testing to characterize them.
This post focusses on the characterization…. March 8, by Suri Bala. Tensile failure in Low Density Foams When modeling low-density foams, it is important to consider potential failure under tensile loading.
Determining Prony Series Constants for Modeling Creep and Relaxation Came across this excellent tutorial that talks in detail the steps involved in determining the Prony series constants.
Stress Relaxation in Viscoelastic Material Models LS-DYNA allows several ways to model of stress relaxation often seen in viscoelastic materials when subjected to a sudden constant strain.Skip to content. Skip to navigation.
Herein are summarized most of the new features, enhancements, and significant corrections made since the release of version R7. These notes are arranged by topic. Understand that in many cases, a particular note may have applicability to multiple topics, but in the interest of brevity, each note is listed only once and under only one topic heading. Press Releases. Meet Dynamore. FEA News. Release Notes. Release notes for Version R7. The input parameters MU and A were converted correctly but the pre-converted values were written to the dyna.
Contact MPP tied contact initialization: Change a tolerance in groupable tied contact bucketsort to match the non-groupable code, and fix the slave node thickness used for beam nodes during initial search in non-groupable contact to match groupable contact. MPP eroding contact: Fix problem of every processor participating in every eroding contact, even if they had none of the nodes or elements.
This caused scaling issues. Fix for MPP contact force summation as applied to shells with compressive thickness behavior. Various fixes to intfor output for MPP contact. MPP tied contact with adaptivity: if any master segments get adapted, we were dropping any slave nodes.
Now flag these, and do a bucketsort for just these nodes, to find their new tied location. This allows tied contacts to work across adaptive steps. Nodes involved in both are removed from the linking interface, but this was leaving some internal structures out of sync, sometimes causing nodes to be moved improperly.
MPP eroding contact: fix long standing bug that might have improperly excluded some nodes from contact. Fix for MPP two sided force transducers with erosion: shared nodes were only flagged on one processor, so some forces along processor boundaries might not have been counted to a force transducer. Fix for MPP groupable contact and implicit when there are both constraint and penalty contact types.
Affects SMP only. Fix a 2D automatic contact bug that occurred if a segment has zero length. Fix an error in 2D automatic contact sliding interface energy reported in glstat.
The outputted value was about 2x the correct value. Fix an MPP 2-surface force transducer blunder when segment based contact is used. The symptom observed was a change in bucket sort behavior making the contact less reliable for contact bewteen segments that are not on the same MPP partition when 2-surface force transducers were used.
Fix a full deck restart error with SMP segment based contact.Skip to content. Skip to navigation. All conference papers can be found on www.
Modeling Metallic Materials
Download the agenda as PDF here. FE approach to evaluate the dynamic friction coefficient for the transient phase of rubber-ice sliding interaction R. Leonardi, S. As well as the core tools for model creation and checking. This workshop will introduce these tools and demonstrate how to use them. Examples include:. Chandrasekaran, M. Burbulla Dr. Kaulich, S. Hanson GNS. Fokylidis, V. Tunc, H. Wuestner Ford-Werke ; N. Pasligh Ford Forschungszentrum Aachen ; C.
Ping, M. Ng Ford Australia. Song BMW. Seats are moved easily to the desired position and dummies are positioned on them, achieving a penetration free and restrained, by seatbelts, system. Pedestrian analysts have at their disposal a complete tool for marking, bulk positioning and loadcase creation for all desired targets and post processing capabilities for the evaluation of the corresponding results.
All interior safety regulations available in the market are applicable in ANSA and META through automated tools for the safety of the driver and passengers. Moncayo Daimler ; M. Cyperling Mercedes-Benz Werk ; G. Dumitru, T.Skip to content. Skip to navigation.
However, a profound understanding of the adopted material model is crucial for obtaining reasonable and reliable FE simulation results. The aim of this class is to give practical guidelines about the application of the most commonly used material formulations.
The focus will be especially on the underlying basic theory as well as on the assumptions made for the corresponding material formulations. Moreover, besides the practical information about particular input formats and the relevance of special settings, the algorithmic background of the various models will also be highlighted.
Finally, diverse applications for the most commonly used metallic material models in LS-DYNA will be illustrated with the help of simple examples. Spezialgebiete: Materialmodellierung, Umformsimulation, Verbindungstechnik Studium: Bauingenieurwesen. Maik Schenke. Carina Sieber. General Information and Cancellation Terms. Hotels and Arrival. Filipe Andrade Dr. Spezialgebiete: Materialmodellierung, FE-Theorie.
Failure Testing Under In-Plane Biaxial Tension and Out-of-Plane Compression
The downstream pressure should use the slave chamber pressure for evaluating the venting from the master bag. The bug produced erroneous internal energy increase. This was likely an issue only if more than one blast was simultaneously in use.
For all immersed-boundary CESE solvers, corrected the plotting of the Schlieren number and the chemical species mass fractions. Brought in enthalpy-related corrections to the CESE chemistry solvers. Enabled output of the timing information for the CESE chemistry solvers. Fixed an issue with opening some LSDA-based chemistry results files.
Applies to SMP only. Nodal coordinates were being changed. This problem existed in R9. The consequence was to sometimes choose the wrong part when looking up the scale factor so the stiffness was not predictable. It was possible that segments passed from one processor to another for contact checking would have a zero stiffness and would therefore penetrate. The master side was likely to trigger an erroneous error about missing nodes, which terminated the job.
Compressive contact forces were erroneously "damaged" as well. Fix a bug affecting time-dependent slipring friction in 2d seatbelts. Fix erroneous 1d seatbelt slipring message that has been there since R8. Triangular elements were being deleted immediately by the distorted element check. This does not affect results, but allows models to run.
Add alternative mass calculation for critical time step estimate of cohesive elements. This hopefully resolves rarely occuring instability issues.
Inconsistent results were possible since version R9. Fix in the trimming of sandwich parts - irregular trimmed edge. Fixed a bug in running interpolation on load curve when there is only one frequency in the load curve.
Frequency domain response spectrum : Added missing arguments. Fixed a bug in extracting modal stress for response spectrum analysis. Added von mises stress output for beams.Subject Index. Engineering Page. We analyzed very complex structures. Physics developed the concepts and engineering made them deliverable. It was a great job and it was rewarding to help win the Cold War. Before becoming group leader, the last weapon system I worked on was the B See a web page on the B and here This is a page on Deployment.
The critical thinking required for engineering analysis is hard work and is like weight lifting for the brain.
Contact Friction I
The aluminum plate is 5" in diameter and is free to translate, simulating its being supported by a string. The first view is at the time of contact. The second view is after about half of the bullet's energy has been dissipated.
The 4th view is a close up showing the bullet's mesh detail and the fringes of stress. The calculation halts at this point because the mesh has distorted too much to continue without rezoning. I can be contacted via Email. The stress levels in a 6-PPC caliber Stolle Panda benchrest rifle action are shown at a peak internal chamber pressure of 50, psi. This pressure occurs during firing when the bullet has only traveled a short distance down the barrel.
Click Here to view the updated results. The first Figure shows the action with the bolt in the locked position. The second Figure shows only the bolt where the maximum stress level, in the lugs, is 87, psi. The third Figure is the action with a maximum stress level of only 41, psi. Note that the high stressed region of the bolt is in compression and occurs at the area of contact with the action. The stress levels are in psi, see the legend. To run this calculation out to seven time steps, took about 2 hours of number crunching.