d3VIEW & LS-DYNA Blog

LS-DYNA and D3VIEW helps BYU Students build PACE F1 Car

Published by Suri Bala August 27th, 2010 in LS-DYNA Bytes, d3View Features and d3view. 0 Comments

Over six months ago, two students, Rob Moncur, pursuing his MS, and Satyan Chandra, pursuing his UnderGraduate Studies, in Brigham Young University (BYU) set out on a path to build a LS-DYNA crash-analysis model of the PACE F1 car in under 8 weeks. Under the guidance of their professor, Dr. Greg Jensen, and with minimum support from myself, Rob and Satyan achieved, what seemed initially a very challenging task, to build a working crash-analysis model of the PACE F1 car as part of their course work. You can find their final report PACE_LSDYNA_FINALREPORT_Aug28.

LS-DYNA was used to simulate the crash-analysis event of the F1 car and all model development (assembly of meshed components) and post-processing was performed using LS-PrePost. As the collaboration between BYU and LSTC was done remotely from separate locations, d3VIEW aided in managing all data related to the PACE F1 crash-analysis model development using a simple web browser. Attached are some snapshots from the d3VIEW collaboration software.

Preliminary LS-DYNA Simulation (click to animate)

[D3VIEW] PACE Project Simulation Home (clink to enlarge)

[D3VIEW] PACE Project Recent Activities (clink to enlarge)

[D3VIEW] PACE Project Document Management (clink to enlarge)

[D3VIEW] Short Video

d3VIEW helps PACE group to build a F1 Car from d3view on Vimeo.

Dr. Greg Jensen was kind to share some prototype pictures. The PACE F1 prototype is currently in display at GM Tech Center in Warren, Michigan. Notice the LSTC logo located on the nose of the car

PACE F1 Car Prototype click to enlarge.

ABOUT

Brigham Young University is a reputed university based in UTAH.

LS-DYNA is a multi-physics and multi-stage linear-nonlinear finite element software that is the leading crash-analysis software in the world. LS-DYNA is developed by Livermore Software Technology (LSTC) headquartered in Livermore, Californina.

d3VIEW is a virtual product development collaboration web software that helps in managing all data from LS-DYNA.

Experimental Data Management inside d3VIEW

Published by Suri Bala August 19th, 2010 in d3View Features and d3view. 0 Comments

As a simulation engineer, we always like quick access to experimental data. Over the years, with a powerful framework that was developed within d3VIEW, this is now possible to import and visualize experimental data. With a few configurations, you can further tie this with simulation data for easy overlay and comparison. This following video shows how it can be done.

Experimental data management in d3VIEW from d3view on Vimeo.

Thick shells in contact

Published by Suri Bala August 13th, 2010 in LS-DYNA Contact. 0 Comments

During one of my recent trips, a question was raised about how LS-DYNA treats thick shells in contact in particular if the contact would detect the surface sides. This simulation Thickshells in contact shows that LS-DYNA treats the thickshells as solids in which all external (free) surfaces are included in the contact. ERODING contact would also regenerate the free surfaces upon element deletion.

Visualizing Dynamic Relaxation Convergence

Published by Suri Bala July 29th, 2010 in LS-DYNA Bytes and d3View Features. 0 Comments

Understanding the rate of convergence when employing Explicit Dynamic Relaxation can be very useful to track model sensitivity and to solve convergence problems. d3VIEW now has support to auto-extract the convergence information after a simulation is completed. It also processes DR graphics data to identify points of divergence.

Attached is a snapshot from a recent simulation that was used to study the number of cycles used to check for convergence in the event of a gravity initialization of a rigid sphere on a foam block. This study showed that if we have a higher number of cycles to check for convergence, then it is possible that we completely miss the convergence point and the problem could continue to oscillate about a median point. In a test problem of Gravity Initialization using Explicit DR, depending on using 100 or 1000 cycles between convergence checking, the sphere in the case of 1000 cycles actually converged on its rebound of the surface of the foam.

Click to Enlarge

SPC Constraints in Dynamic Relaxation to Improve Convergence

Published by Suri Bala July 26th, 2010 in LS-DYNA Bytes. 0 Comments

Dynamic Relaxation (DR) is a simple but effective technique to initialize structures to pre-loads prior to any primary load application. LS-DYNA has supported DR for several decades and is used by several users. Recently, in an attempt to improve convergence (Explicit DR or Implicit DR), there was a need to HOLD certain portion of a structure to reduce undesired movement. The problem with enforcing such constraints using BOUNDARY_SPC was they continue to be present in TRANSIENT phase as well which may not be desired.

One method to overcome this was to use BOUNDARY_PRESCRIBED_MOTION keyword (one for each DOF) and specify a zero displacement as a function of DR time and set SIDR=1 in the define curve. However, recent update to R5 enables uses to use BOUNDARY_SPC with BIRTH_DEATH option with DEATH eq 0.0 which causes the spc constraints to be honored in DR phase but they die as soon as LS-DYNA enters TRANSIENT phase.

Please refer the latest LS-DYNA manual under BOUNDARY_SPC for more information.

Visualizing User Generated Results into LS-OPT

Published by Suri Bala June 10th, 2010 in LS-OPT. 0 Comments

To view results from manual what-if studies, LS-OPT provides a great way to import these results so we can take advantage of its data visualization package. The attached image, an excerpt from the LS-OPT Manual, shows how we can do this.