MIDWEST STATES POOLED FUND PROGRAM
Annual LS-DYNA Modeling Enhancement Support
Sponsoring Agency Code
TPF-5(193) Supplement 51
Over the last decade, the LS-DYNA finite element analysis program has become one of the primary numerical modeling tools for use in the development and/or preliminary evaluation of roadside safety features. Although LS-DYNA has been used often and successfully by roadside safety researchers and engineers, there still remain several limitations for its use that are solely based on the inability to focus on basic modeling.
Previously, some limited funding existed for such efforts. These research funds were distributed by FHWA throughout the Centers of Excellence. However, this funding source has been eliminated. In order for MwRSF researchers to continue to advance the state-of-the-art for LS-DYNA modeling within the roadside safety community as well as to enhance MwRSF's analysis capabilities for future Pooled Fund projects, it is requested that the Pooled Fund Program member states provide a limited amount of funds to be allocated annually for the following types of efforts:
1. Investigation of advanced modeling techniques and LS-DYNA capabilities
a. Bolted connections, fracture and failure modes, cable modeling, etc
2. Investigation of advanced material modeling
a. Modeling of concrete, wood, soil
3. New and improved vehicle modeling
a. MASH vehicles, suspension, tires, windshield and laminated glass, failure modes
Over the past year, due to several other projects requiring LS-DYNA simulations using some version of the MGS, it was decided to use funds from this project to improve the MGS model currently being used at MwRSF. Chosen to be the first portion of the model to be updated was the end anchorage. Images of the old and newly developed end anchorage are shown in Figure 3 through Figure 5. The entire anchorage model was totally re-done, including more precise geometry and all parts now being included in the model.
Recently, LS-DYNA has been used on several MwRSF projects, including (1) high-tension cable barrier end terminal development, (2) MGS minimum effective guardrail length (this project uses the new end anchorage model), (3) TL-2 analysis and placement on slope of the no-blockout MGS on Gabion wall, and (4) SAFER for highway applications.
The objective of this research effort is to advance roadside safety simulation procedures using LS-DYNA which will ultimately allow for improved safety hardware design. Annual funding will be used to address specific modeling needs shared by many safety programs.
Funding from this project would go to annual support of advancement of LS-DYNA modeling capabilities at MwRSF. The exact nature of the issues to be studied would be determined by the most pressing simulation problems associated with current Pooled Fund projects.
At this time, further LS-DYNA work will concentrate on the new MGS anchorage model. The overall goal is to increase the accuracy of our MGS model by incorporating newer modeling techniques that were either not known or too CPU expensive when the model was first developed many years ago.
Bogie testing on the end anchorage system is scheduled for 2011 under a separate project. This testing will provide physical behavior of the system during impact, including loads through the components and connections. Additionally, the movement through the soil of the anchorage will be captured. Results from the bogie testing will be used to calibrate and validate the new model. Next the new anchorage model will be incorporated into the MGS model and various studies will be performed to ensure it is behaving as required.
If time permits, LS-DYNA work will continue on developing the 1100C surrogate model to be used for various MwRSF projects.
Annual support of LS-DYNA modeling enhancements will advance the current state-of-the-art for computer simulation and provide the following benefits for the entire industry:
1. Improved roadside safety hardware.
2. Reduced development time and cost.
3. Improved understanding of the behavior of roadside safety features, especially for impacts outside of normal crash test conditions.
4. Improved confidence in models.
Snapshot of Recent Developments
130 Whittier Research Center
2200 Vine Street
Lincoln, Nebraska 68583-0853
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