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Publication Number: FHWA-HRT-04-096
Date: August 2005
Evaluation of LS-DYNA Wood Material Model 143
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This report documents the evaluation of a wood material model that has been implemented into the dynamic finite element code LS-DYNA, beginning with version 970. This material model was developed specifically to predict the dynamic performance of wood components used in roadside safety structures when undergoing a collision by a motor vehicle. This model is applicable for all varieties of wood when appropriate material coefficients are inserted. Default material coefficients for two wood varieties, southern yellow pine and Douglas fir, are stored in the model and can be accessed for use.
This report is one of two that completely documents this material model. The first report, Manual for LS-DYNA Wood Material Model 143 (FHWA-HRT-04-097), completely documents this material model for the user. The second report, Evaluation of LS-DYNA Wood Material Model 143 (FHWA-HRT-04-096), completely documents the model’s performance and the accuracy of the results. This performance evaluation was a collaboration between the model developer and the model evaluator. Regarding the model’s performance evaluation, the developer and the evaluator were unable to come to a final agreement regarding the model’s performance and accuracy. These disagreements are itemized and thoroughly discussed in chapter 17 of the second report.
This report will be of interest to research engineers associated with the evaluation and crashworthy performance of roadside safety structures, particularly those engineers responsible for the prediction of the crash response of such structures when using the finite element code LS-DYNA.
This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.
The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names appear in this report only because they are considered essential to the objective of the document.
Quality Assurance Statement
The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
The goal of the work performed under this program, Development of DYNA3D Analysis Tools for Roadside Safety Applications, is to develop wood and soil material models, implement the models into the LS-DYNA finite element code,(1) and evaluate the performance of each model through correlations with available test data.
Two reports are available for each material model. One report is a user’s manual; the second report is a performance evaluation. The user’s manual, Manual for LS-DYNA Wood Material Model 143,(2) thoroughly documents the wood model theory, reviews the model input, and provides example problems for use as a learning tool. It is written by the developer of the model. This report, Evaluation of LS DYNA Wood Material Model 143, comprises the performance evaluation for the wood model. It documents LS-DYNA parametric studies and correlations with test data performed by the model developer, and by a potential end user. The reader is urged to review the user’s manual before reading this evaluation report. A user’s manual(3) and evaluation report(4) are also available for the soil model.
The development of the wood model was conducted by the prime contractor. The associated wood model evaluation effort to determine the model‘s performance and the accuracy of the results was a collaboration between the developer and the potential end user, with the user’s evaluation intended to be independent of the developer’s evaluation. The developer partially evaluated the wood model. The potential end user performed a second independent evaluation of the wood model, provided finite element meshes for the evaluation calculations, and provided static post and bogie impact test data for correlations with the model.
Regarding the second independent evaluation of the wood model, the developer and evaluator were unable to come to a final agreement regarding several issues associated with the model‘s performance and accuracy. These issues are itemized and thoroughly discussed by the developer in chapter 17 of this evaluation report.
Throughout this report, the developer of the wood material model is referred to as the developer. The potential end user of the wood material model is referred to as the user. The developer’s calculations and conclusions are given in chapters 1 through 8 of this report. The user’s calculations and conclusions are given in chapters 9 through 16 of this report.
Table of Contents
List of Figures
List of Tables
Topics: research, safety, infrastructure, materials, construction safety
Keywords: research, safety, infrastructure, materials, wood, southern yellow pine, Douglas fir, LS DYNA, modeling and simulation, damage, rate effects, plasticity
TRT Terms: Roads--Guard fences--Mathematical models--Evaluation, Wooden fences--Mathematical models--Evaluation, Wood structures, Posts, Dynamic models, Finite element method, Simulation