LS-DYNA Simulation Influence on Roadside Hardware

2004 ◽  
Vol 1890 (1) ◽  
pp. 34-41 ◽  
Author(s):  
John D. Reid
Keyword(s):  
Roadside Hardware

Component and Full Scale Tests for Suspension Model Validation

2009 ◽  
Author(s):  
Pradeep Mohan ◽  
Dhafer Marzougui ◽  
Cing-Dao Kan ◽  
Kenneth Opiela
Keyword(s):  
Full Scale ◽  
Transportation Safety ◽  
Fe Model ◽  
George Washington ◽  
Model Library ◽  
Safety Research ◽  
Oblique Impacts ◽  
Full Scale Tests ◽  
Suspension Model ◽  
Roadside Hardware

The National Crash Analysis Center (NCAC) at the George Washington University (GWU) has been developing and maintaining a public domain library of LS-DYNA finite element (FE) vehicle models for use in transportation safety research. The recent addition to the FE model library is the 2007 Chevrolet Silverado FE model. This FE model will be extensively used in roadside hardware safety research. The representation of the suspension components and its response in oblique impacts into roadside hardware are critical factors influencing the predictive capability of the FE model. To improve the FE model fidelity and applicability to the roadside hardware impact scenarios it is important to validate and verify the model to multitude of component and full scale tests. This paper provides detailed description of the various component and full scale tests that were performed, specifically, to validate the suspension model of the 2007 Chevrolet Silverado FE model.

Improved Truck Model for Roadside Safety Simulations: Part I—Structural Modeling

2002 ◽  
Vol 1797 (1) ◽  
pp. 53-62 ◽  
Author(s):  
John D. Reid ◽  
Dhafer Marzougui
Keyword(s):  
Element Model ◽  
Free Edge ◽  
Realistic Model ◽  
Worcester Polytechnic Institute ◽  
Roadside Safety ◽  
Pickup Truck ◽  
Mesh Density ◽  
University Of Nebraska Lincoln ◽  
Improved Model ◽  
Roadside Hardware

Computer simulation is now a mainstream tool for design and analysis of roadside hardware. For the past several years, researchers at the National Crash Analysis Center, Worcester Polytechnic Institute, and the University of Nebraska–Lincoln have been improving various features of a 2000-kg pickup truck model, the most widely used vehicle model for roadside safety simulation. Many modeling techniques have been learned, and an improved model has been developed that should aid analysts at other locations who are performing similar simulations. The various effects and difficulties of “reducing” a finite element model to decrease computational costs are examined, including the elimination of initial penetrations, free-edge tangling, snagging, and “shooting nodes.” The elective refinement of mesh density, the elimination of manipulated material densities to achieve desired masses, the improvement of connections between components, and the inclusion of all significant parts to improve accuracy are analyzed. The significance of not oversimplifying critical components is emphasized, as well as the importance of realistic model behavior. Evolutionary changes to vehicle models are required as more information is obtained about modeling and truck behavior in roadside safety applications. Different research groups will have different modeling approaches, but by sharing the details of those approaches and by sharing models, the collective capabilities in roadside safety simulation will improve, ultimately resulting in better roadside hardware. The models described are thought to be a tremendous improvement over previous-generation models of the reduced pickup truck.

In-Service, Performance-Based Roadside Design Policy: Preliminary Insights from Washington State’s Bridge Rail Study

2000 ◽  
Vol 1720 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Venkataraman N. Shankar ◽  
Richard B. Albin ◽  
John C. Milton ◽  
Marylou Nebergall
Keyword(s):  
Statistical Study ◽  
National Policy ◽  
State Level ◽  
Washington State ◽  
Superior Performance ◽  
Statistical Framework ◽  
Strategic Direction ◽  
Accident Severity ◽  
Unobserved Effects ◽  
Roadside Hardware

Empirical insights about the performance of in-service roadside hardware are presented. A statistical study of bridge rail impacts on vehicular accident severity is presented from data collected in Washington State. In particular, concrete balusters and metal rails underperformed in comparison with the average bridge rail type, whereas thrie-beam guardrails and safety shape barriers had superior performance. The study presents a statistical framework that is particularly suitable for capturing real-world, unobserved effects that impact reported accident severity distribution. Policy sensitivities show systemwide savings through upgrading the underperforming rails to provide substantial performance. The combination of insights from the relative performance of bridge rails and the associated policy sensitivities provides direction for national policy on roadside design. In particular, the insights offer some strategic direction on inexpensive upgrades to state-level decision making.

Evaluation of Portable Concrete Barriers Using Finite Element Simulation

2000 ◽  
Vol 1720 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Dhafer Marzougui ◽  
George Bahouth ◽  
Azim Eskandarian ◽  
Leonard Meczkowski ◽  
Harry Taylor
Keyword(s):  
Finite Element ◽  
Safety Performance ◽  
Crash Test ◽  
Fe Model ◽  
Finite Element Software ◽  
Modeling Methodology ◽  
Element Simulation ◽  
Pcb Design ◽  
Concrete Barriers ◽  
Roadside Hardware

The use of finite element (FE) simulations in modeling and evaluating roadside hardware has increased significantly in the past few years. Thanks to the remarkable improvements in computer technology and finite element software, the crash behavior of automobiles and roadside hardware objects can be predicted. Finite element simulations were used to evaluate the safety of portable concrete barriers (PCB). The first step was to develop a methodology for creating accurate FE representations of PCBs. This objective was achieved by developing an FE model of an F-shape PCB design and using full-scale crash test data to validate the model. Once the fidelity and accuracy of the modeling methodology had been proved, FE models of two modified PCB designs were created and their safety performance was evaluated. Based on the simulation results, a third design was developed and its performance was analyzed. The safety performance of the three designs was compared.

Finite-Element Modeling of Guardrail Timber Posts and the Post-Soil Interaction

1998 ◽  
Vol 1647 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Chuck A. Plaxico ◽  
Gregory S. Patzner ◽  
Malcolm H. Ray
Keyword(s):  
Finite Element ◽  
Soil Conditions ◽  
Element Analysis ◽  
Soil System ◽  
Roadside Safety ◽  
Physical Tests ◽  
Simulation Results ◽  
Timber Guardrail ◽  
Roadside Hardware ◽  
Hardware Designs

The performance of many guardrail terminal systems is dependent on the strength of timber guardrail posts and soil conditions. Accurately simulating the breakaway characteristits of guardrail posts mounted in soils is an important issue concerning researchers in the roadside safety community. Finite-element analysis is one method that can be used to evaluate roadside hardware designs, but good simulations are contingent on developing accurate models of the components. A description is provided of the development of a model of a breakaway timber post and soil system used in the breakaway cable terminal (BCT) and the modified eccentric loader terminal (MELT). The model is described and simulation results are compared with data from physical tests of BCT/MELT posts.

Characterizing Guardrail Steel for LS-DYNA3D Simulations

1996 ◽  
Vol 1528 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Amy E. Wright ◽  
Malcolm H. Ray
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Material Behavior ◽  
Finite Element Models ◽  
Type Ii ◽  
Material Models ◽  
Class A ◽  
Model Geometry ◽  
Simulation Results ◽  
Roadside Hardware

Finite-element models have three parts: geometry, connections, and material properties. As the visible parts of a model, geometry and connections are generally carefully considered. Material properties often are not chosen with the same degree of care although they are equally important to obtaining good results. Accurate simulations of vehicles striking roadside hardware require an understanding of both the material behavior and the mathematical material models in LS-DYNA3D. A method for comparing LS-DYNA3D simulations with typical ASTM materials tests is described. The behavior and modeling parameters of guardrail steel (AASHTO M-180 Class A Type II) are examined in this study. Experimental and simulation results of quasistatic coupon tests are compared for AASHTO M-180 Class A Type II guardrail steel, and parameters for guardrail steel are recommended.

scholarly journals Modeling Tire Blow-Out in Roadside Hardware Simulations Using LS-DYNA

2003 ◽  
Author(s):  
Fabio Orengo ◽  
Malcolm H. Ray ◽  
Chuck A. Plaxico
Keyword(s):  
Real World ◽  
Full Scale ◽  
Strongly Coupled ◽  
Rubber Tire ◽  
Improved Model ◽  
Roadside Hardware ◽  
Crash Tests

Often when vehicles interact with roadside hardware like guardrails, bridge rails and curbs, the interaction between the roadside hardware and the tire causes the tire to lose its air seal and “blow-out”. Once the seal between the rim and rubber tire is lost, the tire deflates. The behavior of the deflated tire is much different than the behavior of an inflated tire such that when this behavior is observed in real world crashes or in full-scale crash tests, the vehicle kinematics are strongly coupled to the behavior of the deflated tire. Accounting for this behavior in LS-DYNA models is crucial in many types of roadside hardware simulations since the forces generated by the deflated tire often introduce instability into the vehicle that can cause rollover or spinout. This paper will present a method for accounting for tire deflation during LS-DYNA simulations and will present examples of the use of this type of improved model.

Enhancement of Vehicle/Roadside Hardware Crash: Dynamic Response of Child Occupant Involved in Vehicle/Pole Impact

2011 ◽  
Author(s):  
Ahmed Elmarakbi ◽  
Vid Krznaric ◽  
Khaled Sennah ◽  
William Altenhof ◽  
Michael Chapman
Keyword(s):  
Finite Element ◽  
Deformable Objects ◽  
Child Injuries ◽  
Soil Systems ◽  
Vehicle Impact ◽  
Hybrid Iii ◽  
Protection Devices ◽  
Energy Absorbing ◽  
Roadside Hardware ◽  
Child Occupant

This paper focuses on minimizing child injuries experienced during frontal vehicle-to-pole collisions by improving on the safety and energy absorption of existing traffic pole structures. A finite element computer model, using LS-DYNA software, is used to simulate crash events in order to determine the influence of pole structural and material characteristics on the injury parameters of a hybrid III 3-year-old child dummy occupant. Different pole support systems and laminar traffic poles of different materials are investigated in this paper. It is concluded that the anchored base support and the embedded pole in soil systems provide desirable crashworthy results, thus reducing fatalities and injuries resulting from vehicle impact. It is also recommended to mandate traffic protection devices in all areas with poor energy absorbing characteristics that resemble non-deformable objects.

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