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.

Improved Truck Model for Roadside Safety Simulations: Part II—Suspension Modeling

2002 ◽  
Vol 1797 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Paolo Tiso ◽  
Chuck Plaxico ◽  
Malcolm Ray
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Vehicle Suspension ◽  
Crash Test ◽  
Test Vehicle ◽  
Roadside Safety ◽  
Pickup Truck ◽  
Safety Research ◽  
Roadside Hardware

The 2000-kg pickup truck is a very important vehicle in roadside safety research because it is specified in many of the tests in NCHRP Report 350. The characteristics of the pickup truck make it a very demanding crash test vehicle. Because the 2000-kg pickup truck is an important crash test vehicle, it was the very first vehicle chosen for development of a finite element model. The nonlinear finite element program LS-DYNA has become an important feature of roadside hardware design and analysis in recent years, and much of the success of these modeling efforts is partly caused by the availability of a good 2000-kg pickup truck model. Like all models, the model has evolved over the past decade. New features and improvements have been added continuously to the model by many different teams to solve specific analysis problems. One particular area where there has been a great deal of activity is in the area of modeling the suspension properties of the vehicle. Suspension response is particularly important for 2000-kg pickup truck impacts because the vehicle often experiences stability problems in impacts with roadside hardware. A number of improvements and modifications to Version 9 of the NCAC 2000-kg pickup truck model are summarized. These improvements involved changing the finite element model, changing element properties, and obtaining suspension response properties from physical tests. The 2000-kg truck model was then validated against a series of low-speed, live-drive tests with an instrumented pickup truck. The improved model provides more realistic vehicle suspension response than earlier models and should prove to be a valuable addition to future finite element modeling activities.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

New Energy-Absorbing High-Speed Safety Barrier

2003 ◽  
Vol 1851 (1) ◽  
pp. 53-64 ◽  
Author(s):  
John D. Reid ◽  
Ronald K. Faller ◽  
Jim C. Holloway ◽  
John R. Rohde ◽  
Dean L. Sicking
Keyword(s):  
High Speed ◽  
Steel Tube ◽  
Full Scale ◽  
Element Analysis ◽  
Dynamic Component ◽  
Testing Program ◽  
Roadside Safety ◽  
New Energy ◽  
University Of Nebraska Lincoln ◽  
Energy Absorbing

For many years, containment for errant racing vehicles traveling on oval speedways has been provided through rigid, concrete containment walls placed around the exterior of the track. However, accident experience has shown that serious injuries and fatalities may occur through vehicular impacts into these nondeformable barriers. Because of these injuries, the Indy Racing League and the Indianapolis Motor Speedway, later joined by the National Association for Stock Car Auto Racing (NASCAR), sponsored the development of a new barrier system by the Midwest Roadside Safety Facility at the University of Nebraska–Lincoln to improve the safety of drivers participating in automobile racing events. Several barrier prototypes were investigated and evaluated using both static and dynamic component testing, computer simulation modeling with LS-DYNA (a nonlinear finite element analysis code), and 20 full-scale vehicle crash tests. The full-scale crash testing program included bogie vehicles, small cars, and a full-size sedan, as well as Indy Racing League open-wheeled cars and NASCAR Winston Cup cars. A combination steel tube skin and foam energy-absorbing barrier system, referred to as the SAFER (steel and foam energy reduction) barrier, was successfully developed. Subsequently, the SAFER barrier was installed at the Indianapolis Motor Speedway in advance of the running of the 2002 Indianapolis 500 race. From the results of the laboratory testing program as well as analysis of the accidents into the SAFER barrier occurring during practice, qualification, and the race, the SAFER barrier has been shown to provide improved safety for drivers impacting the outer walls.

scholarly journals A dynamic model of cylindrical plunge grinding process for chatter phenomena investigation

2018 ◽  
Vol 148 ◽  
pp. 09004
Author(s):  
Paweł Lajmert ◽  
Małgorzata Sikora ◽  
Dariusz Ostrowski
Keyword(s):  
Degrees Of Freedom ◽  
Stability Limit ◽  
Element Model ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Plunge Grinding ◽  
Chatter Vibrations ◽  
Grinding Conditions ◽  
The Stability ◽  
Improved Model

In the paper, chatter vibrations in the cylindrical plunge grinding process are investigated. An improved model of the grinding process was developed which is able to simulate self-excited vibrations due to a regenerative effect on the workpiece and the grinding wheel surface. The model includes a finite-element model of the workpiece, two degrees of freedom model of the grinding wheel headstock and a model of wheel-workpiece geometrical interferences. The model allows to studying the influence of different factors, i.e. workpiece and machine parameters as well as grinding conditions on the stability limit and a chatter vibration growth rate. At the end, simulation results are shown and compared with exemplified real grinding results.

A reaction-force-validated soccer ball finite element model

2016 ◽  
Vol 231 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Reaction Force ◽  
Element Model ◽  
Optimal Number ◽  
Ball Impact ◽  
Soccer Ball ◽  
Mesh Density ◽  
Good Agreement

The soccer ball is one of the important pieces of equipment in the game of soccer. It undergoes various forms of impact during the game. In order to numerically investigate the occasions of ball impact such as soccer heading, a validated finite element model of a soccer ball is required. Therefore, a model was developed incorporating material properties obtained from literature. To ensure the accuracy of the model, it was validated against an established soccer ball model and experimental data of the coefficient of restitution, contact time, longitudinal deformation and reaction force. In addition, a parametric study of the mesh density was also performed to determine the optimal number of elements. The developed soccer ball model was found to be in a good agreement with the literature and experimental data. This suggests that, the soccer ball model is capable of replicating the impacts of interest. This article details the development of the model and the validation processes.

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.

Design and Validation of a 30,000 kg Heavy Goods Vehicle Using LS-DYNA

2005 ◽  
Author(s):  
Ali O. Atahan ◽  
Guido Bonin ◽  
Mustafa El-Gindy
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Crash Test ◽  
Roadside Safety ◽  
Software Technology ◽  
Crash Testing ◽  
Steering Mechanism ◽  
Technology Corporation ◽  
Crash Tests

Extraordinary developments in virtual crash testing research have been achieved during the past decade. Advancements in hardware and software technology along with improvements in computation mechanics and increased number of full-scale crash tests contributed positively to the development of more realistic finite element models. Use of complex finite element codes based on computational mechanics principles allowed the virtual reproduction of real world problems. Regarding roadside safety, the design phase was, until now, based on the use of simplified analysis, unable to describe accurately the complexity of vehicle impacts against safety hardware. Modeling details, such as geometry, constitutive laws of the materials, rigid, kinematic and other links between bodies, definition and characterization of contact surfaces are necessary to build an accurate finite element model for an impact problem. This set of information is needed for each different body involved in the event; making the development of a complete model very much demanding. Once a part (subset) of the entire model has been accurately validated against real experimental data, it can be used again and again in other analogous models. In this paper, finite element model of a unique Heavy Goods Vehicle (HGV) was developed and partially validated using actual crash test data. Development of this particular vehicle model was important since this vehicle is extensively used in Europe to test the structural adequacy of high containment level (H4a) safety barriers according to EN 1317 standard. The HGV model studied reproduces a FIAT-IVECO F180 truck, a vehicle with 4 axles and a mass of 30,000 kg when fully loaded. The model consisted of 12,337 elements and 11,470 nodes and was built for and is ready to use with LS-DYNA finite element code from Livermore Software Technology Corporation. Results of the validation study suggest that the developed HGV model shows promise and can be used in further studies with confidence. Improvements such as, steering mechanism in front axes and suspension system is currently underway to make model more realistic.

Development of Metal-Cutting Guardrail Terminal

1996 ◽  
Vol 1528 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Brian G. Pfeifer ◽  
Dean L. Sicking
Keyword(s):  
Metal Cutting ◽  
Performance Standards ◽  
Full Scale ◽  
Dynamic Component ◽  
Roadside Safety ◽  
University Of Nebraska Lincoln ◽  
The University ◽  
The Impact ◽  
Crash Tests ◽  
Impact Head

A crashworthy terminal for strong-post W-beam guardrail systems was developed at the Midwest Roadside Safety Facility at the University of Nebraska—Lincoln. The terminal incorporates an impact head that is placed over the end of a tangent section of W-beam rail. The impact head is designed to be pushed down the rail and to dissipate impact energy by cutting the W-beam along the peaks and valley to produce four essentially flat strips of steel. These flat strips are then deflected out of the path of the vehicle, striking the end of the rail. Static and dynamic component tests as well as full-scale developmental crash tests conducted during the development of this system are described. Finally, the results of the three full-scale compliance crash tests are presented and discussed. The metal-cutting guardrail terminal was shown to meet NCHRP Report 230 safety performance standards.

Nonlinear Analysis of Jointed Concrete Pavements

1998 ◽  
Vol 1629 (1) ◽  
pp. 50-57 ◽  
Author(s):  
M. Asghar Bhatti ◽  
Idelin Molinas-Vega ◽  
James W. Stoner
Keyword(s):  
Nonlinear Analysis ◽  
Element Model ◽  
Concrete Slabs ◽  
Relative Deformation ◽  
Concrete Pavements ◽  
Fatigue Damage Accumulation ◽  
Repetitive Loading ◽  
Using Data ◽  
Improved Model ◽  
Jointed Concrete Pavements

A finite element model for nonlinear analysis of jointed concrete pavements is presented. The model allows for nonlinear representation of the properties of concrete, both in compression and in tension. It also accounts for the behavior under cyclic loading considering the nonlinear fatigue damage accumulation in concrete. An improved model accounting for the relative deformation between the dowel bars and the concrete slabs is presented to analyze pavement slabs connected with dowels. The sub-grade model is capable of representing pumping of the fine material with repetitive loading. Limited validation of the model is presented using data available in the literature.

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