scholarly journals CRASHWORTHINESS ANALYSIS OF THE STRUCTURE OF METRO VEHICLES CONSTRUCTED FROM TYPICAL MATERIALS AND THE LUMPED PARAMETER MODEL OF FRONTAL IMPACT

Transport ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 75-88 ◽  
Author(s):  
Tao Zhu ◽  
Shou-Ne Xiao ◽  
Guang-Zhong Hu ◽  
Guang-Wu Yang ◽  
Chao Yang
Keyword(s):  
Energy Absorption ◽  
Dynamic Stiffness ◽  
Vehicle Body ◽  
Fe Model ◽  
Frontal Impact ◽  
Rigid Barrier ◽  
Car Body ◽  
Absorption Ratio ◽  
Collision Force ◽  
Energy Absorption Ratio

This paper establishes a Finite Element (FE) model of a rigid barrier impact of a single vehicle constructed from carbon steel, stainless steel, and aluminum alloy, which are three typical materials used in metro vehicle car body structures. The different responses of the three materials during the collision are compared. According to the energy absorption, velocity, deformation and collision force flow characteristics of each vehicle, the relationship between the energy absorption ratio of the vehicle body and the energy absorption ratio of its key components is proposed. Based on the collision force flow distribution proportion of each component, the causes of the key components’ deformation are analysed in detail. The internal relationship between the deformation, energy absorption and impact force of the key components involved in a car body collision is elucidated. By determining the characteristic parameters describing the vehicle’s dynamic stiffness, a metro vehicle frontal impact model using lumped parameters is established that provides a simple and efficient conceptual design method for railway train safety design. These research results can be used to guide the design of railway trains for structural crashworthiness.

Multi-Objective Crashworthiness Optimization of Composite Hat-Shape Energy Absorber Using GMDH-Type Neural Networks and Genetic Algorithms

2010 ◽  
Author(s):  
Naser Tavassoli ◽  
Bahram Notghi ◽  
Abolfazl Darvizeh ◽  
Mansour Darvizeh
Keyword(s):  
Neural Networks ◽  
Energy Absorption ◽  
Failure Criterion ◽  
Design Procedure ◽  
Vehicle Body ◽  
Group Method ◽  
Nsga Ii ◽  
Car Body ◽  
Multi Objective ◽  
Conflicting Objectives

Reducing the weight of car body and increasing the crashworthiness capability of car body are two important objectives of car design. In this paper, a multi-objective optimization for optimal composite hat-shape energy absorption system is presented At the first, the behaviors of the hat shape under impact, as simplified model of side member of a vehicle body, are studied by the finite element method using commercial software ABAQUS. Two meta-models based on the evolved group method of data handling (GMDH) type neural networks are then achieved for modeling of both the absorbed energy (E) and the Tsai-Hill Failure Criterion (TS) with respect to geometrical design variables using those training and testing data obtained models. The obtained polynomial neural meta-models are finally used in a multi-objective optimum design procedure using NSGA-II with a new diversity preserving mechanism for Pareto based optimization of hat-shape. Two conflicting objectives such as maximizing the energy absorption capability (E), minimizing the Tsai-Hill Failure Criterion are considered in this work.

Effects of Fall Height and Impact Strategy on Energy Absorption Ratio Between Shoulder Joint and Elbow Joint

2017 ◽  
Vol 38 (3) ◽  
pp. 378-386
Author(s):  
Paul Pei-Hsi Chou ◽  
Shu-Zon Lou ◽  
Yen-Po Huang ◽  
Hon-Yu Chen ◽  
You-Li Chou
Keyword(s):  
Energy Absorption ◽  
Shoulder Joint ◽  
Elbow Joint ◽  
Absorption Ratio ◽  
Energy Absorption Ratio ◽  
Fall Height

Numerical Simulation of Automotive Crash-Box Subjected to Low Velocity Frontal Impact

2009 ◽  
Vol 417-418 ◽  
pp. 17-20 ◽  
Author(s):  
Qing Fen Li ◽  
Yan Jie Liu ◽  
Hai Dou Wang ◽  
Sheng Yuan Yan
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Large Strain ◽  
Circular Cross Section ◽  
Shell Element ◽  
Fe Model ◽  
Frontal Impact ◽  
Low Velocity ◽  
Fe Method ◽  
Thin Walled

Thin walled tubes, particularly those of square or circular cross-section, are the common types of automobile crash-box, which equipped at the front end of a car, is one of the most important automotive parts for crash energy absorption. In the present work, energy absorption characters of square and circular cross-section thin walled tubes at low-velocity frontal impact are investigated respectively by using finite element (FE) method. The numerical simulations were carried out using the software LS-DYNA. The tubes were modeled using shell element of designation Belytschko-Tsay, which is suitable for large strain analyses. The FE model of the tube was validated by comparing the theoretical calculation results, experimental results and FE model results. Results show that on average the difference of these results was within 10%. The good correlation of results obtained show that the numerical analyses are reliable.

Rails Deformation Pattern in Frontal Impact

2002 ◽  
Author(s):  
Joseph Hassan ◽  
Guy Nusholtz ◽  
Ke Ding
Keyword(s):  
Wave Propagation ◽  
Real World ◽  
Stress Waves ◽  
Stress Wave Propagation ◽  
Deformation Pattern ◽  
Frontal Impact ◽  
Rigid Barrier ◽  
Final Deformation ◽  
Deformation Patterns ◽  
The Impact

During a vehicle crash stress waves can be generated at the impact point and propagate through the vehicle structure. The generation of these waves is dependent, in general, on the crash type and, in particular, on the impact contact characteristics. This has consequences with respect to different crash barrier interfaces for vehicle evaluation. The two barriers most commonly used to evaluate the response of a vehicle in a frontal impact are the rigid barrier and the offset deformable barrier. They constitute different crash modes, full frontal and offset. Consequently it would be expected that there are different deformation patterns between the two. However, an additional possible contributor to the difference is that an impact into a rigid barrier generates waves of significantly greater stress than impacts with the deformable one. If stress waves are a significant component of real world final deformation patterns then, the choice of barrier interface and its effective stiffness is critical. To evaluate this conjecture, models of two types of rails each undergoing two different types of impacts, are analyzed using an explicit dynamic finite element code. Results show that the energy perturbation along the rail depends on the barrier type and that the early phase of wave propagation has very little effect on the final deformation pattern. This implies that in the real world conditions, the stress wave propagation along the rail has very little effect on the final deformed shape of the rail.

Optimization of the Global Static and Dynamic Performance of a Vehicle Body by Means of Response Surface Models

2012 ◽  
Author(s):  
Pavlina Mihaylova ◽  
Alessandro Pratellesi ◽  
Niccolò Baldanzini ◽  
Marco Pierini
Keyword(s):  
Response Surface ◽  
Dynamic Performance ◽  
The Body ◽  
Vehicle Body ◽  
Fe Model ◽  
Structural Modifications ◽  
Response Surface Models ◽  
First Choice ◽  
Surface Models ◽  
Body In White

Concept FE models of the vehicle structure are often used to optimize it in terms of static and dynamic stiffness, as they are parametric and computationally inexpensive. On the other hand they introduce modeling errors with respect to their detailed FE equivalents due to the simplifications made. Even worse, the link between the concept and the detailed FE model can be sometimes lost after optimization. The aim of this paper is to present and validate an alternative optimization approach that uses the detailed FE model of the vehicle body-in-white instead of its concept representation. Structural modifications of this model were applied in two different ways — by local joint modifications and by using mesh morphing techniques. The first choice was motivated by the strong influence of the structural joints on the global vehicle performance. For this type of modification the plate thicknesses of the most influent car body joints were changed. In the second case the overall car dimensions were modified. The drawback of using detailed FE models of the vehicle body is that they can be times bigger than their concept counterparts and can thus require considerably more time for structural analysis. To make the approach proposed in this work a feasible alternative for optimization in the concept phase response surface models were introduced. With them the global static and dynamic performance of the body-in-white was represented by means of approximating polynomials. Optimization on such mathematical models is fast, so the choice of the optimization algorithm is not limited only among local-search strategies. In the current study Genetic Algorithm was used to increase the chances for finding better design alternatives. Two different optimization problems were defined and solved. Their final solutions were presented and compared in terms of structural modifications and resulting responses. The approach in this paper can be successfully used in the concept phase as it is fast and reliable and at the same time it avoids the problems typical for concept models.

The Analysis and Improvement for Side Impact of Car Body Structure

2013 ◽  
Vol 456 ◽  
pp. 38-42
Author(s):  
Ai Hong Gong ◽  
Ming Mao Hu
Keyword(s):  
Side Impact ◽  
Fe Model ◽  
Body Structure ◽  
Impact Performance ◽  
Car Body ◽  
Euro Ncap ◽  
Virtual Test ◽  
Structure Improvement ◽  
Moving Deformable Barrier ◽  
The Impact

Based on the finite element (FE) model and Moving Deformable barrier (MDB) model of a car side impact, the virtual test of the side impact was conducted with HYPERWORK software according to Euro-NCAP regulation. Then the impact performance was evaluated in both deformation and response curve of the car body, and the problem of the crashworthiness in designing the side structure was analyzed. Finally, the structure improvement with CATIA for the side crashworthiness was proposed. Keywords: CAE analyze, Side impact, Improvement

A comprehensive method for studying the degree of thermal damage to steel elements of vehicles using field methods

2021 ◽  
Vol 93 ◽  
pp. 137-151
Author(s):  
Yu. D. Motorygin ◽  
◽  
G. A. Sikorova ◽  
Keyword(s):  
High Temperatures ◽  
Thermal Damage ◽  
Vehicle Body ◽  
Fuel Load ◽  
Complex Method ◽  
Main Task ◽  
Field Methods ◽  
Car Body ◽  
Comprehensive Method ◽  
Independent Field

Introduction. Every year, the number of registered motor vehicles in Russia increases, with an increase of 30 % over the past 10 years. The desire to extend the service life of existing vehicles leads to an increase in breakdowns that lead to fire. The task of identifying places where there was an emergency situation that led to a fire is difficult, especially in the case of a complete burnout of the fuel load of the car. Goals and objectives. The purpose of the work is to create a methodology by which it is possible to conduct studies of cold-formed steel products of the vehicle body to determine the zone of the greatest thermal damage. Each method determines one of the characteristics that changes when the steel is exposed to high temperatures. The main task of the work is to test the possibility of applying these methods in a certain sequence to determine the zone that has undergone more annealing. Research methods. The complex method includes induction thickness measurement, which allows measuring the thickness of a layer of high-temperature oxide; a method for measuring the coercive force or demagnetization currents, as well as a method for measuring microhardness. The latter method will determine the decrease in the hardness of the vehicle body after exposure to high temperatures. Results and its discussion. The obtained data on the degree of thermal damage to cold-deformed steel products of the car body by three independent field methods will increase the reliability of the combustion start zone, which in turn will determine the search zone for the cause of ignition. Conclusion. Determining the specific cause of the fire during the maintenance, repair and operation of vehicles will allow you to exclude similar emergency modes in the future. The introduction of a comprehensive method for investigating the condition of an object after a fire will significantly increase the level of reliability of the results obtained when searching for a breakdown that led to a fire. Keywords: fire source, car body, thermal changes, field methods, complex technique, magnetic properties, scale thickness, microhardness

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