Deformation and Energy Absorption of Steel Square Tubes With Optimized Shape Design

2019 ◽  
Author(s):  
Xiaofang Liu ◽  
Ziwen Fang ◽  
Haifeng Hong ◽  
Jianran Wang ◽  
Yanwen Liu ◽  
...  
Keyword(s):  
Impact Force ◽  
Longitudinal Direction ◽  
Axial Direction ◽  
Shape Design ◽  
Test Results ◽  
Element Analysis ◽  
Railway Vehicles ◽  
Side Walls ◽  
Energy Absorbers ◽  
Energy Absorbing

Abstract Square crush tubes have been widely used as impact energy absorbers in automotive and railway vehicles. In this paper, a square tube with vertical plates and dents has been designed to increase the controllability and stability of crash performance. Vertical plates are welded perpendicularly to the side walls of the tube, which increase the transverse stiffness and ensure the tube crashes in longitudinal direction under impact not in ideal axial direction. Dents have been put on the side walls near the front end of the tube to ensure the collapse always start from the front and progress gradually to the end. To validate the design, finite element analysis (FEA) and various experiments has been conducted and evaluated. Firstly, the numerical simulations were carried out using the software LS-DYNA. Then, four specimens were manufactured and tested. The crash velocity, tube deformation and impact force showed great agreement between the simulations and test results. The number of tubes, tube wall thickness, cross-section, trigger plates and dents arrangement can be adjusted to meet the requirements of different applications. In one application, the energy absorbing device with four crush tubes provided progressive controlled collapse with energy absorbing capacity of 1.22MJ and impact force less than 4450kN. This robust crush tube design has been successfully applied in multiple railway vehicles and also has the potential to be applied in other industries such as automotive vehicles.

Design and Optimization of Front-End Structure With Integrated Energy Absorption for Railway Vehicles

2020 ◽  
Author(s):  
Xiaofang Liu ◽  
Jianran Wang ◽  
Yanwen Liu ◽  
Ziwen Fang ◽  
Yanping Zhang ◽  
...  
Keyword(s):  
Impact Force ◽  
Critical Role ◽  
Iteration Process ◽  
Railway Vehicle ◽  
Test Results ◽  
Element Analysis ◽  
Design And Optimization ◽  
Front End ◽  
The Finite Element Analysis ◽  
Energy Absorbing

Abstract As the main energy absorbing area of a railway vehicle, the front-end structure is critical to reduce the collapse of the passenger area and increase the safety of the vehicle in case of collision. In this paper, a front-end structure with integrated energy absorbing is introduced in detail as well as the iteration process. The front-end structure is mainly composed of anti-climber, collision posts, corner posts and four kinds of crush elements including center crush elements, side crush elements, interior crush elements and head girders. The shape, dimension, position, connection and material of those components are optimized multiple times based on the finite element analysis results of various load cases. The finalized structure can provide progressive controlled collapse with energy absorbing capacity of 1.22MJ and impact force less than 4450kN. At the same time, it is capable to withstand a static longitudinal load of 1224kN and vertical load of 334kN. To validate the design and analysis, the front-end structure is manufactured and tested under impact. The crash velocity, deformation and impact force show great agreement between the simulations and test results. From the design and optimization of this front end structure, it is concluded that placing the crush elements behind the collision post is beneficial for static strength design, the energy absorbing capability can be largely increased without taking additional space by using interior crush element and the geometry of the head girders plays an critical role in balancing the force distribution and providing stable crush performance.

Design, Analysis and Test of Multi-Stage Crashworthiness Energy Absorbing Device for Railway Vehicles

2019 ◽  
Author(s):  
Haifeng Hong ◽  
Hongtao Liu ◽  
Ziwen Fang ◽  
Kefei Wang ◽  
Jianran Wang ◽  
...  
Keyword(s):  
Railway Vehicle ◽  
Test Results ◽  
Railway Vehicles ◽  
Multi Stage ◽  
Element Simulation ◽  
Sufficient Energy ◽  
Stage 4 ◽  
Third Stage ◽  
Energy Absorbing ◽  
Stage 1

Abstract An anti-collision and energy absorbing device is generally placed at the front end of railway vehicles to provide controlled collapse and sufficient energy absorbing capacity. In the conventional way, the energy absorbing device is usually designed as an integrated part of the carbody that can’t be easily replaced nor maintained after crash. To increase the maintainability and energy absorbing capacity of the energy absorbing device, a Multi-stage Crashworthiness Energy Absorbing Device has been developed, in which the first-stage and the second-stage energy absorbing units can be replaced or repaired under the collision that is not severe enough to initiate the third-stage energy absorbing unit. The Crashworthiness Energy Management (CEM) has four stages: coupler energy absorbing components (stage 1), honeycomb in the sliding center anti-climber (stage 2), metal peeling tubes mounted at the back of the fixed anti-climber (stage 3) and the structural components in the cab area (stage 4). By comparing the simulation results and test results, it is concluded that the finite element simulation model can provide dependable and accurate prediction for collision behaviors. Based on the design, simulation and test data, a safe, reliable and maintainable Multi-stage Crashworthiness Energy Absorbing Device has been verified and validated, which can provide valuable reference for researchers and engineers in the crashworthiness and railway vehicle industry.

Crash Tests of Tension Bolts in Light Safety Collision Devices

2008 ◽  
Vol 385-387 ◽  
pp. 685-688 ◽  
Author(s):  
Jin Sung Kim ◽  
Hoon Huh ◽  
Won Mog Choi ◽  
Tae Soo Kwon
Keyword(s):  
High Speed ◽  
Failure Load ◽  
Compressive Loading ◽  
Crash Test ◽  
Test Results ◽  
Element Analysis ◽  
Load Response ◽  
Collision Safety ◽  
Energy Absorbing ◽  
Crash Tests

This paper demonstrates the jig set for the crash test and the crash test results of the tension bolts with respect to an applied pre-tension. The tension and shear bolts are adopted at Light Collision Safety Devices as a mechanical fuse when tension bolts reach designed failure load. The kinetic energy due to the crash is absorbed by secondary energy absorbing devices after the fracture of tension bolts. One tension bolt was designed to be failed at the load of 375 kN. The jig set was designed to convert a compressive loading to a tensile loading and installed at the high speed crash tester. The strain gauges were attached at the parallel section of the tension bolts to measure the level of the pre-tension acting on the tension bolts. Crash tests were performed with a barrier whose mass was 250 kg and initial speed of the barrier was 9.5 m/sec. The result includes the load response of the tension bolts during both the crash tests and finite element analysis.

Modal Analysis on a High Speed Train Based on Forced Excitation From Track

2012 ◽  
Author(s):  
Lara Ma Erviti Calvo ◽  
Gorka Agirre Castellanos ◽  
Igor Alonso Portillo ◽  
Mayi Garcia Prada
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Impact Force ◽  
Impact Excitation ◽  
Modal Parameters ◽  
Maximum Speed ◽  
Vibration Modes ◽  
Test Results ◽  
High Speed Train ◽  
Railway Vehicles

The more demanding safety and comfort requirements combined with the increasing maximum speed of trains have lead to a growing concern in aspects such as the determination of the modal parameters of railway vehicles. Until now, the modal parameters of a vehicle have been obtained by EMA (Experimental Modal Analysis) based on the application of an impact force on the vehicle frame. However this kind of test is not optimal for railway vehicles because, due to their large dimensions, an impact force is unable to excite all the points of the structure. Also, with this method only the structural modes can be analyzed. Because of these drawbacks, a new modal analysis methodology is proposed, in which the excitation force comes from a specially designed shaker mounted under a point of a test track. In this manner, real excitation conditions can be simulated and it allows to determine not only the structural modes, but also the vibration modes associated with the suspensions. In first place, a description of the test facilities is presented. Afterwards, we present a test carried out in one of the coaches of a high speed train. The instrumentation employed, test methodology and test results are described. Finally, the test results are compared with the results obtained from a modal test in which impact excitation was used. Also the vibration modes obtained in the test are compared with the theoretical ones, which have been calculated with a combination of a FEM (Finite Element Method) and a MBS (Multi-Body Simulation).

Design and Analysis of Elastic-Plastic Collision Post for Railway Vehicles

2020 ◽  
Author(s):  
Hongtao Liu ◽  
Jianran Wang ◽  
Xiaofang Liu ◽  
Kefei Wang ◽  
Qi Luo ◽  
...  
Keyword(s):  
Element Analysis ◽  
Railway Vehicles ◽  
Front End ◽  
Operator Console ◽  
The Us ◽  
Overall Evaluation ◽  
Pros And Cons ◽  
Energy Absorbing ◽  
Two Stages ◽  
Absorbing Elements

Abstract Collision posts have been required at the front end of railway vehicles to provide protection against intrusion under collision in the US market since 1940s, though it is still not a standard required structure in the Europe and Asia markets. In this paper, typical front-end frame with and without collision posts of railway vehicles are compared to illustrate the pros and cons of collision posts in railway vehicles. Then two different front-end frames with collision posts are introduced in detail to discuss how to take the advantages of collision posts and avoid the drawbacks in different applications. In the first design, the collision posts are placed in front of the energy absorbing elements. When collision happens, the collision posts will deform first before the energy absorbing elements act. As a result, the collision posts and many carbody and cab structures, such as the front-end frame, underframe, cab interior and operator console may under repair even the collision speed is low. However, more space can be utilized for the cab and passenger compartment since the collision posts can be located at the very front of the vehicle. In the second design, there are two stages of energy absorbing elements and the collision posts are placed in the middle. The first stage of energy absorbing elements can absorb low-speed collision energy without damaging other structures and can be replaced easily. To make up for the extra space taken by the first stage energy absorbing elements, the shape and dimension of the collision posts have to be optimized. For both designs, finite element analysis has been used to analyze and optimize the design. Then full-scale test specimens are manufactured and tested to further validate the design and analysis. Based on the design, analysis and test results, an overall evaluation of collision post’s role in passenger protection and vehicle design has been generated.

scholarly journals Computational Evaluation for Age-Dependent Material Nonlinear Behavior of Aortic Wall Tissue on Abdominal Aortic Aneurysms

2018 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Chung-Won Lee ◽  
Up Huh ◽  
Ji-Hun You ◽  
Chi-Seung Lee ◽  
Ki-Hoon Kim ◽  
...  
Keyword(s):  
Abdominal Aorta ◽  
Nonlinear Behavior ◽  
Axial Direction ◽  
Tensile Tests ◽  
Aortic Aneurysms ◽  
Failure Stress ◽  
Test Results ◽  
Element Analysis ◽  
Computational Evaluation ◽  
Abdominal Aortic

An abdominal aortic aneurysm is a localized expansion of the abdominal aorta with a diameter >3 cm or >50% larger than the normal diameter. In this study, the stretch and strength of the materials in the abdominal aorta in patients with aneurysms were examined based on the results of tensile tests, and databases of failure stress and stretch were established according to age. Generally, the tensile test results of the axial and circumferential directions have become a priority in the tests of aortic materials. However, this study focused on the results of the axial direction. In addition, finite element analysis, where the Holzapfel model and the test results were applied, was performed. As a result, the behavior characteristics of the abdominal aortic materials were precisely simulated. The formula and material constants used in the Holzapfel model were studied and proposed in order to simulate the failure stress and stretch according to age as well as simulation.

scholarly journals The Development of a Rail Passenger Coach Car Crush Zone

Joint Rail ◽  
2003 ◽  
Author(s):  
Ronald A. Mayville ◽  
Kent N. Johnson ◽  
Richard G. Stringfellow ◽  
David C. Tyrell
Keyword(s):  
Finite Element Analysis ◽  
Primary Energy ◽  
Test Results ◽  
Element Analysis ◽  
Occupant Protection ◽  
Overall Design ◽  
Rail Vehicle ◽  
Design Requirements ◽  
Energy Absorbers ◽  
Crush Zone

This paper presents information on the design of a rail vehicle crush zone for better occupant protection. The overall design requirements and characteristics are described and the configuration for the various structural subsystems is presented. The paper also includes information on full-scale component tests carried out to support the development of the design, particularly for the primary energy absorbers. Comparisons between test and finite element analysis are presented and there is a discussion of how the test results have affected the design.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

scholarly journals Investigation of Energy-Absorbing Properties of a Bio-Inspired Structure

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 881
Author(s):  
Adrian Dubicki ◽  
Izabela Zglobicka ◽  
Krzysztof J. Kurzydłowski
Keyword(s):  
Absorption Capacity ◽  
Compression Tests ◽  
Element Analysis ◽  
Lightweight Structures ◽  
New Energy ◽  
Absorbing Material ◽  
Lightweight Structure ◽  
3D Printed ◽  
Deformation Force ◽  
Energy Absorbing

Numerous engineering applications require lightweight structures with excellent absorption capacity. The problem of obtaining such structures may be solved by nature and especially biological structures with such properties. The paper concerns an attempt to develop a new energy-absorbing material using a biomimetic approach. The lightweight structure investigated here is mimicking geometry of diatom shells, which are known to be optimized by nature in terms of the resistance to mechanical loading. The structures mimicking frustule of diatoms, retaining the similarity with the natural shell, were 3D printed and subjected to compression tests. As required, the bio-inspired structure deformed continuously with the increase in deformation force. Finite element analysis (FEA) was carried out to gain insight into the mechanism of damage of the samples mimicking diatoms shells. The experimental results showed a good agreement with the numerical results. The results are discussed in the context of further investigations which need to be conducted as well as possible applications in the energy absorbing structures.

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

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