scholarly journals Crash Energy Management of Vehicle Front-end Structures Considering Multiple Conditions: Modelling and Solution Method

2021 ◽  
Author(s):  
Danqi Wang ◽  
Junyuan Zhang ◽  
Shihang Wang
Keyword(s):  
Energy Absorption ◽  
Energy Management ◽  
Analytical Model ◽  
Solution Method ◽  
Dynamic Responses ◽  
Frontal Crash ◽  
Evaluation Indexes ◽  
Decomposition Scheme ◽  
Front End ◽  
Vehicle Crash

Abstract For the vehicle frontal crash development, matching the stiffness of the front end structures reasonably, i.e., impact energy management, can effectively improve the safety of vehicle. A multi-condition analytical model for vehicle frontal crash is construct by three dimensional decomposition theory. In the analytical model, the spring is used to express the equivalent stiffness of the local energy absorption space at the front-end structure. Then based on the analytical model, the dynamic responses and evaluation indexes of the vehicle in MPDB and SOB conditions are derived with input of crash pulse decomposition scheme. Comparing the actual vehicle crash data and the finite element simulation results with the calculation results of the proposed solution method, the error is less than 15%, which verifies validity of the modeling and the accuracy of the solution. Finally, based on the solution method in the MPDB and the SOB conditions, the sensitivities of crash pulse decomposition scheme to evaluation indexes are analyzed to obtain qualitative rules which guide crash energy management. This research reveals the energy absorption principle of front-end structure during the frontal impact process, and provides an effective tool to manage the vehicle crash energy considering multi-condition.

The effects of geometric offsets on the dynamic responses of a Scott—Russell amplifying mechanism with flexible hinges

2009 ◽  
Vol 223 (10) ◽  
pp. 2413-2423 ◽  
Author(s):  
C-M Chen ◽  
R-F Fung
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Dynamic Responses ◽  
Analytical Models ◽  
Dynamic Equations ◽  
Magnification Factor ◽  
Flexure Hinges ◽  
Magnification Factors ◽  
Straight Line ◽  
Deviation Factor

The dynamic equations of a micro-positioning Scott—Russell (SR) mechanism associated with two flexible hinges and an offset are developed to calculate output responses. Both rigid and flexible hinges are considered to explore the results. The main features in the kinematics of the SR mechanism are its displacement amplification and straight-line motion, which are widely needed in practical industries. The manufacturing inaccuracy of the SR mechanism definitely causes geometric offsets of flexure hinges, and affects displacement amplification and straight-line output motion. Analytical models based on kinematics and Hamilton's principle are derived to explore the variation of linearity ratio, magnification factor, and deviation factor due to various offsets and link lengths. From numerical simulations for the SR mechanism with various offsets of flexible hinges in the conditions of different link lengths, it is found that offsets of flexure hinges obviously affect the amplifying factor and linearity ratio, and appear to dominate the changes of magnification factors. Moreover, an analytical model is also used to predict magnification factors due to various offsets. Finally, some conclusions concerning the effects of offset on the performance of the SR mechanism are drawn.

Estimation of energy-absorption space for pedestrian leg protection of car front-end structures

2012 ◽  
Vol 60 (1/2) ◽  
pp. 20 ◽  
Author(s):  
Jun Huang ◽  
Yong Xia ◽  
Bingbing Nie ◽  
Qing Zhou
Keyword(s):  
Energy Absorption ◽  
Front End

Characterization of Frontal Crash Pulses

2000 ◽  
Author(s):  
Hikmat F. Mahmood ◽  
Fadhel Aouadi
Keyword(s):  
Pulse Duration ◽  
Test Data ◽  
Frontal Crash ◽  
Design Information ◽  
Injury Criteria ◽  
Front End ◽  
Time Zones

Abstract This paper presents test data of more than 30 vehicles of different manufacturer, weight and front-end length. The relationships between the vehicle frontal NCAP pulse, the dummy response and the vehicle characteristics are shown in many figures. Vehicle frontal pulses were characterized and analyzed by considering different time zones within the pulse duration: bumper effect zone (0 ms. to 5 ms.), engine effect zone (18 ms. to 35 ms.), dummy engagement zone (48 ms. to 68 ms.). Also, ratios and delays between rocker pulse and the dummy chest and head pulses are computed and analyzed. The purpose of this study is not to develop a crash pulse but to generate design information that can assist in the design of front-end structure to meet injury criteria.

scholarly journals Dynamic responses and energy absorption of hollow sphere structure subjected to blast loading

2019 ◽  
Vol 181 ◽  
pp. 107920 ◽  
Author(s):  
Fan Tang ◽  
Yanlong Sun ◽  
Zerong Guo ◽  
Wensu Chen ◽  
Mengqi Yuan
Keyword(s):  
Energy Absorption ◽  
Hollow Sphere ◽  
Blast Loading ◽  
Dynamic Responses

INVESTIGATING THE EFFECT OF SLOSHING ON THE ENERGY ABSORPTION OF TANK WAGONS CRASH

2015 ◽  
Vol 39 (2) ◽  
pp. 187-200 ◽  
Author(s):  
Reza Razaghi ◽  
Majid Sharavi ◽  
Mohammad Mahdi Feizi
Keyword(s):  
Energy Absorption ◽  
Solution Method ◽  
Crash Test ◽  
Test Results ◽  
Software Simulation ◽  
Fluid Sloshing ◽  
Mass Spring Model ◽  
Solution Methods ◽  
Height Increase ◽  
Mass Spring

One of the main fluid mechanics phenomena is fluid sloshing which is originated from the free surface of fluid and should be taken into account in design of fluid structures such as fuel tank wagons, ships and so on. The aim of this paper is to investigate the effect of tank fluid sloshing on energy absorption and reducing tank acceleration during the tank wagon impact. For this purpose, methods of software simulation and dynamics solution methods are accomplished. The assumed wagon includes a tank with the approximate volume of 95 m3 and capacity of 65 tons of fluid. Using finite element method, the tank impact is simulated based on the corresponding standards for different heights of fluid in the tank. Obtained results show fluid height increase has an inappropriate effect on energy absorption among impact however the more fluid in tank, the more time would be consumed for energy absorption in general. At the end, by using crash test results for a tank with aforementioned scale, validity of impact software simulation and dynamic solution method considering the tank fluid as mass-spring model are checked.

EVALUATION OF ANALYTICAL AND FINITE ELEMENT MODELING ON PIEZOELECTRIC CANTILEVER BIMORPH ENERGY HARVESTER

2013 ◽  
Vol 37 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zhengchao Xie
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Analytical Model ◽  
Energy Harvester ◽  
Electrical Energy ◽  
Working Environment ◽  
Dynamic Responses ◽  
Power Sources ◽  
Element Modeling ◽  
Piezoelectric Cantilever

Harvesting the electrical energy from their working environment has become a feasible choice of realizing self-powered systems or providing supplementary power sources to the battery. In this paper, a pre-loaded piezoelectric cantilever bimorph (PCB) energy harvester is adopted as the research object, for which a single degree-of-freedom analytical model and finite element modeling have been carried out to study its dynamic responses. The laboratory experiments have also been performed to validate the analytical and the finite element modeling. It shows that finite element modeling has a better agreement with the experimental results than the analytical model, while the latter has a rough accuracy and can be used to obtain quick estimations of the dynamic response of the PCB energy harvester in certain cases.

scholarly journals Variable Stiffness Design and Multiobjective Crashworthiness Optimization for Collision Post of Subway Cab Cars

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 246
Author(s):  
Wei Guo ◽  
Ping Xu ◽  
Zhaofeng Yi ◽  
Jie Xing ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Response Surface ◽  
Energy Absorption ◽  
Pareto Frontier ◽  
Variable Stiffness ◽  
Element Model ◽  
Surface Model ◽  
Front End ◽  
The Finite Element Model

This paper proposes a variable stiffness collision post (VSCP) structure based on a uniform stiffness collision post (USCP) structure and performs stiffness matching optimization for VSCPs. A collision post structure assembled in a subway front-end frame can maintain the living space and absorb a certain amount of the kinetic energy of an impact. The experiment was applied on USCP, and the finite element model was verified experimentally. To investigate the effects of the stiffness parameters of VSCP on the specific energy absorption response (SEA_VSCP) and the area of intrusion response (S_In), response surface models fitted from design of experiment were adopted with the finite element model. In addition, a multiobjective optimization design was realized by using the global response search method and a Pareto frontier sequence was generated, which was based on the developed response surface model. It was found that the optimal value of SEA_VSCP and S_In responses cannot be achieved at the same time. Finally, a grey relational analysis is propounded to attain a desirable balance between SEA_VSCP and S_In from the Pareto frontier sequence under constraints of the peak crash force of VSCP and energy absorption of the front-end of cab car. The optimization result shows that the crashworthiness of VSCP is better than that of USCP.

Basic Study on Dynamic Reliability of Machinery and Piping System Supported by Elasto-Plastic Supports With Gaps

2015 ◽  
Author(s):  
Atsuhiko Shintani ◽  
Keishi Tsujita ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
White Noise ◽  
Energy Absorption ◽  
Analytical Model ◽  
Piping System ◽  
Basic Study ◽  
Nonlinear Characteristics ◽  
Dynamic Reliability ◽  
Vibrational Behavior ◽  
Stress Energy ◽  
Piping Systems

In this study, the vibrational behavior of piping systems supported by elasto-plastic dampers with gap supports was considered. First, an analytical model of L-type piping systems subjected to white noise was derived, including the nonlinear characteristics of the elasto-plastic dampers and gap supports. After the stress, energy absorption, and other parameters were calculated for many inputs, the dynamic reliability was calculated based on random theory. Optimization of the support locations was investigated. Finally, the effects of a gap support on the dynamic reliability were investigated.

scholarly journals Analytical Model of Wave Loads and Motion Responses for a Floating Breakwater System with Attached Dual Porous Side Walls

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Weiliang Qiao ◽  
Keh-Han Wang ◽  
Wenqi Duan ◽  
Yuqing Sun
Keyword(s):  
Analytical Model ◽  
Dynamic Responses ◽  
Body Motion ◽  
Linear Wave ◽  
Wave Loads ◽  
Vertical Side ◽  
Damping Coefficients ◽  
Floating Breakwater ◽  
Exciting Forces ◽  
Porous Walls

A set of two-dimensional analytical solutions considering the effects of diffraction and radiation are presented in this study to investigate the hydrodynamic interaction between an incident linear wave and a proposed floating breakwater system consisting of a rectangular-shaped body and two attached vertical side porous walls in an infinite fluid domain with finite water depth. The Matched Eigenfunction Expansion Method (MEEM) for multiple fluid domains is applied to derive theoretically the velocity potentials and associated unknown coefficients for wave diffraction and body motion induced radiation in each subdomain. Also, the exciting forces, as well as the added mass and damping coefficients for the floating breakwater system under the surge, heave, and pitching motions, are formulated. The displacements of breakwater motions are determined by solving the equation of motion. As a verification of the analytical model, the present solutions of the limiting cases in terms of exciting forces, moments, added masses, and damping coefficients are found to be well matched with other published numerical results. Additionally, the hydrodynamic performances and the dynamic responses in terms of Response Amplitude Operators (RAOs) of the proposed floating breakwater system are evaluated versus various dimensionless variables, such as wavelength and porous-effect parameter. The results show that the attached porous walls with selected porous properties are observed to have the advantages of reducing wave impacts on the floating breakwater system and at the same time its dynamic responses are also noticeably improved.

Development and Challenge of the Vehicle and Highway Bridges Dynamic Interaction

2013 ◽  
Vol 574 ◽  
pp. 135-150
Author(s):  
Jia Feng Liu ◽  
Yan Li
Keyword(s):  
Analytical Model ◽  
High Speed ◽  
Engineering Application ◽  
Highway Bridges ◽  
Dynamic Interaction ◽  
Dynamic Responses ◽  
Coupling Vibration ◽  
Safety Control ◽  
Main Research ◽  
Long Span

With the development of long-span flexible bridges and the increase of highway transportation, both the dynamic responses of highway bridges under high-speed and heavy vehicles and the safety control of vehicles have deserved general concerns. First, this paper briefly discussed some researches on coupling vibration of vehicle and highway-bridges, then roundly summarized main research achievements accounting on the vehicle analytical model, bridge analytical model, surface roughness of road, numerical method of vehicle-bridge coupling vibration and some other aspects. Meanwhile, some research trends and challenge on vehicle and bridge dynamic interaction in engineering application were pointed out.

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