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Frontal crash Analysis of a Fully Detailed Car Model Based on Finite Element Method

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上海交通大学学报 2004年第z2期38卷 136-141页

作者： Han Shan-Ling Zhu Ping Lin Zhong-Qin Shi Yu-Liang School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China

This paper sets up a highly detailed finite element model of a car for frontal crashworthiness applications, and then explains the characteristics of it. The geometry model is preprocessed by Hypermesh software. The finite element method solver program selected for the simulation is LS-DYNA. After the crash simulation is carefully analyzed, the frontal crash experiment is aimed to validate the finite element model. The simulation results are basically in agreement with the experimental results. The validation of the finite element model is crucial for the further research in optimization of the automotive structure or lightweighting of the vehicle.

关键词： finite element method frontal crash LS-DYNA

Real-time rear-end crash potential prediction on freeways

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Journal of Central South University 2017年第11期24卷 2664-2673页

作者： QU Xu WANG Wei WANG Wen-fu LIU Pan School of Transportation Southeast University Civil Engineering Department University of Waterloo

This study develops new real-time freeway rear-end crash potential predictors using support vector machine(SVM) technique. The relationship between rear-end crash occurrences and traffic conditions were explored using historical loop detector data from Interstate-894 in Milwaukee, Wisconsin, USA. The extracted loop detection data were aggregated over different stations and time intervals to produce explanatory features. A feature selection process, which addresses the interaction between SVM classifiers and explanatory features, was adopted to identify the features that significantly influence rear-end crashes. Afterwards, the identified significant explanatory features over three separate time levels were used to train three SVM models. In the end, the multi-layer perceptron(MLP) artificial neural network models were used as benchmarks to evaluate the performance of SVM models. The results show that the proposed feature selection procedure greatly enhances the accuracy and generalization capability of SVM models. Moreover, the optimal SVM classifier achieves 81.1% overall prediction precision rate. In comparison with MLP artificial neural networks, SVM models provide better results in terms of crash prediction accuracy and false positive rate, which confirms the superior performance of SVM technique in rear-end crash potential prediction analysis.

关键词： freeway rear-end crash crash potential prediction crash precursors case control strategy support vector machine

Will crash Experience Affect Driver’s Behavior? An Observation and Analysis on Time Headway Variation Before and After a Traffic crash

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Tsinghua Science and Technology 2020年第4期25卷 471-478页

作者： Yun Yue Zi Yang Xin Pei Hongxin Chen Chao Song Danya Yao Department of Automation Tsinghua UniversityBeijing 100084China National Engineering Laboratory for Public Safety Risk Perception and Control by Big Data(PSRPC) China Academy of Electronics and Information TechnologyBeijing 100041China

Research into the impact of road accidents on drivers is essential to effective post-crash ***,due to limited data and resources,the current research focus is mainly on those who have suffered severe *** this paper,we propose a novel approach to examining the impact that being involved in a crash has on drivers by using traffic surveillance *** traffic video surveillance systems,the locations of vehicles at different moments in time are captured and their headway,which is an important indicator of driving behavior,can be calculated from this *** was found that there was a sudden increase in headway when drivers return to the road after being involved in a crash,but that the headway returned to its pre-crash level over *** further analyzed the duration of the decay using a Cox proportional hazards regression model,which revealed many significant factors(related to the driver,vehicle,and nature of the accident)behind the survival time of the increased *** approach is able to reveal the crash impact on drivers in a convenient and economical *** can enhance the understanding of the impact of a crash on drivers,and help to devise more effective re-education programs and other interventions to encourage drivers who are involved in crashes to drive more safely in the future.

关键词： crash impact driving behavior time headway survival time Cox proportional hazards model

Investigating the relationship between crash severity,traffic barrier type,and vehicle type in crashes involving traffic barrier

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第1期7卷 125-136页

作者： Amirarsalan Mehrara Molan Mahdi Rezapour Khaled Ksaibati Department of Civil and Environmental Engineering California Polytechnic State UniversitySan Luis ObispoCA 93407USA Wyoming Technology Transfer Center Department of Civil and Architectural EngineeringUniversity of WyomingLaramieWY 82071USA

Roadside safety is one of the important components of highway systems due to its considerable rate of high-severity *** barriers play a key role in reducing the crash severity and saving more lives on roadsides but choosing an inappropriate traffic barrier could decrease traffic barriers’*** paper investigated the variables affecting crash severity in different traffic barrier types(cable,guardrail,and rigid)and vehicle types(truck,and non-truck).For this purpose,an ordinal logistic regression approach was conducted on the crash data collected between 2007 and 2016 in *** to the results,different traffic barrier types show different relationships to crash severity based on posted speed limit at the *** guardrail segments,a high-severity crash is more likely when the posted speed limit is more than 55 mph;however,cable barrier crashes were less severe in high-speed limit(>55 mph)*** light vehicles were more vulnerable to crashes hitting rigid barriers,no significant difference was found between performances of cable and rigid barriers in terms of truck crash *** analytical models proposed in this study would make a clear view for designers and decision-makers in selecting the most appropriate traffic ***,the effective factors introduced in each model could be used to rank the risk posed by existing traffic barrier segments based on traffic barrier type,truck volume percentage,and other highway characteristics.

关键词： Traffic barrier Roadside safety Truck crash severity Ordinal logistic regression Wyoming

The Emergency Department crash Cart: A systematic review and suggested contents

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World Journal of Emergency Medicine 2018年第2期9卷 93-98页

作者： Gabrielle A.Jacquet Bachar Hamade Karim A.Diab Rasha Sawaya Gilbert Abou Dagher Eveline Hitti Jamil D.Bayram Department of Emergency Medicine Boston University School of Medicine Center for Global Health and Development Boston University School of Public Health Department of Critical Care Medicine University of Pittsburgh Medical Center Department of Pediatrics Rush University Medical Center Department of Emergency Medicine American University of Beirut Medical Center

BACKGROUND: As the field of Emergency Medicine grows worldwide, the importance of an Emergency Department crash Cart(EDCC) has long been recognized. Yet, there is paucity of relevant peer-reviewed literature specifically discussing EDCCs or proposing detailed features for an EDCC suitable for both adult and pediatric patients. METHODS: The authors performed a systematic review of EDCC-specific literature indexed in Pubmed and Embase on December 20, 2016. In addition, the authors reviewed the 2015 American Heart Association(AHA) guidelines for cardiopulmonary resuscitation and emergency cardiovascular care, the 2015 European Resuscitation Council(ERC) guidelines for resuscitation, and the 2013 American College of Surgeons(ACS) Advanced Trauma Life Support(ATLS) 9 th ***: There were a total of 277 results, with 192 unique results and 85 duplicates. After careful review by two independent reviewers, all but four references were excluded. None of the four included articles described comprehensive contents of equipment and medications for both the adult and pediatric populations. This article describes in detail the final four articles specific to EDCC, and proposes a set of suggested contents for the EDCC. CONCLUSION: Our systematic review shows the striking paucity of such a high impact indispensable item in the ED. We hope that our EDCC content suggestions help enhance the level of response of EDs in the resuscitation of adult and pediatric populations, and encourage the implementation of and adherence to the latest evidence-based resuscitation guidelines.

关键词： Resuscitation crash cart Emergency department

Grey Relational Analysis Coupled with Principal Component Analysis Method For Optimization Design of Novel crash Box Structure

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Journal of Beijing Institute of Technology 2019年第3期28卷 577-584页

作者： Shuang Wang Dengfeng Wang State Key Laboratory of Automotive Simulation and Control Jilin University

crashworthiness and lightweight optimization design of the crash box are studied in this paper. For the initial model, a physical test was performed to verify the model. Then, a parametric model using mesh morphing technology is used to optimize and decrease the maximum collision force (MCF) and increase specific energy absorption (SEA) while ensure mass is not increased. Because MCF and SEA are two conflicting objectives, grey relational analysis (GRA) and principal component analysis (PCA) are employed for design optimization of the crash box. Furthermore, multi-objective analysis can convert to a single objective using the grey relational grade (GRG) simultaneously, hence, the proposed method can obtain the optimal combination of design parameters for the crash box. It can be concluded that the proposed method decreases the MCF and weight to 16.7% and 29.4% respectively, while increasing SEA to 16.4%. Meanwhile, the proposed method in comparison to the conventional NSGA-Ⅱ method, reduces the time cost by 103%. Hence, the proposed method can be properly applied to the optimization of the crash box.

关键词： crash box optimization maximum collision force (MCF) specific energy absorption (SEA) grey relational analysis (GRA) principal component analysis (PCA)

The verbiage in variable message signs and traffic diversion during crash incidents

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Journal of Intelligent and Connected Vehicles 2022年第3期5卷 333-344页

作者： Sailesh Acharya Michelle Mekker Department of Civil and Environmental Engineering Utah State UniversityLoganUtahUSA

Purpose–WIth limited research on the effects of variable message sign(VMS)message content and verbiage on revealed driver behavior,this study aims to investigate how different verbiage of crash-related messages are related to the diversion ***/methodology/approach–Using ordered logit models,the associations of message verbiage with diversion rates during crash incidents were assessed using five years of VMS message history within a section of I-15 in the state of ***–A significant impact of message verbiage on the diversion rate was *** on the analysis results,the crash message verbiage with the highest diversion was found to be miles to crash 1“prepare to stop,”followed by crash location 1 delay information,miles to crash 1“use caution”1 lane of the crash,*** addition,the diversion rate was found to be correlated to some roadway characteristics(*** in mainline,weather condition and light condition)along with the temporal *** limitations/implications–These findings could be used by transportation agencies(*** department of transportation[DOTs])to make informed decisions about choosing the message verbiage during future crash *** study also revealed that higher diversion rates are associated with a shorter distance between the crash location and VMS device location,recommending increasing the number of VMS devices,particularly in crash-prone areas.

关键词： Variable message sign Verbiage message content diversion rate crash Driver behavior Congestion

Religion and stock price crash risk:Evidence from China

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China Journal of Accounting Research 2016年第3期9卷 235-250页

作者： Wenfei Li Guilong Cai Sun Yat-sen Business School Sun Yat-sen University

This paper investigates whether religious traditions influence firm-specific crash risk in *** a sample of A-share listed firms from 2003 to 2013,we provide evidence that the more intense the religious environment,the lower the stock price crash risk,implying that religion plays an important role in Chinese corporate ***,we find that(1) religion affects stock price crash risk by reducing earnings management and the management perk problem;(2) different religions have different effects,and Taoism,in particular,is unrelated to crash risk; and(3) the effects of religion are more pronounced with higher quality corporate governance and a stronger legal *** constrains the management agency problem,thus reducing stock price crash risk in *** paper enriches the literature on stock price crash risk and religion,and on new economic geography.

关键词： Religious environment Stock price crash risk Informal institution Corporate governance

Employee stock ownership plan and stock price crash risk

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Frontiers of Business Research in China 2019年第3期13卷 251-283页

作者： Yan Li Bao Sun Shangyao Yu Business School Renmin University of ChinaBeijing 100872China Business School Beijing Technology and Business UniversityBeijing 100048China

This paper examines whether the announcement of an employee stock ownership plan(ESOP)affects stock price crash risk and the mechanism by which the ESOP may influence crash risk,using a sample of Chinese A-share firms from the period 2014 to *** provide evidenee that an ESOP announcement is significantly and negatively related to a firm's stock price crash *** ESOP announcement sends positive signals to the market that insiders are optimistic about a firmzs future value,which helps enhance investor confidence,resist the pressure for a fire sale caused by negative information disclosure,and reduce stock price crash *** research shows that larger-scale,lower-priced and non-leveraged ESOPs are more helpful in reducing crash *** paper sheds lights on the impact of ESOPs in a volatile market environ *** also contributes to firms' implementatio n of ESOPs and the development of the legal system in capital markets.

关键词： Employee stock ownership plan(ESOP) crash risk Market situation Signaling effect Leveraged ESOP China