Mathematical model validated by a crash test for studying the occupant’s kinematics and dynamics in a cars’ frontal collision

The aim of the paper was to determine the kinematic parameters that influence the occupant injury risk through a mathematical model. The developed model is a 2D model composed of 4 bodies (2 vehicles, thorax and head). The head and thorax are interconnected with a rotation joint and a torsion spring meant to stiffen the relative movement between the bodies. The thorax is connected with the vehicle body by a linear spring meant to simulate the seatbelt stiffness. The model was solved using Lagrange principle and the validation of the model was made through a crash test performed using the same initial conditions and comparing the obtained values of the displacement, velocity and acceleration parameters with the ones obtained with the mathematical model. The head and torso were chosen due to the fact that they are the common parts of the body that get injured, especially the head with the change of 80 % to cause fatal injury in car’s frontal collision. Once the model was validated, the stiffness of the seatbelt was modified in order to determine the behavior of the occupant in case of car frontal collisions. When the seatbelt stiffness was reduced, the occupant displacement and velocity increased, while by increasing the stiffness, these parameters decreased. The values of the developed model presented a high degree of similarity with the results obtained from the crash test with an error of 10 %. This model can be used by engineers to easily asses the occupant injury risk in case of vehicle frontal collisions.     

Flexural gravity wave generation by initial disturbances in the presence of current

The effect of uniform current on the generation of flexural gravity waves resulting from initial disturbances at a point was analyzed in two dimensions. The problem was formulated as an initial boundary value problem under the assumptions of the linearized theory of water waves. By direct application of the Laplace transform and then the Fourier transform, explicit expressions for the velocity potential and free surface elevation were obtained in integral forms; these were evaluated asymptotically for large distances and times by the application of the method of the stationary phase to obtain the far field behavior of the surface elevations in specific cases. Simple numerical computations were performed to illustrate the effect of uniform current on the surface elevation, wavelength, phase velocity, and group velocity of the flexural gravity waves and on the far field behavior of the progressive waves in two different cases, namely, when there is an initial depression concentrated at the origin and an initial impulse concentrated at the origin.     

LPG游船给人带来欢乐

2001年4月8日,北京昆玉河的游船(LPG船)开航了!这天不仅有文艺团体助兴演出,而且还有世纪坛、水上游系列抽奖活动,游客在欣赏沿途美景之余还会获得意外的惊喜.这是人们期待已久的了.你看吧,天蓝,水清,岸绿,船行,人笑…………     

西安地铁1号线局部线路走向的方案研究

西安地铁1号线一期工程全长25.5km,线路自西向东沿西安市东西向主客流走廊布设,但在北大街站至朝阳门站的线路偏离了西安火车站这一大型客流集散点。结合西安地铁1号线沿线客流分布及城市规划等特点,着重对北大街站至朝阳门站的线路走向方案进行了论述。通过对线路是否经过西安火车站的优缺点分析,提出了推荐的线路走向方案。     

国产内燃机车排气阀焊修后焊接过热区的脆化及使用寿命分析

本文采用焊接热模拟和时效热处理等方法处理试件,通过金相分析和性能试验,研究了内燃机车排气阀焊修后焊接过热区的脆化及其使用寿命问题.     

如何提高路基分层压实系数一次验收合格率

通过包西铁路通道陕西段路基土方填筑施工过程的实践,分析总结影响路基分层压实系数一次验收合格率的多种因素,有针对性地制定相应工程措施,指导施工生产。     

全球海上遇险与安全系统模拟器

全球海上遇险和安全系统(GMDSS-Global Maritime Distress Safety System)是国际海事组织(IMO)为改善和弥补现行海上遇险与安全通信体制所存在的缺陷和不足,最大限度地保障海上生命和财产安全而提出的一项新建议.该系统以现代先进通信技术为基础,依靠国际间的协作,组成全球统一的遇险安全通信网,保证以最小的时延自动发送/接收遇险报警,同时为紧急与安全通信提供有效的通信手段.     

SDH传输系统的告警维护信号

介绍了ＳＤＨ传输系统主要告警维护信号，描述了告警维护信号的含义和故障产生原因。举例说明了ＳＤＨ传输系统因传输故障所引起的告警序列。     

论我国高速列车的动力配置与动力转向架选型

根据京沪高速铁路的运营需求和基础设施的基本限制条件，设计了４种类型的高速列车，并经验算和分析后认为，京沪高速铁路宜采用动力分散型高速列车。通过对转向架结构和车辆联接方式的动力学性能方面的比较，建议选择体悬式万向轴传动动力转向架为列车动力转向架。同时还提出了动力架向架传动机构创新和参数选择的原则和方法。     

POLYMORPHISM OF THE vWF LOCUS AND ITS FORENSIC APPLICATION IN COMPACT BONE

Amplifiedfragmentlengthpolymorphisms(Amp--FLPs)havebeenevaluatedasusefulgeneticmarkersinforensiccaseworks{'~'].vWFpolymorphismisoneoftheAmp--FLPsdetectedbythepolymerasechainreaction(PCR).-PopulationdataconcerningvWFhasbeedpreviouslycarriedoutonEuropeanCaucasians[13.ButnodataisavailablefortheChinesepopulation.Inthisreport,wepresentthedataforvWFlocusin112unrelatedChineseHanindividualsanditsapplicabilityincompactboneanddens.MATERIALSANDMETHODS1.PrimersA:5'~ACGTATTCTATTTAT~3…