汽车安全现状与智能化仿真假人

面向汽车安全领域的智能化仿真假人技术是21世纪的尖端科技之一。论文对汽车工业安全领域发展的背景、现状进行了简单的介绍，并介绍了智能化仿真假人的发展研究现状以及其在汽车安全中发挥的重要作用，阐述了汽车碰撞事故与汽车碰撞试验的情况和机理，并最终提出了智能化仿真假人的关键技术。     

仿生皮肤材料的力学性能测试与分析

仿生皮肤材料是一种由高分子材料复合而成的,作为汽车碰撞安全性能实验假人皮肤肌肉的一种特殊功能材料。实验假人皮肤的反弹力和损伤因子影响汽车碰撞安全性能实验,影响汽车碰撞测试对人体的损伤程度判定的科学性和准确性。而仿生皮肤材料的力学性能主要受制备过程中混合基、填料的用量和硫化时间的不同等因素影响。针对汽车碰撞实验假人仿生皮肤材料的特殊性,为了制备综合性能优越的仿生皮肤,对仿生皮肤材料的制备与力学性能进行研究,研究不同混合基胶、固化剂、填料剂和后硫化时间对仿生皮肤材料力学性能的影响,通过对3种制备不同的仿生皮肤材料进行超声波测试和冲击测试分析,探讨具有最优力学性能仿生皮肤材料的合成途径。     

落锤式冲击加速度标准装置的研究与试验

一、概述随着生产实践和科学技术的发展,越来越多的领域需要对某一动态或者瞬态过程进行准确测量,而加速度传感器是广泛应用于该类测量的微机电测量系统。例如在汽车工业中,评价汽车安全性能的主要手段就是汽车碰撞试验。     

SAE J3121＿202202《氢燃料汽车碰撞试验实验室安全指南》标准解析

近年来,氢能行业不断发展。氢燃料汽车与传统内燃机汽车具有一些相同的安全特征需求,车辆需要符合厂家及政府监管的相关标准要求,而由于氢燃料汽车内部包含高压气体、高压部件等危险源,在进行碰撞等破坏性试验时具有较高的安全要求,因此SAE在2022年2月份发布了SAEJ3121＿202202《氢燃料汽车碰撞试验实验室安全指南》,旨在告知碰撞测试、设施管理等相关人员安全风险点及对应措施。本文主要解析SAEJ3121中相关技术要求,为氢燃料汽车碰撞试验提供试验流程、安全管理等相关指南方法。     

汽车撞击护栏时乘员的安全性研究

应用LS—DYNA软件，通过建立完整的三维“汽车-道路-护栏-乘员-座椅-安全带”模型，研究了汽车撞击护栏时车内乘员的安全性，得出如下重要结论：①采用完整的三维“汽车-道路-护栏-乘员-座椅-安全带”模型，能够模拟碰撞中乘员的运动与受力状态，对提高护栏的安全性设计水平有更直观的效果，对护栏评价标准的进一步发展也有重要意义，在VPC技术日益完善的今天，开展这种完整的系统研究不仅十分必要，而且切实可行；②安全带对乘员的约束大大提高了碰撞过程中乘员的安全性。分析结果表明：未系安全带的假人，不仅头部的HIC值已接近人体的耐冲击阈值，假人胸部的合成减速度峰值也偏高，且假人飞离座椅再撞击乘座室内部物体的可能性也很大，因此，一旦发生交通事故，即使是大型车辆，车内乘员的安全也将遭受严峻的考验。事实上，安全带在小型乘用车上的成功应用，大大提高了碰撞过程中乘员的安全水平，因此，在安全带日益得到推广应用的今天，在高速公路及高等级公路飞速发展的今天，是考虑大型车辆配置安全带的时候了。③在汽车撞击标准混凝士护栏的过程中，在汽车车体与混凝土护拦发生接触前即发生侧翻，亦即混凝土护栏的高度对预防汽车的侧翻基本不起作用，那种在山区公路及危险路段普遍采用标准混凝土护栏的做法并小科学，即使增加了混凝土护栏的高度也是如此；④在汽车-护栏碰撞系统CAE分析中，如果需要捕捉到车辆侧翻事故发生的可能性，则仿真的碰撞时间不宜太短，至少要超过950ms。     

汽车碰撞试验用多轴压阻加速度传感器及校准方法

通过对汽车碰撞试验用多轴加速度传感器的特性介绍,推荐了在汽车碰撞试验领域中多轴压阻式加速度传感器的选用方法。并针对汽车碰撞试验用多轴压阻式加速度传感器的计量性能结合相关标准及设备对主要校准 参数、方法做了探讨,建立了一套基于比较法为原理的校准方法。从而进一步保障汽车碰撞试验数据的准确度,提升碰撞试验的可信度。     

直升机抗坠毁试验假人下肢动力学性能的计算机仿真研究

下肢动力学性能研究是直升机抗坠毁试验假人研制过程中的重要课题。在对直升机坠撞事故中飞行员下肢损伤分析的基础上,通过建立具有我国50 th百分位飞行员参数特征的假人下肢有限元模型,按试验要求对下肢动力学性能进行仿真分析;将仿真结果分别与假人下肢动力学性能参考指标及试验结果比较,发现该下肢模型具有较好的生物拟合性,表明采用有限元法对假人下肢动力学性能分析的有效性和可行性。由于直升机坠撞事故中人体下肢损伤形式较复杂,该研究对将来能实现多方位碰撞损伤评价的假人下肢动力学性能研究具有一定指导意义,对假人其他部位动力学性能的仿真研究也具有重要参考价值。     

ISO发布世界侧面碰撞试验假人标准

ISO发布一套新的标准，为汽车业提供了最先进的碰撞试验假人，用以改善车辆设计并提高乘客的安全性。     

基于Facet模型及组合式假人对汽车-摩托车碰撞事故的仿真

为了更好的解决汽车-摩托车碰撞事故的仿真再现问题,一种新的仿真模型及方法被提出。该方法采用Facet模型建立事故汽车及摩托车的三维模型,采用组合式假人模型建立骑车人的三维模型。由Photomodeler软件得出碰撞初始条件,并利用Madymo软件对事故碰撞过程进行直观的三维仿真再现。针对一起实际的轿车与摩托车碰撞事故,采用上述仿真模型及方法进行事故模拟。仿真结果与实际事故情况可以较好吻合,人体损伤数据与法医鉴定结果可以较好吻合,从而验证了此种仿真模型及方法的可行性及有效性。     

汽车碰撞试验测量系统中定标墙的校准方法研究

碰撞试验是综合评价汽车碰撞安全性能的最基本、最有效的方法。定标墙是碰撞车辆变形测量分析系统(DMAS)重要的组成部分,是由10万多个编码点和标识点组成的一种测量空间网络,为测量系统提供标准值,从而获得汽车车身的形变。本文提出了一种汽车碰撞试验定标墙的现场校准方法,利用摄影测量系统与标准尺,通过合理布局实现定标墙的高精度校准,用该方法可将定标墙的标识点的坐标校准误差控制在0.05 mm。     

Influences of pre-crash braking induced dummy – Forward displacements on dummy behaviour during EuroNCAP frontal crashtest

Combination of active and passive safety systems is a future key to further improvement in vehicle safety. Autonomous braking systems are able to reduce collision speeds, and therefore severity levels significantly. Passengers change their position due to pre-impact vehicle motion, a fact, which has not yet been considered in common crash tests. For this paper, finite elements simulations of crash tests were performed to show that forward displacements due to pre-crash braking do not necessarily increase dummy load levels. So the influence of different pre-crash scenarios, all leading to equal closing speeds in the crash phase, are considered in terms of vehicle motion (pitching, deceleration) and restraint system configurations (belt load limiter, pretensioner). The influence is evaluated by dummy loads as well as contact risk between the dummy and the interior.     

Modeling and testing of energy absorbing lightweight materials and structures for automotive applications

As a consequence of the increasing demands in automotive industry concerning crashworthiness and passive safety, the concern for energy management and safety demands also increases. The goal of energy management is to reduce the forces and stresses on an occupant or a pedestrian during a crash event; in some cases it may be possible to reduce the forces by a factor of two. This requires usage of new advanced materials in automotive components. Energy absorbing foams and other lightweight materials like plastics and polymer composites are increasingly used in automotive industry. Hence, extensive study of energy absorbing behavior of these materials as well as the automotive components is needed for further improvements in numerical modeling and crash simulations. The paper enlightens recent advances in investigation of mechanical properties and energy absorption ability of the mentioned lightweight materials as well as modeling with finite element codes for crash simulations.     

Methods to mitigate injury to toddlers in near-side impact crashes

This research focuses on the injury potential of children seated in forward-facing child safety seats during side impact crashes in a near-side seated position. Side impact dynamic sled tests were conducted by NHTSA at Transportation Research Center Inc. (TRC) using a Hybrid III 3-year-old child dummy seated in a convertible forward/rearward child safety seat. The seat was equipped with a LATCH and a top tether and the dummy was positioned in forward-facing/near-side configuration. The test was completed using an acceleration pulse with a closing speed of 24.1 km/h, in the presence of a rigid wall and absence of a vehicle body. A fully deformable finite element model of a child restraint seat, for side impact crash investigations, has been developed which has also been previously validated for frontal and far side impacts. A numerical model utilizing a Hybrid III 3-year-old dummy, employing a similar set-up as the experimental sled test was generated and simulated using LS DYNA. The numerical model was validated by comparing the head and the chest accelerations, resultant upper and lower neck forces and moments from the experimental and numerical tests. The simulation results were observed to be in good agreement to the experimental observations. A numerical model of the near-side laboratory tests, utilizing a Q3s child dummy, was also created for parametric studies regarding different ISOFIX configurations. Further, numerical simulations were completed for both the dummy models with rectangular and cross-shaped sections of rigid ISOFIX systems. In addition, studies were conducted to confine lateral movement of the dummy's head by adding energy absorbing foam on the side wings in the vicinity of the contact region of the CRS. It was observed that the use of rigid ISOFIX system reduced the lateral displacement of the CRS and different injury parameters. Addition of energy absorbing foam blocks was effective in further reducing the lateral displacement of the dummy's head. The lateral displacement of the head was reduced by 68 mm by using cross-shaped section ISOFIX with energy absorbing foam near the vicinity of the head of the Hybrid III 3-year-old dummy compared to the flexible LATCH configuration without foam. For the Q3s dummy, the lateral displacement of the head was reduced by 48 mm by utilizing a cross-shaped section rigid ISOFIX system with the addition of energy absorbing foam compared to the flexible LATCH configuration.     

Injury potential of a three-year-old Hybrid III dummy in forward and rearward facing positions under CMVSS 208 testing conditions

This research focuses on the injury potential of children in forward and rearward facing child restraint seats in frontal collisions. Vehicle crash tests were completed following the guidelines outlined in the Canadian Motor Vehicle Safety Standard 208 using a Hybrid III three-year-old dummy in a convertible forward/rearward facing child restraint seat. The seat was equipped with a five-point restraining system and the experimental test was completed in the forward facing configuration. A numerical model employing a similar set-up as the experimental crash test was developed and numerically simulated using LS-DYNA. To verify the numerical simulations, the head and chest accelerations as well as neck loads and moments were compared to the experimental findings and it was observed that a reasonable correlation between the experimental and numerical observations existed. Further numerical simulations were completed to investigate the influence of positioning the three-year-old dummy in the rearward configuration on the head and neck injury potential during frontal crash. Through an analysis of injury criteria, using neck loads and head accelerations, it was observed that the rearward facing child dummy sustained significantly lower levels of neck injury criteria while exhibiting similar levels of the head injury criteria as the forward facing child dummy.     

高强度钢性能及其在车身中的应用

在汽车轻量化与提高碰撞安全性能的基础上,首先简单介绍了汽车常用钢和汽车用高强度钢种类,并简述了几种常用高强度钢的强化机制和性能,概述了2种高强度钢的成形工艺,指出了其在成形时存在的问题以及改善其成形性的措施.介绍了高强度钢在汽车车身中的应用情况,展望了高强度钢在未来车身中的应用前景.大量采用高强度钢在加快汽车轻量化进程和提高汽车碰撞安全性能方面有重大作用.     

A numerical investigation into the effect of CRS misuse on the injury potential of children in frontal and side impact crashes

This research focuses on an investigation into the head and neck injuries sustained by toddlers due to CRS misuse under frontal and side impact crashes. A fully deformable FE model incorporating a Hybrid III 3-year-old dummy was developed which has been previously validated for frontal impacts under CMVSS 208 and FMVSS 213 testing conditions. Furthermore, this model has also been validated under near-side impact conditions in accordance to crash tests carried out by NHTSA. In addition, numerical models incorporating a Q3/Q3s prototype child crash test dummies were developed. The objective of this research was to study the effect of seatbelt slack and the absence of the top tether strap on the head and neck injuries sustained by toddlers in a vehicle crash. Numerical simulations were conducted under full frontal and near side impact crash testing conditions in accordance with FMVSS 213 for the Hybrid III 3-year-old dummy and Q3/Q3s dummies in the absence and presence of slack in the seatbelt webbing, and in the absence and presence of the top tether strap. In addition, the effect of using a cross-shaped rigid ISOFIX system was also investigated. An analysis of the head and chest accelerations, neck loads and moments was completed to investigate the potential of injury due to CRS misuse. An increase in HIC₁₅ by approximately 30–40% for the frontal impact and 10–20% for the near-side impact respectively was observed for the Q3 child dummy due to both forms of CRS misuse. In the absence of the top tether strap the forward head excursions were observed to be increased by approximately 70% for the Hybrid III 3-year-old dummy and 40% for the Q3 dummy, respectively. Use of the cross-shaped rigid ISOFIX system illustrated a reduction in head and neck injury parameters, for both frontal and side impact conditions, in the absence and presence of CRS misuse. CRS misuse results in a significant increase in injury parameters and potential for contact related head injuries. Use of a rigid ISOFIX system to restrain a CRS provides better CRS and dummy confinement and reduced injury potential than a flexible ISOFIX system.     

Accessory child safety harnesses: Do the risks outweigh the benefits?

Accessory child safety harnesses are available in some countries as alternative restraints for young children or as an accessory restraint used with booster seats. Their use, in Australia at least, is becoming more common. There have been concerns that the risk of misuse of these restraints outweighs any potential benefit this system might have over a retractable lap-shoulder belt system used with a booster seat. However to date there is no evidence to confirm or deny this. This study used laboratory simulated frontal crash tests to examine the performance of accessory child safety harness systems compared to the lap-shoulder belt when used alone and when used with two common designs of Australian booster seat. The performance of the child safety harness system when misused was also investigated. The results demonstrate that the correctly used child safety harness system performed no better than the lap-shoulder system, and in fact allows for a greater risk of submarining. Furthermore, one common form of child safety harness misuse, where the harness is over-tightened causing the lap belt to be positioned high over the abdomen, allowed extremely undesirable dummy motion. This involved gross submarining and direct contact between the harness system and the dummy's neck. These findings suggest that the risks associated with accessory child safety harness systems most likely outweigh any potential benefits, in frontal impacts at least.     

Motorcycle safety device investigation: A case study on airbags

The present standard for assessing the effectiveness of safety measures for motorcycle riders defined in ISO 13232 is unique and it incorporates evaluation by computer simulation supplemented by full-scale crash tests. This report describes the process of using FE (Finite Element) simulations to investigate safety options for motorcycle riders. The experience of developing finite element models acceptable as per ISO 13232 standards has been described. The variation in dummy head accelerations on impact with inflating airbags has been studied in an environment acceptable as per ISO 13232 standards. Based on the simulations, it may be concluded that inflating airbags in motorcycles do not pose a significant injury threat.     

Robust design of an interior hard trim to improve occupant safety in a vehicle crash

Head injury ranks among the top contributors in automobile accidents. Consequently, although styling is treated important, safety of occupants in a crash receives preemptive priority in the design of automotive interior components. Additionally, the Federal Motor Vehicle Safety Standard (FMVSS) 201 has laid down certain requirements to be fulfilled by automobile manufacturers for producing a safe vehicle. One of the requirements stipulate dummy equivalent of the Head Injury Criteria, i.e. HIC(d) value for the interior components of a vehicle to be below 1000 under certain stated conditions. In this paper, we provide a robust design approach to achieve the requirements for one such interior component, viz. an interior hard trim that covers the pillar closest to the driver's head on the left-hand side of the vehicle.     

Computational and experimental crash analysis of the road safety barrier

The paper describes the computational analysis and experimental crash tests of a new road safety barrier. The purpose of this research was to develop and evaluate a full-scale computational model of the road safety barrier for use in crash simulations and to further compare the computational results with real crash test data. The impact severity and stiffness of the new design have been evaluated with the dynamic nonlinear elasto-plastic analysis of the three-dimensional road safety barrier within the framework of the finite element method with LS-DYNA code. Comparison of computational and experimental results proved the correctness of the computational model. The tests have also shown that the new safety barrier assures controllable crash energy absorption which in turn increases the safety of vehicle occupants.