新型车载医疗救护隔振平台设计及仿真

车载医疗救护隔振平台是一种以车辆为载体的伤病员专用救护装备。为了最大程度地避免伤病员在运送中因车辆振动而造成的二次伤害,获得最佳减振效果,设计了一款新型车载医疗救护隔振平台,它具有大长宽比、多层串联的结构特点。为了获得该平台的关键隔振参数,建立了隔振平台的物理模型,并采用基于分析力学的拉格朗日法建立了平台的状态方程,应用MATLAB软件对在典型激励作用下的隔振参数进行了优化,得到了最优的平台减振弹簧刚度和阻尼。最后,为了研究该新型隔振平台在车辆运行过程中的减振效果,建立了基于被动悬架的隔振平台全系统动力学模型,并采用ADAMS软件仿真分析了在斜坡路面和正弦起伏路面两种典型激励下的隔振平台的输出响应。结果表明,该隔振平台能够极大地衰减来自地面的冲击和振动,尤其对于恶劣路况,其减振效果更佳。该隔振平台结构及参数设计符合工程实际,所采用的优化方法和全系统建模及仿真方法正确、有效。     

Reliability approach for vehicle safety components

Owing to ‘producer's liability for defective products’ the safety-related components of vehicles have to be designed, tested and manufactured in an appropriate way. Some considerations are presented about useful procedures in design and testing of safety parts which may help to reach the required high reliability and minimize risks. Problem areas are indicated which need more research. In future the reliability approach in automotive industries will come closer to the standards in aeronautics. This trend is accelerated by the rapid use of electronics in automobiles.     

车台用角位移传感器自动分度校准系统设计

为实现高精度SJJF型数显手动分度头的数控化改造应用,满足某航空发动机整机性能测试中车台用角位移传感器自动校准检测的实用性需求,解决手工角度分度耗时费力的难题,提出了角度量自动分度控制系统设计方案,运用逻辑可编程器件（Programmable Logic Controller,PLC）配合专用梯形图编程指令,实现角度光栅信号自动数字化采集、角度值换算、比例微分积分闭环控制（Proportion Integration Differentiation Controller,PID）定位及光栅对零,能够有效满足车台用角位移传感器线性度、灵敏度等校准精度要求,且节约了70%的时间,提高角度分度效率的同时也降低了劳动强度。     

汽车前纵梁吸能盒结构耐撞性多目标优化

吸能盒上诱导槽的分布形式对汽车碰撞性能有很大影响.以汽车前纵梁吸能盒结构为对象,建立整车正面碰撞仿真模型,对吸能盒结构的耐撞性进行了多目标优化设计.以吸能盒上诱导槽之间的间距为设计变量,使用Hammersley方法采集样本点后,以车辆吸能盒的最大吸能量E、最大刚性墙反力F以及车身最大加速度a为目标函数,通过krigin...     

Car occupant safety in frontal crashes: a parameter study of vehicle mass, impact speed, and inherent vehicle protection

A new mathematical model was developed to estimate average injury and fatality rates in frontal car-to-car crashes for changes in vehicle fleet mass, impact speed distribution, and inherent vehicle protection. The estimates were calculated from injury/fatality risk data, delta-V distribution and collision probability of two vehicles, where delta-V depends on impact speed and mass of the colliding vehicles. The impact speed distribution was assumed to be unaffected by a change in fleet mass distribution.

The results showed that safety in frontal crashes would improve 27–35% by a 10% increase in fatality risk parameters, which reflected substantial improvement in inherent vehicle protection. A 40% safety improvement was attained by a 10% impact speed reduction. Consequences of vehicle fleet mass were not as strong, but depended on the average mass ratio of the fleet. A reduction in mass range would be the most beneficial, while a uniform mass reduction of 20% would increase the fatality rate by 5.4%. The model estimates trends in traffic safety and may help to identify priorities in active and passive safety.     

A road safety performance indicator for vehicle fleet compatibility

This paper discusses the development and the application of a safety performance indicator which measures the intrinsic safety of a country's vehicle fleet related to fleet composition. The indicator takes into account both the ‘relative severity’ of individual collisions between different vehicle types, and the share of those vehicle types within a country's fleet. The relative severity is a measure for the personal damage that can be expected from a collision between two vehicles of any type, relative to that of a collision between passenger cars. It is shown how this number can be calculated using vehicle mass only. A sensitivity analysis is performed to study the dependence of the indicator on parameter values and basic assumptions made. The indicator is easy to apply and satisfies the requirements for appropriate safety performance indicators. It was developed in such a way that it specifically scores the intrinsic safety of a fleet due to its composition, without being influenced by other factors, like helmet wearing. For the sake of simplicity, and since the required data is available throughout Europe, the indicator was applied to the relative share of three of the main vehicle types: passenger cars, heavy goods vehicles and motorcycles. Using the vehicle fleet data from 13 EU Member States and Norway, the indicator was used to rank the countries’ safety performance. The UK was found to perform best in terms of its fleet composition (value is 1.07), while Greece has the worst performance with the highest indicator value (1.41).     

Passenger vehicle safety in Australasia for different driver groups

Vehicle fleets in developed countries have benefitted from improved technology and regulation leading to safer vehicles. Nevertheless, for various reasons the public do not necessarily choose particular makes and models of cars according to their safety performance. This study aimed to identify areas for potential crashworthiness improvement in the Australasian fleets by studying the distribution of these fleets according to vehicle age and estimated crashworthiness. We used an existing database that encompassed the vast majority of the crash fleets studied, with existing estimates of crashworthiness generated by the Australasian Used Car Safety Ratings project. There were clear tendencies for older and younger people to be driving less safe vehicles that were also generally older. Given that older drivers are more fragile, and hence more liable to be injured in crashes, and younger drivers have a greater propensity to crash, it is clearly undesirable that these driver groups have the least crashworthy vehicles. Some suggestions are made to encourage safer vehicle choices.     

基于概率-凸集混合模型的汽车正面碰撞结构可靠性优化设计

本文基于概率和凸集模型研究汽车正面碰撞可靠性优化设计问题。根据汽车吸能结构厚度、材料参数等不确定参数类型,分别采用概率和多椭球凸模型进行描述,以汽车正面碰撞安全性可靠性指标为约束,考虑汽车吸能结构质量为优化目标,建立了一种基于混合模型的可靠性优化设计模型。采用拉丁方试验设计构造了目标函数和约束函数的Kriging近似模型,利用功能度量法求解可靠度指标值,通过基于移动因子序列优化与可靠性评定将嵌套优化解耦为单层次优化。实际算例表明算法具有较高的计算效率及精度,对实际设计工作有一定参考价值。     

地铁A型车辆转向架设计

本文主要介绍了适用于地铁A型车辆的A型车转向架的整体结构、主要技术特点和技术参数,构架、车轴、车轮等重要部件的技术特点及强度计算结果,整车动力学性能计算结果。各项计算结果均满足标准要求。     

CCD激光自准直系统测光电经纬仪车载平台变形

车载平台变形是影响光电经纬仪跟踪精度的关键因素,提出了利用CCD激光自准直测量系统来测量车载平台变形的新方法。用CCD系统采集车载平台的变形视频信号,计算机对视频信号进行处理得到脱靶量数据,由此即可算出车载平台变形量。实验数据分析结果表明,车载平台变形量随着速度和加速度呈周期性变化,变形曲线的趋势与加速度曲线的趋势相同。当经纬仪以60°/s速度引导工作时,方位最大变形为12.57″,高低最大变形为5.98″。这种方法为进一步研究反馈补偿以提高经纬仪的跟踪精度提供了理论依据。     

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.     

高压储能电容测试平台的设计

为解决高压电容生产企业的电容性能测试试验需求,提高产品的合格率和改进生产工艺,设计了高压储能电容器的质量试验和耐压试验测试平台主回路,并成功研制了一个多功能高压电容器测试试验平台.系统以FPGA为数字控制平台,采用状态机实现逻辑控制,实现系统在复杂环境下的可靠工作.通过设定测试平台的参数,可以针对不同容量的电容器进行不同电压、频率以及放电电流情况下的质量试验和耐压试验.目前,该测试平台已在某企业投入使用,其工作稳定、可靠,很好地满足了企业的生产测试需求.     

MMIC's for an integrated RF spectrum analyzer front end

The monolithic microwave IC (MMIC) approach for the front end of an RF spectrum analyzer improves interconnection problems due to direct access to a device-under-test (DUT). This paper proposes and demonstrates novel MMIC's for a probe-type, 1-32 GHz spectrum analyzer (SPA) front end. The MMIC's are an up-converter, a variable attenuator, a switch, and a down-converter. This MMIC set utilizes novel FET cells for impedance matching, signal combinations, isolation, and impedance translation to achieve an ultra-wideband performance as well as a remarkable size reduction in an SPA front end     

Analysis of failure of add-on armour for vehicle protection against ballistic impact

The deployment of peacekeeping forces in conflict areas has shown that some armour systems are not sufficient to meet the latest threats.This applies particularly to lightweight vehicles whose armours give protection only against low calibre ammunitions.The development, production and fielding of add-on armours gives the answers to the demand for mission adjustable protection systems.Add-on armours represent a new protection philosophy, because they are produced as a separate kit, designed to achieve different protection levels. They have several advantages: Separate transport of armour and vehicle, they can be screwed to the main skull structure by crews and they are easily repairable or upgraded.Advanced add-on armours are produced by a clever combination of ceramic tiles backed by metal or composite plates.The utilization of advanced ceramics began in the 1960s when the US Army was demanding lightweight body armours for helicopter crews. Nowadays a wide spectrum of advanced ceramics is currently used for armour production, including alumina, silicon carbide, titanium diboride and boron carbide.Ceramics possess a high protection potential due a moderate density combined to a high compressive strength. But they are too brittle to be used without a ductile material backing.The design of ceramic add-on armours is a difficult task due to the high number of parameters involved: material selection, thicknesses of different materials, impact obliquity, etc. A design based exclusively on experimental tests is therefore expensive in money and time.This paper summarizes the utilization of analytical and numerical computation of ceramic/metal and ceramic/composite add-on armour failure process as valuable tools for armour design optimisation. Some examples are presented showing a good agreement between analytical, numerical and experimental results of residual mass and residual velocity of kinetic energy projectiles after perforation of the add-on armour.     

Risk factors for pelvic fractures in lateral impact motor vehicle crashes

Lateral impact motor vehicle crashes account for over 10% of all crashes and are more likely to result in pelvic fractures than frontal crashes. We performed a case control study of lateral impact motor vehicle crashes using the 1995-2004 National Accident Sampling System Crashworthiness Data System to determine occupant and vehicle risk factors for pelvic fractures. Cases (N=728) were occupants involved in a near-side lateral impact crash who experienced a pelvic fracture and controls were occupants (N=5710) who did not experience a pelvic fracture. Occupant risk factors evaluated were age, body mass index (BMI), gender including pregnancy status, and seat belt use. Vehicle risk factors evaluated were vehicle body type, weight of striking and struck vehicles, and magnitude of intrusion of side or door panel. Using multivariate logistic regression analysis, we found that age 65 years or older, female gender, underweight body mass index, and increasing magnitude of intrusion of the door or side panel of the vehicle were associated with an increased risk of a pelvic fracture. Injury prevention strategies should focus on decreasing the magnitude of side or door panel intrusion to decrease the risk of pelvic fracture in the event of a lateral impact crash.     

Impact characteristics of a vehicle population in low speed front to rear collisions

Rear impact collisions are mostly low severity, but carry a very high societal cost due to reported symptoms of whiplash and related soft tissue injuries. Given the difficulty in physiological measurement of damage in whiplash patients, there is a significant need to assess rear impact severity on the basis of vehicle damage. This paper presents fundamental impact equations on the basis of an equivalent single vehicle to rigid barrier collision in order to predict relationships between impact speed, maximum dynamic crush, mean and peak acceleration, time to common velocity and vehicle stiffness. These are then applied in regression analysis of published staged low speed rear impact tests. The equivalent mean and peak accelerations are linear functions of the collision closing speed, while the time to common velocity is independent of the collision closing speed. Furthermore, the time to common velocity can be used as a surrogate measure of the normalized vehicle stiffness, which provides opportunity for future accident reconstruction.     

某前驱车轮端起步粘滑异响分析与控制

某前驱车型在起步过程中驱动轮端出现"咔哒"异响,问题发生频次较高,严重影响整车品质。对异响现象进行分析最终确定是轮毂轴承与驱动半轴接触端面粘滑振动引起,在粘滑过程中接触端面由静摩擦向滑动摩擦转变时接触面间摩擦系数突变产生轴向冲击力诱发异响。通过建立合理的物理模型,分析粘滑运动过程中相关的正压力、滑动摩擦系数、静摩擦系数等参数的影响,利用一种特制减摩垫圈,进而改变传动零部件接触端面的动态摩擦特性,有效解决了该车型驱动轮端起步异响的问题。目前,国内外针对车辆传动系统中粘滑摩擦的研究较少。该研究对新车型传动设计过程中类似的粘滑异响处理有积极的借鉴和参考意义。     

一种AT91RM9200嵌入式开发平台设计

介绍了一种基于ARM9内核的工业级AT91RM9200芯片的嵌入式开发平台设计。重点讨论了硬件设计方案并给出了详细的开发流程。通过采用核心板＋扩展板的硬件架构，使用现场可编程逻辑器件扩展系统功能及接口，使得本系统既适合于初学者也适合于项目开发。通过例子使用者可以快速掌握系统架构，并具有建立基于ARM9内核芯片嵌入式系统设计的能力。系统还扩展了GPIB接口便于与通用测试仪器相连。     

Radiation safety impact for top-up operation at the NSRRC

Radiation safety impact for the upcoming top-up operation at the National Synchrotron Radiation Research Center (NSRRC) has been investigated with emphasis on the consequence of injection efficiency. Keeping the storage ring at high stored current by frequent injections, the top-up operation will inevitably increase the radiation dose compared with that in the present decay mode, especially when the injection efficiency is low. In addition, significantly high level of radiation could stream through the ratchet wall openings during top-up injections while shutters are open. Therefore, a series of radiation safety analyses including calculations and measurements have been carried out to assess the feasibility of this mode on the prospective radiation protection. The paper summarises the evaluation and the corresponding action plans for radiation safety.