救护车卧姿伤病员受振舒适性的评价研究

通过１３名男女志愿受试者在ＭＴＳ电液振动驯卧姿承受振动的试验研究，得到了１－３２Ｈｚ频率范围内的“１分钟卧姿人体承受垂直方向全身振动的‘舒适性降低’界限曲线”。以该曲线为基础，结合卧姿人体受振响应及汽车振动的特点，提出 相应的测试及评价方法。     

卧姿人体垂直振动模型的研究

对卧姿人体垂直振动模型进行研究,计算和评价卧姿人体承受振动的舒适性,对于卧铺及救护车辆的设计有参考及指导意义。文中利用动力学手段,采用机械阻抗相等的方法进行模拟,将卧姿人体等效为由质量、弹簧、阻尼等机械元件组成的等效系统。着重考虑头部、胸部、腹部等对振动冲击的敏感部位,对5名受试者进行了卧姿自由、约束两种状态下的试验,最后利用所得的加速度阻抗特性曲线对模型进行了验证。     

救护车卧姿乘员受振舒适性的评价研究

为合理地分析和评价救护车卧姿乘员的受振舒适性，开展了卧姿人体全身振动暴露的舒适性试验研究。通过对１３名志愿受试者３００多人次的试验，得到了卧姿人体全身振动暴露１ｍｉｎ降低舒适性的阈限，并据此导出了１６ｍｉｎ、２５ｍｉｎ、１ｈ、２．５ｈ、４ｈ、８ｈ、１６ｈ和２４ｈ对应的降低舒适性界限。建立了相应的舒适性评价方法，将其应用于某野战急救车的卧姿舒适性评价，取得了较好的效果。     

卧姿乘员受振实验及救护车舒适性的评价

为合理地分析、评价救护车卧姿乘员的受振舒适性，进行了卧姿人体全身振动暴露的舒适性实验研究。通过１３名志愿受度者三百多人次的实验，得到了卧姿人体全身振动暴露１ｍｉｎ降低舒适性的阈限，并据此导出了１６ｍｉｎ、２５ｍｉｎ、１ｈ、２．５ｈ、４ｈ、８ｈ、１６ｈ、２４ｈ对应的降低舒适性界限；建立了相应的舒适性评价方法，将其应用于某野战急救车的乘卧车舒适性评价，取得了较好的效果。     

卧姿人体承受全身振动的试验方法研究

在总结人体承受全身振动研究的基础上，指出研究卧资人体承受全身振动的意义，分别讨论了在卧资人体承受全身振动的试验研究过程中，把人体作为机械系统用物理指标评价，把人体作为生物系统用生理指标评价；把人体作为具有复杂思维能力的思想系统，用心理指标评价的试验评价方法和评价指标体系。     

卧姿人体频响函数的测量和分析

６名卧姿受试者承受频率为１－３１．５ＨＺ的正弦扫频垂直振动及俯振动，以振动床面加速度信号为输入，以人体头，胸，腹，腿及头部水平等５点加速度信号输出，经测试及数据处理，获得各部位频率响应曲线，并对人体不同部位的响应特性进行分析。     

公路卧铺客车卧姿人体振动研究

通过分析公路卧铺客车卧姿人体振动，建立7自由度振动系统模型，模拟计算在前后轮路面不平度随机输入作用下，卧姿人体头、臂、腿三个部位的频率响应，并与道路试验结果进行比较。     

卧姿人体全身振动暴露舒适性降低界限的实验研究

本文介绍试验中采用心理应变评价的“五级十分法”，同时兼顾生理指标的变化，确定了受试者在各频率点达到舒适性降低界限时的振动加速度阈值，对其作统计处理并进行规范化，获取了“卧姿人体全身振动暴露１ｍｉｎ的舒适性降低界限”。     

救护车担架—卧位人体系统振动的最优主动控制研究

本文采用域计权形式二次型性能指标函数，研究了救护车担架－卧位人体系统振动的最优主动问题。研究结果表明，与传统的被动隔振系统相比，担架主动隔振系统能旬有效地降低担架－卧位人体系统垂直振动和纵向角振动加速度的均方根值；在性能指标中采用与频率相关的计权矩阵，可进一步降低系统在相应频带的振动。本文为改善救护车卧姿伤病员的运送平顺性提供了一个新的思路和方法。     

基于整车模型的路面不平度与行车舒适性关系的分析

鉴于目前尚未建立统一的行车舒适性的评价标准,通过建立符合车辆实际振动情况的十自由度整车模型,并以此模型为分析基础,以ISO2631—1：1997（E）《人体承受全身振动的评价标准》为依据,分析了路面不平度与行车舒适性的关系,评价了A、B、C三种等级路面的不平度对行车舒适性的影响,阐述了应从舒适性的角度对路面不平度分级进行调整的原因。     

平地机振动舒适性的测试与评估

介绍了国际标准ISO 2631和欧共体人体安全委员会法规89/391/EC有关车辆座椅振动的测试、分析和评估方法,对平地机在现场作业和路面行驶工况下的振动进行了测试和分析,并以试验中振动最严重的工况为例,按照ISO2631和89/391/EC对平地机振动舒适性及振动对人体健康的影响进行了分析评估。最后,对如何改善平地机的整车动态性能,提高座椅舒适性提出了建议。     

Multi-performance analyses and design optimisation of hydro-pneumatic suspension system for an articulated frame-steered vehicle

This study investigates the coupled ride and directional performance characteristics of an articulated frame-steered vehicle (AFSV). A three-dimensional multi-body dynamic model of the vehicle is formulated integrating the hydro-mechanical frame steering and hydro-pneumatic suspension (HPS) systems. The model parameters are obtained from field-measured data acquired for an unsuspended AFSV prototype and a validated scaled HPS model. The HPS is implemented only at the front axle, which supports the driver cabin. The main parameters of the HPS, including the piston area, and flow areas of bleed orifices and check valves, are selected through design sensitivity analyses and optimisation, considering ride vibration, and roll- and yaw-plane stability performance measures. These include the frequency-weighted vertical vibration of the front unit, root-mean-square lateral acceleration during the sustained lateral load transfer ratio period prior to absolute rollover of the rear unit, and yaw-mode oscillation frequency following a lateral perturbation of the vehicle. The results suggested that the implementation of the HPS to the front unit alone could help preserve the directional stability limits compared to the unsuspended prototype vehicle and reduce the ride vibration exposure by nearly 30%. The results of sensitivity analyses revealed that the directional stability performance limits are only slightly affected by the HPS parameters. Further reduction in the ride vibration exposure was attained with the optimal design, irrespective of the payload variations. The vehicle operation at relatively higher speeds, however, would yield greater vibration exposure.     

Subjective absolute discomfort threshold due to idle vibration in passenger vehicles according to sitting posture

Idle vibration, occurring when a vehicle comes to a stop while the engine is on, is known to be a main cause of discomfort for passengers, and the customer effect has been recently growing. The frequency of idle vibration is determined by the engine type. To lower the vibration, various technologies have been applied to optimize the engine mount and vehicle body structure. In addition to the technological developments, research on human response with a consideration of idle vibration is needed to effectively reduce the level of discomfort experienced by passengers. Seats aimed at enhancing static comfort influence the sitting posture of passengers; sitting posture is a factor affecting human body characteristics that response to idle vibration. This study examined the absolute discomfort threshold of idle vibration according to the sitting postures of 13 taxi drivers. The four sitting postures of subjects on a rigid-body seat without a backrest were variables in the determination of absolute discomfort threshold of idle vibration. The absolute discomfort threshold curves obtained in this experiment were less sensitive to frequency changes than the frequency weighting function of ISO 2631-1.     

四川绵阳安昌河人行景观桥的横向振动与动力设计

随着人行桥跨度的不断增大以及对桥梁美学和城市景观的追求,人行桥的基频不断降低,其振动及带来的行走舒适性问题也相继日益突出。结合一梁拱组合体系的人行景观桥,对人行桥人致振动的理论及动力设计方法进行探讨。     

Parameters optimisation of a vehicle suspension system using a particle swarm optimisation algorithm

The purpose of this paper is to determine the lumped suspension parameters that minimise a multi-objective function in a vehicle model under different standard PSD road profiles. This optimisation tries to meet the rms vertical acceleration weighted limits for human sensitivity curves from ISO 2631 [ISO-2631: guide for evaluation of human exposure to whole-body vibration. Europe; 1997] at the driver's seat, the road holding capability and the suspension working space. The vehicle is modelled in the frequency domain using eight degrees of freedom under a random road profile. The particle swarm optimisation and sequential quadratic programming algorithms are used to obtain the suspension optimal parameters in different road profile and vehicle velocity conditions. A sensitivity analysis is performed using the obtained results and, in Class G road profile, the seat damping has the major influence on the minimisation of the multi-objective function. The influence of vehicle parameters in vibration attenuation is analysed and it is concluded that the front suspension stiffness should be less stiff than the rear ones when the driver's seat relative position is located forward the centre of gravity of the car body. Graphs and tables for the behaviour of suspension parameters related to road classes, used algorithms and velocities are presented to illustrate the results. In Class A road profile it was possible to find optimal parameters within the boundaries of the design variables that resulted in acceptable values for the comfort, road holding and suspension working space.     

Discomfort of vertical whole-body shock-type vibration in the frequency range of 0.5 to 16 Hz

Shock-type vibrations are frequently experienced in vehicles excited by impulsive input, such as bumps in the road, and cause discomfort. Current national and international standard weightings were primarily developed for assessing exposure to sinusoidal or random vibrations and not impulsive excitations or shocks. In this experimental study, various shock signals were systematically produced using the response of a one degree-of-freedom vibration model to hanning-windowed half-sine force input. The fundamental frequency of the shock was varied from 0.5 to 16 Hz at a step of 1/3 of an octave. The magnitude estimation method was used for fifteen subjects to compare the discomfort of shocks with various unweighted vibration dose values between 0.35 ms^−1.75 and 2.89 ms^−1.75 at each frequency. The equivalent comfort magnitude of shock showed greater sensitivity at frequencies less than 0.63 Hz and at the resonance frequency of the human body between 5.0 Hz and 6.3 Hz. The frequency weighting constructed by using both the equivalent comfort magnitude and the growth rate of discomfort obtained in this study was compared with the current standard weightings, W_b of BS 6841 and W_k of ISO 2631. The derived weightings for shock were applied to the acceleration of the shocks, and an enhanced correlation was proved between the magnitude estimations and the weighted physical magnitude of shock.     

Nonlinearity in the vertical transmissibility of seating: the role of the human body apparent mass and seat dynamic stiffness

The efficiency of a seat in reducing vibration depends on the characteristics of the vibration, the dynamic characteristics of the seat, and the dynamic characteristics of the person sitting on the seat. However, it is not known whether seat cushions influence the dynamic response of the human body, whether the human body influences the dynamic response of seat cushions, or the relative importance of human body nonlinearity and seat nonlinearity in causing nonlinearity in measures of seat transmissibility. This study was designed to investigate the nonlinearity of the coupled seat and human body systems and to compare the apparent mass of the human body supported on rigid and foam seats. A frequency domain model was used to identify the dynamic parameters of seat foams and investigate their dependence on the subject-sitting weight and hip breadth. With 15 subjects, the force and acceleration at the seat base and acceleration at the subject interface were measured during random vertical vibration excitation (0.25–25 Hz) at each of five vibration magnitudes, (0.25–1.6 ms^?2 r.m.s.) with four seating conditions (rigid flat seat and three foam cushions). The measurements are presented in terms of the subject's apparent mass on the rigid and foam seat surfaces, and the transmissibility and dynamic stiffness of each of the foam cushions. Both the human body and the foams showed nonlinear softening behaviour, which resulted in nonlinear cushion transmissibility. The apparent masses of subjects sitting on the rigid seat and on foam cushions were similar, but with an apparent increase in damping when sitting on the foams. The foam dynamic stiffness showed complex correlations with characteristics of the human body, which differed between foams. The nonlinearities in cushion transmissibilities, expressed in terms of changes in resonance frequencies and moduli, were more dependent on human body nonlinearity than on cushion nonlinearity.     

空气弹簧座椅在冲击式压路机上的应用

针对冲击式压路机牵引主机座椅悬架系统与车的刚性连接问题,提出了应用空气弹簧座椅的设想。应用机械系统动力学软件ADAMS建立了牵引车仿真模型、减振器仿真模型及D级路面时域仿真激励信号,并加入相关约束组成整车振动仿真模型,进行振动仿真分析,结果表明：空气弹簧座椅的整车振动仿真模型可以有效地衰减人体受到的振动。     

对汽车平顺性评价方法的探讨与建议

首先分析了现行国家标准GB4970-1996<汽车平顺性随机输入行驶试验方法>与国际上通行的人体振动评价标准ISO2631-1997的区别.通过道路试验测量了驾驶员坐垫、靠背和脚部的平移振动以及坐垫的旋转振动共lO个方向的振动.分析发现汽车中人体振动的峰值因子一般小于9;而按照GB4970和ISO2631的试验数据对比表明,GB4970在一定程度上低估了人体振动.分析各方向振动所占的比例发现,坐垫垂向振动、靠背前后振动和坐垫侧倾振动影响最大.最后提出了对汽车平顺性评价方法的建议.