Human Biodynamic Responses to Whole-Body Vehicular Vibration and Vibration Control

建议的研究涉及座椅与粘弹性座椅耦合时，座椅人体对矢状面全身振动(WBV)的反应的特征和建模，以及通过控制振动来防止潜在的振动伤害。用于资源、建筑和工业部门的越野车辆具有复杂的平顺性振动和有限的方向稳定性。流行病学研究已经证实，除了降低工作效率外，许多工作车辆的振动强度与司机受伤的报告之间存在很强的相关性。由于对更高载重能力和更高速度的需求不断增加，未来的车辆预计将表现出更严重的WBV和不利的稳定性限制。考虑到人体对振动能量的吸收，生物动力学特性对于设计振动控制系统，即二次悬架和一次悬架，以及对未来以人为中心的工作车辆的设计都是至关重要的。因此，正在继续努力确定生物动力学措施的特征，以得出：(1)用于评估暴露风险的频率加权；(2)用于座椅设计和振动控制装置应用的生物动力学模型；以及(3)用于有效评估座椅的人体动力学人体模型。然而，报道的反应总是在车身与刚性座椅和理想化振动相结合的情况下获得的，这并不能代表车辆的普遍情况。车身与弹性座椅的耦合大大改变了它的机械性能，从而影响了减振。因此，到目前为止，已报道的生物动力学反应和模型的应用取得的成功有限。这主要归因于缺乏与弹性座椅的车身相互作用和足够的测量系统。此外，由于悬架对车辆稳定性的不利影响，通过悬架设计控制乘坐振动不能以孤立的方式进行。因此，主要目标包括：(I)人体与弹性座椅耦合并暴露于垂直和纵向WBV的矢状面生物动力学响应的实验表征和建模；以及(Ii)通过综合平顺性、操纵性和稳定性车辆模型设计创新的悬架。阻性压力传感栅格将用于测量人体-座椅界面力和对WBV的生物动力学响应。在最近的一项研究中建立的测量系统的频率响应将被用于补偿其有限的带宽。由于对身体质量、靠背支撑和座椅弹性的强烈依赖，这项研究将包括身体质量在三个范围内并具有不同座椅弹性特性的受试者。目标生物动力学响应将被定义为身体质量和座椅弹性的函数。对刚性座椅获得的响应将用于校准三个质量的身体的多体生物动力学模型。标定后的模型将与座椅的有限元模型相结合，从而表征与弹性座椅耦合的身体的生物动力学响应。通过对悬架座椅的试验和仿真，将建立模型来可靠地描述典型垂直和前部车辆WBV下座椅乘员响应的可行性。这项研究随后将集中在一次悬架的创新设计上，包括轴间耦合的油气支柱。将开发一个框架转向车辆的综合平顺性和操纵性模型，包括转向支柱的运动动力学、不同布局的液压连接悬架以及相关的轮胎-地形相互作用。

Proposed study concerns characterization and modeling of seated human responses to whole-body vibration (WBV) in the sagittal plane when coupled with visco-elastic seats and prevention of potential vibration injuries through control of vibration. Off-road vehicles employed in the resource, construction and industrial sectors exhibit complex ride vibration and limited directional stability. Epidemiological studies have established strong correlations between magnitudes of vibration of many work vehicles and reported injuries among drivers, in addition to reduced work efficiency. Owing to increasing demand for higher load capacity and speeds, future vehicles are expected to exhibit more severe WBV and adverse stability limits. Considering the absorption of vibration energy by the body, characterization of biodynamics is vital for design of vibration control systems, namely secondary and primary suspensions, and to contribute to human-centered future work vehicles designs. Considerable efforts are thus continuing to characterize biodynamic measures for deriving: (i) frequency-weighting for assessing exposure risks; (ii) biodynamic models for applications in seating design and vibration control devices; and (iii) anthropodynamic manikins for efficient assessments of seats. The reported responses, however, have been invariably obtained with body coupled with rigid seats and idealized vibration, which are not representative of conditions that prevail in vehicles. The body coupling with an elastic seat substantially alters its mechanical properties and thereby affects the vibration absorption. Consequently, applications of reported biodynamic responses and models have met limited success thus far. This is mostly attributed to lack of body interactions with elastic seats and adequate measurement systems. Furthermore, the control of ride vibration through suspension designs cannot be conducted in an isolated manner due to adverse effects of suspension on vehicle stability. The primary objectives thus include: (i) experimental characterization and modeling of sagittal plane biodynamic responses of human body coupled with elastic seats and exposed to vertical and fore-aftl WBV; and (ii) designs of innovative suspensions through integrated ride, handling and stability vehicle models. The resistive pressure sensing grids will be used to measure body-seat interface forces and biodynamic responses to WBV. The frequency response of the measurement system, established in a recent study, will be applied to compensate for its limited bandwidth. Owing to strong dependence on body mass, back support and seat elasticity, the study will include subjects with body mass within three ranges and varying seat elastic property. The target biodynamic responses will be defined as functions of body mass and seat elasticity. The responses, obtained for a rigid seat, will be used to calibrate multi-body biodynamic models of the body of three masses. The calibrated models will be integrated with a finite element model of the seat so as to characterize the biodynamic responses of the body coupled with elastic seat. The feasibility of the models to reliably represent the seat-occupant response under typical vertical and fore-aft vehicle WBV will be established through experiments and simulations with suspension seats. The study will subsequently focus on innovative designs in primary suspensions involving inter-axle coupled hydro-pneumatic struts. An integrated ride and handling model of a frame-steer vehicle will be developed incorporating kineto-dynamics of the steering struts, different layouts of hydra-connected suspension and correlated tire-terrain interactions.