Wang Yang, Rahmatalla Salam
Department of Civil and Environmental Engineering, College of Engineering, The University of Iowa, Iowa City, IA 52242, USA.
J Biomech Eng. 2013 Jun;135(6):61010-13. doi: 10.1115/1.4024164.
The development of predictive computer human models in whole-body vibration has shown some success in predicting simple types of motion, mostly for seated positions and in the uniaxial vertical direction. The literature revealed only a handful of papers that tackled supine human modeling in response to vertical vibration. The objective of this work is to develop a predictive, multibody, three-dimensional human model to simulate the supine human and underlying transport system in response to multidirectional whole-body vibration. A three-dimensional dynamic model of a supine human and its underlying transport system is presented in this work to predict supine-human biodynamic response under three-dimensional input random whole-body vibration. The proposed supine-human model consists of three interconnected segments representing the head, torso-arms, and pelvis-legs. The segments are connected via rotational and translational joints that have spring-damper components simulating the three-dimensional muscles and tissuelike connecting elements in the three x, y, and z directions. Two types of transport systems are considered in this work, a rigid support and a long spinal board attached to a standard military litter. The contact surfaces between the supine human and the underlying transport system are modeled using spring-damper components. Eight healthy supine human subjects were tested under combined-axis vibration files with a magnitude of 0.5 m/s2 (rms) and a frequency content of 0.5-16 Hz. The data from seven subjects were used in parameter identification for the dynamic model using optimization schemes in the frequency domain that minimize the differences between the magnitude and phase of the predicted and experimental transmissibility. The predicted accelerations in the time and frequency domains were comparable to those gathered from experiments under different anthropometric, input vibration, and transport conditions under investigation. Based on the results, the proposed dynamic model has the potential to be used to provide motion data to drive a detailed finite element model of a supine human for further investigation of muscle forces and joint dynamics. The predicted kinematics of the supine human and transport system would also benefit patient safety planners and vibration suppression designers in their endeavors.
预测性计算机人体模型在全身振动方面的发展已在预测简单运动类型上取得了一些成功，主要针对坐姿且在单轴垂直方向。文献表明，仅有少数几篇论文涉及仰卧位人体对垂直振动的建模。本研究的目的是开发一个预测性的多体三维人体模型，以模拟仰卧位人体及基础运输系统对多向全身振动的响应。本文提出了一个仰卧位人体及其基础运输系统的三维动态模型，用于预测在三维输入随机全身振动下仰卧位人体的生物动力学响应。所提出的仰卧位人体模型由三个相互连接的部分组成，分别代表头部、躯干 - 手臂和骨盆 - 腿部。这些部分通过具有弹簧 - 阻尼组件的旋转和平移关节相连，这些组件在三个x、y和z方向上模拟三维肌肉和类似组织的连接元件。本研究考虑了两种类型的运输系统，一种是刚性支撑，另一种是连接到标准军用担架的长脊柱板。仰卧位人体与基础运输系统之间的接触面使用弹簧 - 阻尼组件进行建模。八名健康的仰卧位人体受试者在合成轴振动文件下进行了测试，振动幅值为0.5 m/s²（均方根），频率范围为0.5 - 16 Hz。使用频域中的优化方案，将七名受试者的数据用于动态模型的参数识别，以最小化预测和实验传递率在幅值和相位上的差异。在不同的人体测量、输入振动和所研究的运输条件下，预测的时域和频域加速度与实验采集的加速度相当。基于这些结果，所提出的动态模型有潜力用于提供运动数据，以驱动仰卧位人体的详细有限元模型，进一步研究肌肉力量和关节动力学。仰卧位人体和运输系统的预测运动学也将有助于患者安全规划者和振动抑制设计师的工作。
