Gupta Manoj, Gupta T C
Department of Mechanical Engineering, Malaviya National Institute of Technology, Jaipur 302017, India e-mail: .
J Biomech Eng. 2017 Oct 1;139(10). doi: 10.1115/1.4037403.
The present study aims to accurately estimate inertial, physical, and dynamic parameters of human body vibratory model consistent with physical structure of the human body that also replicates its dynamic response. A 13 degree-of-freedom (DOF) lumped parameter model for standing person subjected to support excitation is established. Model parameters are determined from anthropometric measurements, uniform mass density, elastic modulus of individual body segments, and modal damping ratios. Elastic moduli of ellipsoidal body segments are initially estimated by comparing stiffness of spring elements, calculated from a detailed scheme, and values available in literature for same. These values are further optimized by minimizing difference between theoretically calculated platform-to-head transmissibility ratio (TR) and experimental measurements. Modal damping ratios are estimated from experimental transmissibility response using two dominant peaks in the frequency range of 0-25 Hz. From comparison between dynamic response determined form modal analysis and experimental results, a set of elastic moduli for different segments of human body and a novel scheme to determine modal damping ratios from TR plots, are established. Acceptable match between transmissibility values calculated from the vibratory model and experimental measurements for 50th percentile U.S. male, except at very low frequencies, establishes the human body model developed. Also, reasonable agreement obtained between theoretical response curve and experimental response envelop for average Indian male, affirms the technique used for constructing vibratory model of a standing person. Present work attempts to develop effective technique for constructing subject specific damped vibratory model based on its physical measurements.
本研究旨在准确估计与人体物理结构一致且能复制其动态响应的人体振动模型的惯性、物理和动态参数。建立了一个用于站立人体在支撑激励下的13自由度（DOF）集总参数模型。模型参数由人体测量数据、均匀质量密度、各个身体节段的弹性模量和模态阻尼比确定。通过比较从详细方案计算出的弹簧元件刚度与文献中相同的可用值，初步估计椭球体节段的弹性模量。通过最小化理论计算的平台到头部传递率（TR）与实验测量值之间的差异，进一步优化这些值。使用0-25Hz频率范围内的两个主峰，从实验传递率响应中估计模态阻尼比。通过模态分析确定的动态响应与实验结果之间的比较，建立了一组人体不同节段的弹性模量以及一种从TR图确定模态阻尼比的新方案。除了在非常低的频率下，从振动模型计算出的传递率值与第50百分位美国男性的实验测量值之间的匹配可接受，证实了所开发的人体模型。此外，平均印度男性的理论响应曲线与实验响应包络之间获得了合理的一致性，肯定了用于构建站立人体振动模型的技术。目前的工作试图基于其物理测量开发一种有效的技术来构建特定受试者的阻尼振动模型。
