Modeling of Human-Spine System and Production of Vibration Dummy for the Evaluation of Vibration Effect

振动对人体脊柱的影响是从健康角度考虑的。职业司机在驾驶工程机械和卡车时，会受到全身振动的影响。ISO 2631 -1或ISO 2631 -5中规定了振动暴露的指导原则。这是强烈要求审查这些指南的有效性，以保护职业司机的振动障碍。为了了解人体的振动特性，并从健康的角度评价振动对脊柱的影响，本研究进行了振动实验，以了解坐姿人体的基本振动特性。重点研究了脊柱的振动特性，在0- 20 Hz的频率范围内识别出三个基本模态。一个多体模型的构建，它描述了实验检测到的模态特性。椎骨被建模为刚体，椎间盘被建模为旋转弹簧和旋转阻尼器。该模型具有11个自由度，并用于研究振动假人的结构，建立了脊柱评价用振动假人。椎骨是根据解剖骨骼标本制成的，椎间盘是由硅胶材料制成的。结果表明，脊柱后部的韧带和肌肉以及腹内压对脊柱的稳定起着重要的作用。这些元素也被添加到振动假人中。假人的重量达到30公斤，仍然比标准的人体上半身轻，后者重约50公斤。然而，假人代表了振动实验检测到的基本动态特性。总结了振动假人实现动态特性的基本原理。

The vibration effect on human spinal column is concerned from the viewpoint of health. The occupational drivers are exposed to the whole-body vibration when driving the construction machines and the trucks. The guideline of vibration exposure is stipulated in ISO2631-1 or ISO2631-5. It is strongly demanded to examine the validity of those guidelines for protecting the occupational drivers from vibration disorders. The goal of this study is to understand the vibration properties of human body and to evaluate the vibration effect to the spinal column from the viewpoint of health.The vibration experiment is conducted in order to understand the fundamental vibration characteristics of seated human body. The behavior of spinal column is specially focused on, and three fundamental modes are identified in the range of 0-20Hz. A multi-body model is constructed which describes the experimentally detected modal properties. The vertebrae are modeled as rigid bodies, and the intervertebral discs are as rotational springs and rotational dampers. The model has as much as 11 degree-of-freedoms, and is utilized to investigate the structure of vibration dummy.The vibration dummy for evaluation of spinal column is built. The vertebrae are made based on the anatomical skeletal specimen, and the intervertebral discs are made from silicone material. It is revealed that the ligaments and the muscles in the back of the spinal column and the IAP (Intra-Abdominal Pressure) play an important role to stand the spinal column in stable. Those elements are also added to the vibration dummy. The mass of the dummy goes up to 30kg, which is still lighter than the standard human upper body, which weighs about 50kg. However, the dummy represents the fundamental dynamic properties detected by the vibration experiment. The fundamental principles to realize the dynamic properties by the vibration dummy are summarized.