IJBSCHS(2014-0x-xx-xx) Biomedical Soft Computing and Human Sciences, Vol.x,No.x,pp.000-000) [Original article] Copyright©1995 Biomedical Fuzzy Systems Association (Accepted on 2014.xx.xx) 1 Microscopic Simulations of Shock Wave Propagation in Pseudo-skull Masahiro Nakano 1,6 , Hiroyuki Matsuura 2,6 , Masaaki Tamagawa 3,6 , Toru Yukimasa 4,6 , Makoto Yamanaka 1,6 , Masami Kubota 5,6 㧝 Junshin Gakuen University 2 National Center for Geriatrics and Gerontology 3 Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology 4 University of Occupational and Environmental Health 5 Japan Automobile Research Institute (JARI) 6 New Energy and Industrial Technology Development Organization (NEDO) Abstract: This paper develops a basic numerical scheme for a pseudo-skull matter and shows how to construct a reliable model. First, we solve one dimensional model and shows the solutions, which we cannot expect before numerical calculation. Next we solve two dimensional model and compare the results of one and two dimensional models. From the comparison, we understand the important feature of the propagation of shock wave, i.e., the shock wave goes to directly on a line without spreading into the other dimension in the matter. This means the one dimensional model is useful, since it can give an essential feature of the shock wave. Finally, we show the energy and momen- tum conservation low holds while the calculation. Keywords fall accidents , pseudo-skull, shock wave, solution of one and two dimensional mod- els, position, velocity, dummy robot, oscillation. 1.Introduction Dead from fall accidents is a severe problem in Ja- pan, especially for senior people. Fall accidents cause often head injury, which is determined by the impulse force and acceleration, and many researches are intended to clarify the relation the force and human injury [1]-[3]. However, the detailed relation between injury and the impulse is quite indefinite because the experiment using human cannot be performed. Therefore, the experiment using a dummy robot similar to human body is conducted, and the result has been analyzed [4] -[7]. The accel- erometers have been set to measure in four parts of the body, head, chest, pelvis and neck. These acceleration data is one of the basic data to obtain the relation be- tween the grade of a head shock and cerebral external injury. On the basis of the data, we have deduced the Masahiro NAKANO Junshin Gakuen University, Fukuoka, Japan Phone: +81-92-554-1255, Fax: +81-92-553-5484 E-mail: nakano.m@junshin-u.ac.jp deformation of the head. However, we should check that the deformation is correct and how the micro defor- mation propagates in the skull. In order to investigate this problem, we analyze a uniform matter. The main subject is to analyze theoretically how micro deformation occurs and propagates in the matter. At first, we adopt a one dimensional model. This model includes essential fea- tures which are commonly observed in an actual impulse. Next, we solve a two dimensional model. Comparing the results with the one dimension results, we understand the common features and the specialty of the one dimension- al model. These results include new knowledge on the shock wave propagation in a pseudo-skull matter. 2. One dimensional model A simple model is considered in one dimension for a step of developing a calculation frame of the propagation of microscopic shock waves. Then we take one dimen- sional zone, a part of bone, and idealize to discretize in a simple rectangular shapes. ｲｳ IJBSCHS ［Original Article］ Biomedical Soft Computing and Human Sciences, Vol.19, No.1, pp.23-31 CopyrightⒸ1995 Biomedical Fuzzy Systems Association (Accepted on 2014.2.20)