Nakatani of Osaka University has come out with the statement that the multi-scale analysis of the dynamic behavior of materials can be carried out if techniques of molecular dynamics and dynamic techniques of continuum are combined. According to Nakatani, molecular dynamics is beginning to be used for the analysis of materials. Materials are analyzed by a method described below. In regard to the relationship between the scale and characteristics of test pieces, consideration will now be given to the pulling of 1-dimensional models of atoms connected with non-linear springs, as illustrated in Fig. 1. Two models having different numbers of springs, 5-chain model (Fig.1(a)) and 3-chain model (Fig.l(b)) are examined here. The state (II) is obtained if about 50% uniform pulling strain is applied to the natural state (I). When consideration is given to the interatomic potential (here the interaction of the nearest atoms is not taken into consideration for simplicity's sake), as shown in Fig.1(c), then there is a limit to how much pulling force can be applied because of the non linearity of the springs. If too much pulling force is used, the spring connections are severed and destroyed.
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