Authors have assumed that the geometrical model of a compressed and a core cylinder will represent creases of a sleeve and an arm, and investigated the change of the form of the creases generated by compressing the cylinder.
While a Yoshimura' s pattern composed of isosceles triangles has been adopted as a model of the creases, authors have cut top and bottom parts of elemental triangles and made generalized the Yoshimura' s pattern composed of trapezoids. Since authors could not decide the form of generalized Yoshimura' s pattern geometrically, authors introduced elastic energy and assumed that the form with the lowest energy was liable to be generated.
In conclusion, the Yoshimura' s pattern was generated when the ratio of compression was less than 15%. The larger the ratio of the radius of the core became, the easier the generalized Yoshimura' s pattern was generated. The change of the form of the creases generated by compressing the cylinder was divided into four steps. In the first step, the Yoshimura' s pattern was generated. The space became narrower gradually and the number of nodes decreased rapidly. In the second step, the Yoshimura' s pattern was also generated. However, in this case, the compressed cylinder and the core cylinder came into contact with each other and the number of nodes remained unchanged. In the third step, the generalized Yoshimura' s pattern was generated for the first time. Two cylinders came into contact with each other and the number of nodes decreased a little. In the fourth step, the generalized Yoshimura' s pattern was generated, and two cylinders came into contact with each other. The number of nodes changed little.

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