FEM Analyses for Wrapping Fold Model of Membrane Retracted by Guided-Pin Mechanisms

Wrapping fold analyses of a membrane retracted by guided-pin mechanisms are performed using a onedimensional model and FEM analyses to investigate the retraction properties for restoring forces, configuration of creases, and plastic deformation in the membrane. In the analyses, a wrapping fold model, which divides the wrapping fold membrane into the folded state and the transient process, is proposed. Analytical procedures for the folded state of the wrapping fold model are constructed considering the mechanical condition of the folded state. At first, we analyze the wrapping fold model by one-dimensional approximation to determine the retraction properties as a function of the contact force. Then, the retraction properties for the layer pitch and for the membrane thickness are examined using FEM analyses. As the results of these analyses, the configuration of the creases and the contact force are obtained for an arbitrary layer pitch. The Mises stress in the crease is evaluated to examine the existence of the plastic deformation. Comparing the results of these analyses, the applicability of the one-dimensional analyses is discussed. The analytical results are evaluated by experimental studies, and these results are in agreement qualitatively.