Deploying Properties of Para-Cylinder with Side Polygonal Elements and Its Application to Simple Actuator

本文对几个由边三角形构件组成的可折叠圆柱进行了一系列的展开试验，研究了边三角形构件的形状和布置、折痕长度和侧构件的圆周数等几何参数对展开方式、展开速度、内压和最大有效载荷的影响。同时，还对侧梁展开过程中的应变进行了分析。得到的主要结果如下：1.通过实际折叠一张纸，发现三种不同类型的折叠，即水平折叠、螺旋折叠和重复螺旋折叠，都可以制成可折叠的准圆柱体。当对位圆柱体完全折叠时，圆柱体的横截面就变成了各种多边形。考虑桁架杆件而不是圆柱体一侧的折痕，对杆件的应变进行了解析估计。分析结果表明，螺旋折叠的准圆柱体在展开过程中的应变远小于其他两种折叠方式的圆柱体。对于折边圆柱截面上出现的多边形边的个数N，由于桁架杆件的应变较小，N较大的圆柱体为首选。各种折叠式筒体的扩径试验结果与桁架构件应变分析预测结果吻合较好。实验中表现出最大可展开载荷的副圆柱体是螺旋折叠式圆柱体，N=9。在实验范围内，这种可折叠圆柱体可能是简单执行器的最佳选择。

In this study, a series of expanding tests for some foldable para-cylinders which consist of side triangular members were carried out to investigate the influences of the geometrical parameters such as the shape and the arrangement of side triangular members, the length of creases and the circumferential number of the side members on the unfolding manner, the expanding speed, the inside pressure and the maximum payload during perfect unfolding. The strain in the side members during unfolding is also examined analytically. The principal results obtained are as follows:1. By folding a paper actually, it was found that three different types of folding, horizontal folding spiral folding and repeated spiral folding, can make a foldable para-cylinder. When the para-cylinders were perfectly folded, the cross section of the cylinders become various polygons.2. Considering truss members instead of the creases on the side of a cylinder, the strains of members were estimates analytically. The analysis results showed that the strains of para-cylinders with spiral folding during unfolding are much smaller than those of cylinders with other two folding manners. Concerning the number of the polygon side which appears in the cross-section of the para-cylinder folded, N, the cylinder with larger N is preferred because of smaller strain in the truss members.3. The results of expanding experiments for various foldable para-cylinders agreed well with the prediction by the strain analysis of truss members. The para-cylinder which showed the largest deployable payload in the experiments is a cylinder with spiral folding and N = 9. In the range of experiments, this foldable cylinder may be the best choice for a simple actuator.