弧长法跟踪自锁折叠网架折叠全过程

APPLICATION OF ARC-LENGTH METHOD TO TRACING FOLDING PROCESS OF SELF-HOLD FOLDABLE STRUCTURES

分析了自锁折叠结构构成、几何设计参数和结构自锁原理。自锁折叠结构利用其在折展过程中的越跃特点实现自锁。针对这一折展过程中存在的几何非线性问题,采用弧长法进行了全过程跟踪。分析介绍了弧长法原理及其两个重要参数——荷载增量因子和增量弧长的选取方法。通过对自锁式四棱柱折叠单体折叠过程的荷载位移路径应用弧长控制算法,实现了从前屈曲状态到后屈曲路径的自然过渡,说明弧长算法在越跃问题上的有效性。

As one kind of deployable structures, foldable structures are a new type of space structure used in civil engineering. The constitution and geometric design parameters are discussed and self-locking theory of foldable structures is investigated. Using the snap-through phenomenon in the process of deployment, foldable structures can be self-locked. On account of the geometrically nonlinear problems in the process of deployment of self-locking foldable structures, the Arc-length method and the choices of its parameters, load incremental modulus and Arc-length increment are developed. With the Arc-length method the load-displacement path in folding process of self-locking square prism units have been conducted. It can be accomplished suecessfully to transit form the pre-bucking state to the post-bucking path.