基于初始应变变化的自组装螺旋变形有限元分析

Finite element simulations on mechanical self-assembly of helical shapes driven by initial strains

螺旋结构是自然界和工程应用中的基本形态,在不同几何和力学条件下可实现多种形态间的相互转变。本文以双层薄弹性材料结构模型为例(长度L>>宽度W>>厚度H),利用层间存在的不同初始应变,采用三维有限元模拟方法,分析了结构的形态转变情况。结果表明:当加载单层预应变(ε1=0.25)时,改变几何主轴和初始应变主轴方向间的错配角φ,可实现弹性带在圆环、螺旋形、不完整柱形间相互转变;当加载双层预应变(ε1=-ε2=0.25)时,同时改变几何错配角,可实现弹性带在"轮毂"形、纯扭转、一般扭转间的自组装螺旋相互转变。

Helices are one of the most basic building blocks in natural and synthetic systems. The shape changes can occur under the conditions of different geometric and mechanical changes. In this work, through full three-dimensional finite-element simulations, we applied pre-strains in both the case of one and two of the composite layers with the different geometric mis-orientation between the principal axes of prestrains and the geometric axes. Thus, we can predict the different formation with different mis-orientation., such as ring, pure rotation and cylindrical surface.