各向同性体积膨胀导致的双层条结构大挠度弯曲

Large deflection of a bilayer soft strip due to incompatibility of isotropic volumic expansion

传统双层材料的弯曲理论主要针对小变形、线弹性材料.这里我们研究了双层条的大变形弯曲,建立了一个描述双层条大变形弯曲的理论.理论中假设双层条由一个主动层和一个被动层组成,只有主动层会产生各向同性体积膨胀.分析表明我们的理论预测与有限元模拟符合较好,而在某些情况下会与传统理论预测有明显的差异.我们理论分析还表明,存在能使双层条得到最大曲率的最佳模量比及厚度比.我们的理论可促进软质双层条带材的设计,可广泛用于多个领域.

Since the traditional bending theory of bilayers was mainly for linear elastic materials with the assumption of infinitesimal deformation,here we study the bending of a bilayer soft strip with large deformation.The strip under investigation is comprised of an active layer and a passive layer,where only the active layer is assumed to be subjected to an isotropic volumic expansion.A bending theory for the large deformation of the strip is then developed.The subsequent analysis indicates that our theoretical predictions agree well with the finite element simulation,which,however,can significantly diverge from those predicted by the traditional theory under certain circumstances.With our theory,it is also shown that there exists an optimal modulus ratio or thickness ratio for a bilayer strip to achieve a maximal curvature.We suggest that our theory may greatly facilitate the design of soft bilayer strips that can be potentially employed in varied fields.