ABSTRACT

Flexible and foldable electronic products often contain adhesive layers, and failure generally initiates at the adhesive interfaces. To analyze the interfacial stress accurately, correct constitutive relationship of adhesive layers is necessary. However, soft adhesives used in foldable sandwich plates can show rate-dependent and anisotropic mechanical behaviors, which can hardly be implemented by traditional linear elastic and hyperelastic constitutive models in the folding process simulation. Through experiments in material’s principal axes and the strain energy equivalence principle, a transversely isotropic and rate-dependent constitutive relationship of adhesive has been developed in a three-dimensional form. By commercial finite element (FE) software ABAQUS and its user subroutine UMAT, the folding stress of a sandwich plate has been analyzed. The results of FE simulation show that folding time would affect stress distributions significantly due to the anisotropic and rate-dependent properties of adhesive.

摘要

柔性和可折叠的电子产品通常包含粘合剂层，并且失效通常始于粘合剂界面。为了准确分析界面应力，需要正确的胶层本构关系。然而，可折叠夹芯板中使用的软粘合剂会表现出与速率相关和各向异性的力学行为，这是传统的线弹性和超弹性本构模型在折叠过程模拟中难以实现的。通过对材料主轴和应变能等效原理的实验，以三维形式发展了粘合剂的横向各向同性和速率相关的本构关系。通过商业有限元（FE）软件ABAQUS及其用户子程序UMAT，对夹层板的折叠应力进行了分析。