中文摘要：

采用乙烯-四氟乙烯共聚物（ETFE）薄膜哑铃形试件,进行单轴拉伸试验,得到了工程中常用的ETFE薄膜的力学参数（屈服强度、屈服应变、切线模量和割线模量）;在考虑ETFE薄膜粘弹塑性效应特征的前提下,应用应变能等效的方法计算ETFE薄膜等效弹性模量,结果表明计算得到的等效弹性模量介于切线模量和割线弹性模量之间.研制了一种专用于ETFE薄膜双轴拉伸试验的装置,并进行了系列试验;基于正交异性薄膜理论推导出薄膜双向解耦的独立弹性常数计算列式.根据ETFE薄膜双轴拉伸应力-应变曲线,求得厚度为250μm的ETFE薄膜在双边应力比为1：1的工况下的耦合模量为1163 MPa;由正交异性理论计算得该薄膜的解耦模量为814.2 MPa,与单轴拉伸试验得到的等效弹性模量相近.

英文摘要：

In the investigation, a dumbbell-shape ETFE foil specimen is employed to conduct mono-uniaxial tensile tests, thus obtaining commonly-used mechanical parameters, namely, yield strength, yield strain, tangent modulus and secant modulus. According to the visco-elastic and plastic features of ETFE foils, the equivalent strain energy me-thod is adopted to calculate the equivalent elastic modulus of ETFE foils. It is found that the calculated equiva- lent elastic modulus falls in between the tangent modulus and the secant elastic modulus. Then, a set-up is devel- oped particularly for the biaxial test of ETFE foils and is used to perform a series of corresponding tests, and the de- coupled biaxial elastic modulus is formulated according to the orthotropic elastic film engineering theory. Based on the stress-strain curve of the biaxial tensile test of ETFE foils, the coupled modulus of a 250μm ETFE foil is found to be 1 163 MPa at the bilateral stress ratio of 1： 1. Based on the orthotropic theory, the decoupled modulus of the ETFE foil is found to be 814.2 MPa, which is close to the equivalent elastic modulus obtained through the uniaxial tensile test.