Based on the continuous damage mechanics (CDM) theory, Ambartsumyan bimodulus theory and creep damage theory, a bimodulus creep damage constitutive model is proposed in this paper. The model is able to describe the damage-induced unilateral behaviour related to the microdefect closure effect. The unilateral behaviour is considered a special bimodulus property. By judging the tension or compression state in bimodulus theory, different elasticity properties matrixes are selected according to signs of principal stresses. Then, an elasticity properties matrix is linearly converted to a general stress space. The model effectively solves the difficulty of determining tension or compression in complex stress states when the unilateral effect of damage is considered in the analysis of actual structures. The tangent elasticity matrix is used to improve the convergence of the proposed algorithm. In this study, a numerical simulation of the proposed model is achieved by writing subroutines in the FORTRAN language. A numerical example of a hole-in-plate structure under uniaxial stress is analysed. By comparing the results with those obtained by the traditional model, which does not consider the unilateral effect of damage, it is demonstrated that the proposed model is capable of describing the damage-induced unilateral behaviour related to microcracked closure effects. The numerical example validates the effectiveness and realizability of the proposed model.

本文基于连续损伤力学(CDM)理论、Ambartsumyan双模理论和蠕变损伤理论，提出了一种双模蠕变损伤本构模型。该模型能够描述与微缺陷闭合效应相关的损伤引起的单边行为。单边行为被认为是一种特殊的双模特性。通过判断双模量理论中的拉伸或压缩状态，根据主应力的符号选择不同的弹性特性矩阵。然后，将弹性属性矩阵线性转换为一般应力空间。该模型有效地解决了在实际结构分析中考虑损伤的单边效应时，复杂应力状态下难以确定拉压的问题。切线弹性矩阵用于提高算法的收敛性。在这项研究中，通过用 FORTRAN 语言编写子程序来实现所提出模型的数值模拟。分析了单轴应力作用下板中孔结构的数值例子。通过将结果与传统模型所获得的结果进行比较，该模型不考虑损伤的单边效应，表明该模型能够描述与微裂纹闭合效应相关的损伤引起的单边行为。数值算例验证了所提出模型的有效性和可实现性。分析了单轴应力作用下板中孔结构的数值例子。通过将结果与传统模型所获得的结果进行比较，该模型不考虑损伤的单边效应，表明该模型能够描述与微裂纹闭合效应相关的损伤引起的单边行为。数值算例验证了所提出模型的有效性和可实现性。分析了单轴应力作用下板中孔结构的数值例子。通过将结果与传统模型所获得的结果进行比较，该模型不考虑损伤的单边效应，表明该模型能够描述与微裂纹闭合效应相关的损伤引起的单边行为。数值算例验证了所提出模型的有效性和可实现性。