International Journal of Damage Mechanics

Stress corrosion cracking is an important and complex mode of failure in high-performance structural metals operating in deleterious environments, due to metallurgical, mechanical, and electrochemical factors. Depending on the material/solution system, the stress corrosion cracking mechanism may involve a combination of hydrogen embrittlement (HE) and anodic dissolution. In this article, a numerical model for predicting the mechanical behavior of hydrogen-induced damage in stress corrosion cracking is described. The methodology of modeling used in this study is based on the thermodynamics of continuum solids and elastoplastic damage. This model is based on a stress corrosion mechanism that occurs through the simultaneous interaction of hydrogen and plasticity. This mechanism is also called hydrogen-enhanced localized plasticity, which is a viable mechanism for hydrogen embrittlement. The model is applied to the fatigue damage problems of nuclear reactor pipe, and the results are compared with published fatigue life data obtained experimentally.

FEM results of softening materials are well known to show pathological mesh dependency. The main goal of this work is to revisit and propose efficient nonlocal damage gradient enhanced formulations able to avoid mesh dependency in the context of elastoplastic damage models with destination to industrial applications. This formulation is presented and studied for simple tension tests, with various spatial discretizations. Numerical aspects and implementation in ABAQUS-standard environment are discussed. The structure of the nonlocal element needed for those formulations is presented. For a given set of meshes, the ability of the proposed formulation to control the size of the necking zone is studied. In the same time the independence of the global dissipation to the mesh size is checked. Theoretical and practical limits of the proposed approach are highlighted.

In this study, based on the Miner rule, a new linear damage accumulation rule is proposed to consider the strengthening and damaging of low amplitude loads with different sequences using fuzzy sets theory. This model improves the application of the traditional Miner rule, by considering not only the damaging and strengthening of low amplitude loads, but also the load sequence effects. To apply the proposed model, the law of selecting membership functions for different load spectra is found, and different membership functions are investigated to show the important influence on estimating fatigue life. Applicability of the method is validated by comparing with the experimental data. It is also found that the predicted fatigue life by the proposed method is more accurate and reliable than that by the traditional ones.

This article illuminates some general features and provides elementary interpretations of the deformation, damage, and failure of brittle solids characterized by very low fracture energy. The dynamic response of these materials is determined to a large extent by stochastic and random factors. The investigation emphasis is on the moderate-to-extremely high rate range (10 s^-1, 1 × 10⁹ s^-1), explored under practically identical in-plane stress conditions. The statistical approach is based on repeated particle dynamics simulations for different physical realizations of micromechanical disorder of a 2D brittle discrete system. The proposed strategy is computationally intensive, which necessitates simplicity of the laws governing the interparticular interaction. Based on the simulation results, an expression is proposed to model the mean tensile strength dependence on the strain rate. The linearity of the rate dependence of the stress-peak macroscopic response parameters is observed and discussed.

A progressive micromechanical damage-plasticity formulation is proposed to analyze the single hooked-end steel fiber pullout energy from the surrounding cement-based matrix within the context of hooked-end steel fiber-reinforced cementitious composites (HSFRCC). As the hooked-end steel fiber has a unique fiber geometry, its fiber pullout energy from the cement-based matrix consists of the interfacial fiber-matrix debonding, the frictional sliding and pullout energy, and the elastoplastic deformation energy of the steel fiber hooked end. The aforementioned energy components are analytically derived first, and the superposition principle is subsequently employed to obtain the total energy dissipation during the fiber pullout process. Good agreement is obtained for comparisons between the experimental results of single hooked-end steel fiber pullout tests and the proposed analytical predictions. This satisfactory verification supports the validity and applicability of the proposed damage-plasticity energy prediction formulation, and suggests the applicability of this methodology to further investigation on micromechanical fracture energy prediction of HSFRCC during flexural macro-cracking.

The aim of this article is to propose a macroscopic damage model, which describes the nonlinear behavior observed on woven composites with ceramic matrix. The model is built within a thermodynamic framework with internal variables. First of all, the efficiency of the model to describe the mechanical behavior of carbon fiber-reinforced ceramic matrix composites is outlined. Then, the predictive capability of the model is evaluated with the help of an alternate torsion test.