Peridynamic Modeling of Corrosion Fatigue in Metallic Materials
Fatigue failure is the most common form of failure in engineering.Under the interaction be-tweenthe corrosive environment and fatigue load,the fatigue life of a structure is significantly reduced.It often consumes a lot of time and economic costs to evaluate the fatigue properties of materials or structures through corrosion fatigue experiments.Therefore,it is crucial to establish a reliable numerical prediction model for scientific research and engineering design.In this study,we develop a peridynamic corrosion fa-tigue model,which combines the peridynamic fatigue crack model and the peridynamic stress-corrosion model,according to the superposition model of corrosion fatigue.In this model,corrosion fatigue damage is a linear superposition of corrosion damage and fatigue damage,and the coupling between stress and cor-rosion is considered.Consequently,the effect of structural deformation on the corrosion rate,the hetero-geneity of the products,and the geometry of the corrosion front can be considered simultaneously in the model.The new model is then applied to simulate the corrosion fatigue failure process(including crack ini-tiation and crack growth phases)of stainless steel compact tensile specimens.The simulation results show that the model can accurately describe the complete corrosion fatigue failure process of the compact tensile specimen,with the corrosion fatigue crack initiating randomly but consistently around the expected high-stress region.The decrease in fatigue life due to the interaction between the corrosion environment and fa-tigue load is captured,and prolonged corrosion time exacerbates the reduction in fatigue life when a lower load is applied.The influence of loading frequency on corrosion fatigue behavior is investigated by calculat-ing the crack initiation life and comparing crack length curves.The model can also capture the significant influence of loading frequency on the fatigue life in corrosion fatigue processes.Reducing the loading fre-quency extends the corrosion time between each cyclic load,intensifying corrosion damage and ultimately reducing the crack initiation life while accelerating crack growth.The numerical results demonstrate that the introduced mechano-chemical damage model can capture the loading frequency sensitivity.
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