Analysing the potential mechanism of negative crack growth in fracture based on ABAQUS

In the initial stage of the J - R testing using the unloading compliance technique, the crack growth often exhibits abnormally negative values. The negative crack growth phenomenon indicates that the experimental procedures for measuring crack growth are sometimes flawed and may lead to apparent negative crack growth. This report explores the mechanism of negative crack growth using computational models. A finite element model created by Abaqus is used to test different conditions that may lead to negative crack growth in order to verify the mechanism. These simulations are the selection of a suitable set of parameters to build the model based on CT specimen as the prototype to evaluate the impact on this phenomenon in various scenarios. Through this study, several key results are analyzed and deduced. The observed negative crack growth is essentially a negative crack length computed from the energy. Finite element analysis(FEA) demonstrated that changing the load position, sample rotation and material blunting can result in negative crack growth.