Finite Element Simulation of Nanoindentation-Scratch

In the previous chapters, nanoindentation experiments and theoretical derivation were carried out to study the factors affecting the work energy of laminated shale when soft and hard minerals mixed under the striated development conditions. Combined with indentation energy analysis, the ratio Ue/Ut of elastic energy to total energy of laminated shale is affected by dimensionless parameters v1 + v2, Y1 + Y2 and E1 + E2 of laminated minerals. When studying the mechanical properties of shale, it is necessary to consider the composition and structure of the lamination comprehensively, such as the characteristics of different lamination Poisson’s ratio, lamination thickness, and different lamination dip angle on the microscale, instead of only considering a single mechanical parameter. In order to further deduce the specific relationship between mechanical parameters in the process of shale indentation and scratch experiment, commercial software ABAQUS is used to analyze and simulate several influential factors in the indentation and scratch experiment. Using finite elements to simulate the scratch characteristics of the material surface, not only can we obtain the stress distribution of the material, but also we can predict the tendency of crack generation and extension of the material under loading [1]. In addition, based on the magnitude analysis and nanoscratch finite element analysis, the plastic parameters such as yield stress, strain hardening index, and interfacial friction coefficient of the material can be combined dimensionlessly and fitted with the required coefficients [2]. Based on the heterogeneous characteristics, a two-dimensional plane model is established under the mixed conditions of soft and hard minerals, and the lamination process of rich laminated shale with different lamination parameters is simulated. The effects of different scratch depth and scratch displacement on stress transfer and failure modes are discussed based on 3D nanoscratch simulation. The curve fluctuation patterns of ITZ interval of continuous indenter measurement are analyzed.