On Extended Layerwise Method Of Multiphysics Fracture Problem For Multilayer Structures

Multilayer structure is a non-uniform material,which has the advantages of continuous changes in material properties alonge the thickness direction,can adapt to the complex environments and material designability,so it is widely used in aerospace,electromechanical,acoustic optics,petrochemical,nuclear energy and biomedical fields.At the same time,multilayer structures is generally serviced in complex multiphysics environments,and their damage is complex three-dimensional cracks with both interface delaminations and transverse cracks.Based on the extended Layerwise method(XLWM),the multi-physics dynamic fracture problems of multilayer structures in typical damage modes are studied in this paper.The main contents include the following three aspects:Firstly,the XLWM is applied into the steady-state thermo-mechanical coupling problem of composite laminates with damage.One-dimensional weak discontinuity function and strong discontinuity function are used to construct the interlaminar interface and delaminations.The extended finite element method is used to simulate in-plane transverse cracks.The temperature field in the thickness direction is solved by using the one-dimensional quasi-static heat conduction equation.In numerical examples,the present model in this paper is verified by using Classical Laminated Plate Theory(CLPT),First-Order Shear Theory(FSDT),Reddy’s Layerwise Theory(LWT)and three-dimensional elastic model.And then,the chemo-(diffusion)mechanical coupling model is introduced into the XLWM to study the quasi-static problem of the chemo-(diffusion)mechanical coupling model.The mixed time integration is developed based on the Newmark integration algorithm and Crank-Nicolson scheme,and it is employed to study the dynamic problem of chemo(diffusion)-mechcanical coupling.The propagation of cracks and interface damage is predicted by the stress intensity factor and Energy Release Rate.By numerical examples,the dynamic distribution of displacement and concentration is studied for the cases with/without damage.The stress intensity factor and energy release rate are used to analyze the crack damage during the dynamic growth of concentration.Finally,the thermo-mechanical-chemical(diffusion)coupling model is introduced into the XLWM to study the dynamic fracture of functionally graded material plates under the three fields coupling loading.Taking into account the effect of temperature on the material parameters themselves and the effect of particle concentration diffusion under high temperature conditions,the effects of damage on the dynamic distribution of displacement,temperature and concentration are studied.