Study On Basic Mechanical Properties Of Ti/APC-2Fiber Metal Laminates By Finite Element Method

Fiber metal laminates are a kind of new super hybrid composites with excellent mechanicalproperties. Ti/APC-2fiber metal laminates in this thesis are moulded by titanium alloys(TA2) andAPC-2prepregs. They have a number of desirable features including high strength to weight ratio,nice environmental and fatigue resistibility, good damage tolerance, withstand lightning performance,good machinability and damping characteristics.In this paper, the research is mainly on basic mechanical properties of Ti/APC-2compositelaminates by the finite method. The main content of the thesis includes3aspects as follows:First, based on classical laminated theory, the residual stress of the2/1structure of carbonfiber-titanium hybrid composite laminates was calculated by analytical method and finite elementmethod. Stress-releasing method was adopted to test the residual stress. The calculated results agreedwell with the experimental result. The effect of pre-stress loading on the residual stress was alsodiscussed with analytical method and finite method. The research work in this paper will providevaluable theory reference to design and develop the laminates with the best performances.Second, Fracture Behavior Analysis of Ti-PEEK was evaluated by the combination of aexperimental method of double-cantilever-beam(DCB) and the finite element method. The criticalloads PC and energy release rates were obtained through DCB experiment. For the Purpose of gettingstress-strain field, these tests were combined with finite element analysis. The complex stress intensityfactor was computed using the definition of definition of complex stress intensity factor. The researchfound the K-dominant zone existed near the crack tip. The energy release rates and stress intensityfactors of Ti-PEEK with untreated titanium alloys and sandblasted titanium alloys. The results ofcalculation under two kinds of situations are compared, the influence of surface treatment of titaniumalloys on Ti-PEEK adhesive strength was preliminarily explored.Last, The research methodology applied in the present thesis is numeric calculation. On the basisof Nonlinear Dynamic Analysis Software ANSYS/LS-DYNA, established the macro-response modelof fiber composite, simulated the damage and failure process of fiber metal laminates under the lowimpact. The critical speed was obtained， moreover， the residual velocity of drop-weight and thedeformation and stress of fiber metal laminates were analyzed. Then compare the numerical valuewith the experimental result in drop-weight experiment. The main research contents are as follows：（1）The constitutive relations and failure criterions of titanium alloy and fiber composite were systematically analyzed.(2) The drop-weight impacts on the titanium alloy and fiber composite wereseparately simulated and the process of drop-weight impact was detailedly analyzed.(3) Thedrop-weight impact on the Ti/APC-2fiber metal laminates was finally simulated, Ti-PEEK adhesivestrength was also considered，analyzed the damage and failure of Ti/APC-2fiber metal laminates andevaluated the impact resistance.(4)Compared to the experimental results, the reasonability andcorrectness of simulated results were improved.