The Temperature Field Study Of Electric Load On Repair Area Of Carbon Fiber Composite

In this paper, the electric-thermal damages process of single lap joint model and CFRP after repair was studied by FEM(Finite Element Method) and experiment.FEM model was established to calculate temperature field and its change rules after CFRP laminated plates was subjected to the direct current by commercial FEM software ABAQUS base on the theory of coupled thermal-electric field. The surface temperature field of specimens electrified was measured by the self-devised damage test device and fine consistency was reached by contrast of the experimental and simulant results. In order to study the effect of electric load on the structure performance of composite after repair, the tensile shear strength test and residual compression strength after impact was tested. The results of simulation and test are as follows:(1)The resistance of the lap joint specimen is a linear relationship with current strength in the process of the electricity. The temperature of joint surface rise with the increase of current intensity. The current density per unit area between layers is reduced with the increase of lap length. After the completion of the load current, the interlaminar shear property of lap joint is researched. It is demonstrated that shear strength slight increase under low electric currents since the post curing of resin. The higher current application has a detrimental effect on the properties of the joint. The hear strength decrease under higher electric currents since the high temperature can induce interfacial damage of joint.(2)The resistance of the lap joint specimen is a linear relationship with current in the process of the electricity too. The temperature of laminate surface increased with the increase of current intensity. Because of the heat exchange system, laminate core temperature significantly is higher than the surrounding area. The discontinuity fiber structure is caused by laminate damage. It affect the current transport mechanism directly so that the patch temperature is lower. The temperature difference is less than2℃. The residual compression strength of laminate is researched after electrify.Preliminary results revealed that low current do not cause structural damage to laminate after repair. It has no effect on the impact performance. The residual compression strength is improved with the post curing of resin. The high temperature destroyed adhesive property of the interface layer with the increase of current intensity. The impact performance and residual compression strength decrease obviously.