Impact Analysis On The Mechanical And Electric Properties Of Composite Structures By Lightning

Composite material is used on the civil aircraft to improve the overall performance and reduce the airline’s operating costs. Due to the low conductivity of the composite material, it cannot shunt the high-current shunt fast during the lightning,so that formed high-temperature of the resistance’s heat ablates the material seriously.At the same time high thermal stress generated by high temperature will also produce material damage. Lightning damage will have an impact on the strength of the material. Lightning electric heating effect and thermal stress are simulated to study.Residual strength of composites is analyzed after damage. The work is used to provide reference for the lightning protection maintenance. The main contents are as follows:(1)Lightning electric heating effect on composites is simulated by ABAQUS.Analysis obtain that the distribution of temperature field is controlled by the direction of layers, but also by the effects of heat conduction of adjacent layers. The high temperature damage is mainly caused in the early lightning due to lightning electricity mainly in the early lightning.(2) The impact of the lightning current and material properties on the damage is analyzed by simulation. The results show that the lightning damage is directly related to the lightning current. The larger of the lightning current peak, the front time of waveform t1 and the time at the half of the current peak after wave t2, the greater damage is caused. The larger of the conductivity of the material,the more favorable to spread damage in the layers, the small of damage depth. Thermal conductivity,specific heat and laminated board size have little effect on the lightning damage.(3) Thermal stress generated during lightning is analyzed using electricitythermal- force sequence coupled model. It is enough to produce damage on material for the thermal stress that reached 226.9MPa. So it is necessary to consider the thermal stress in the lightning damage research.(4) The combination of Tsai-Wu failure criterion and Hashin failure criterion is proposed to determinate material damage, which is realized by secondary development. The residual strength of the lightning damage model is analyzed.Lightning damage on the tensile properties of the composites has a large impact byreducing about 6.67% of its tensile strength. However lightning damage on the compressive properties of the composites has a small impact by reducing only about1.64% of its compressive strength.