接闪阳极参数对雷电弧材料损伤数值分析的影响OA北大核心CSTPCD

Lightning is a high-intensity electromagnetic pulse discharge phenomenon that occurs frequently in nature.Lightning arc discharges with the multi-source impacts from a combination of electrical-magnetic-thermal-force infliction can seriously damage materials,meanwhile the large amount of electric charge transfer also generates huge Joule heat inside the material,which will further increase the level of damage.Numerical simulation and prediction techniques for the damage results of skin materials to direct lightning strikes can provide a reference for the design of skin structures and the associated lightning protection. Up to date,influence of the tested material parameters on the numerical analysis of the arc-material interactions has not been addressed in the regimes of direct lightning damage.To this end,taken the commonly used metal and composite skin materials for aircraft as the object of study,the numerical analysis is carried out based on the magneto-hydrodynamic(MHD)theory of thermal plasma arc and damage response of materials in a cathode-arc-anode domain.The multi-field analysis of a coupling of electric-magnetic-thermal-force equations is implemented to discuss the influence of the tested material parameters on the arc-material interactions,The numerical analysis equations mainly contain the conservation of mass,conservation of momentum and conservation of energy equations describing the arc fluid,and the coupling of Maxwell's equations describing the electromagnetic field distribution and the heat conduction equations describing the second type of boundary conditions.At the same time,coordinate transformation and solution of the above control equations are required to achieve the joint calculation of each equation.By simulating the lightning arc material damage test,the damage depth of 3003 aluminium alloy specimen under the action of long duration lightning current is calculated as 3.52 mm,and the test measurement value is 3.31 mm,with a relative error of 6.2%.The calculated temperature rise of the backing plate was 564.1 K and the measured value was 507.7 K,with a relative error of 11.1%.The calculated temperature rise of the specimen was greater than the measured result due to the influence of response time,light environment and other factors during the field test measurement.The test verified that the model built by the research has a certain accuracy,which can realize the simulation and analysis of the damage process of electric arc material. By comparing the distribution of Lorentz force,magnetic induction intensity,and current density of the cathode-arc-anode structure with different material parameters,this work found that when the electrical and thermal conductivity of the anode material changes,the distribution of current and energy on the arc-material interface and their interfacial coupling process will change.Amplitude of the Lorentz force,magnetic induction strength and current density can alter 622.2%,172.5%,63.5%,respectively,with the electrical and thermal conductivity changing of 0.1 to 20 times.Meanwhile,their peak position on the surface of anode change-54.8%,59.4%,-53.1%,respectively.The anisotropy of the composite material lead to the asymmetrical response of the heat transfer and current density in each direction during the arc action,which accounts for the nonlinear dependence of the arc-material interactions to the changing electrical and thermal conductivity,which exhibite more complex results compared to the situation of metallic materials. This work report the existence of changing parameters in the arc modelization with tested material parameters and demonstrate how these material parameters affect the numerical results of the arc-material interactions.The conclusions draw attention to the modeling study of the complex arc-material interactions and help improve the accuracy in the numerical prediction of materials'damage response to lightning strikes.