用SPH和有限元方法研究鸟撞飞机风挡问题

鸟与飞行中的飞机相撞是飞机结构损坏的重要因素,严重时会引发机毁人亡的灾难性事故。对高速低空飞行的军用飞机而言,风挡部分抗鸟撞的研究对保证飞行安全尤其重要。基于飞机圆弧风挡受鸟体撞击的实验观察,建立了国产某型军用飞机圆弧风挡及鸟体的计算模型,采用LS-DYNA3D中有限元和光滑粒子流体动力学(SPH)耦合的数值分析方法,对某飞机圆弧风挡受鸟体撞击的过程进行了数值模拟。计算结果得到了风挡结构的变形、位移和应变等几方面的数据,与实验结果基本吻合。同时,给出了500～650km/h速度范围内的撞击力和应力时程曲线、风挡发生破坏的临界撞速、圆弧风挡经受鸟体撞击时发生破坏的可能位置及其破坏方式。最后,与鸟体采用任意拉格朗日(ALE)和无网格伽辽金方法(EFG)进行了对比,验证了SPH方法在分析鸟撞问题中的优越性。研究结果为风挡的安全设计和研制新机型提供了有价值的数据。

A Study of Bird Impact on Aircraft Windshield Using SPH and Finite Element Method

The clash between flying birds and airplanes frequently results in damage of aircraft structures which could even lead to aircraft crash and death of crew members in the most disastrous cases.Investigation on the windshield resistance to bird impact is therefore crucial to ensure the safe flight of high-speed low-altitude military aircraft.Based on the experimental observation of bird impact on aircraft arc windshields, a computational model of an arc windshield and bird for a certain type of aircraft made in China is established.Issues on the arc windshield impacted by birds are studied using smoothed particle hydrodynamics (SPH) and the finite element method (FEM) provided by LS-DYNA3D.Results including the deformation, displacement and strain of the arc windshield are obtained through numerical simulation, which agree well with the experimental data.More useful conclusions, such as the impact force history curve and stress history curve under impact velocities in the range of 500-650 km/h, the critical impact velocity which can lead to damage of the windshield, possible damage locations and modes of the windshield after impacted by birds, are drawn from the numerical simulation.Finally, a comparison of the arbitary Lagrange Euler (ALE) and element free Galerkin (EFG) methods with the SPH for bird impacts verifies that the SPH method is feasible and efficient for analyzing bird impact problems.The research results can provide valuable data for the design and manufacture of reliable windshields.