基于SPH方法的鸟撞飞机风挡的数值模拟

SPH-Based Numerical Simulation of Aircraft Windshield Under Bird Impact

风挡抗鸟撞是飞机安全飞行的重要保证.文中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有限元分析模型,利用光滑粒子流体动力学法(SPH)耦合有限元法对圆弧风挡受鸟撞击的过程进行了数值模拟,计算得到风挡结构的变形、位移、应变、撞击力、应力、临界撞速、发生破坏的可能位置及其破坏方式等几方面的数据,并考察了SPH粒子疏密对计算结果的影响.研究表明,数值模拟结果与实验结果基本吻合;鸟撞整个过程约4ms,撞击中点、前1/3处和后1/3处,风挡发生破坏(包括安全破坏)的临界撞速分别约为(540±5)、(600±5)和(470±5)km/h;鸟撞过程中,风挡的位移与其厚度是同一量级,风挡的最大应变已达到10^(-2)量级;风挡首先发生破坏的位置在后弧框附近,然后向与风挡中线成45°角的方向发展;SPH粒子数越多,鸟体变形模态越好.

Bird impact resistance of windshield is most important for flight safety. In this paper, based on the experimental observation of aircraft arc windshield under bird impact, a finite element analysis model of arc windshield and bird body for a certain aircraft made in China is established, and the impact process is numerically simulated by means of the Smoothed Particle Hydrodynamics （SPH） coupling with the finite element method. Then, a series of data such as deformation, displacement, strain, impact force, stress, critical impact velocity, possible damage location, and mode of arc windshield are obtained. Moreover, the effect of SPH particle density on the calculation results is analyzed. It is found that （ 1 ） the simulated results basically accord with the experimental ones ;（2） the whole process of bird impact lasts about 4ms, and the critical impact velocities of windshield damage （ including safety damage） are （540 ±5）, （600 ±5） and （470 ±5） km/h at the middle point, the front 1/3 and the back 1/3 of the windshield, respectively; （3） the displacement and thickness of windshield in the impact process are of the same order of magnitude, and the maximum strain of windshield reaches 10-2 order of magnitude; （4） the damage of windshield first locates near the back arc frame, then expands towards 45°direction with respect to the windshield midline ; and （5） the deformation mode of bird body becomes better with the increase of SPH particles.