民机起落架摆振仿真与虚拟适航验证

Shimmy Simulation and Virtual Verification for Civil Aircraft Landing Gear Airworthiness Certification

起落架摆振稳定性是现代民机研制和适航认证的重要关注问题。针对民用飞机复杂的前起落架系统,建立三维简化动力学仿真模型,分别模拟不同的摆振试飞场景-典型的摆振滑行速度、重量/重心和跑道障碍物摆振激励方式,开展刚柔耦合起落架结构的摆振特性分析。仿真结果验证飞机起落架在正常构型下的稳定性,分别评估起落架减摆阻尼、轮胎松弛长度和侧偏刚度对摆振稳定特性的影响。通过对适用的中国民航适航规章进行解析,并综合民机型号起落架摆振适航审定实践提出包含摆振适航需求捕获和仿真分析、虚拟试验及物理试验(设备鉴定试验、起落架系统台架试验和摆振试飞)的摆振稳定性验证与适航审定的“积木模型”。实例分析表明运用虚拟验证技术辅助摆振适航验证和符合性判定的可行性。

Landing gear shimmy is an important issue in modern civil aircraft development and airworthiness certification. For the complex nose landing gear of a civil aircraft, the three-dimensional(3D) simplified dynamic model is developed and shimmy characteristic parameters of the rigid-flexible coupling structures are obtained under different simulated shimmy flight test scenarios-typical taxing speed, weight/center of gravity and runway plank excitation. The landing gear stability in normal configuration is validated. The influence of the shimmy damping, tire relaxation length and cornering stiffness on the stability is analyzed respectively. Interpretation and induction of applicable Chinese Civil Aviation Regulations for shimmy, besides landing gear shimmy airworthiness certification practice are illustrated. A reasonable airworthiness verification and certification "Building Block Model", which includes airworthiness requirements capture, simulation, virtual test and test(equipment qualification test, landing gear system laboratory test and shimmy flight test), is proposed. The civil aircraft shimmy case study demonstrates the feasibility of virtual verification technology to assist the shimmy compliance finding.