水陆两栖飞机动载荷特性数值分析

Dynamic load characteristics of large firefighting amphibious aircraft

现代飞机设计过程中,要考虑机体不同部位的动态载荷特性。根据大型灭火水陆两栖飞机使用模式的特殊性,利用流固耦合技术分析飞机着水时重心的过载和船底压力响应,利用气动力最小状态拟合技术分析飞机投水和退场爬升时的动载荷,利用模态法原理和功率谱模型分析飞机在离散突风和连续紊流作用下的动载荷。结果显示,对于大型灭火水陆两栖飞机,其着水载荷计算要考虑着水姿态、前飞速度、下沉速度、水面波浪的影响;飞机投水时机体的动载荷响应量不大,但大迎角退场时、投水动载荷显著增大;飞机遭遇突风时机体的动载荷量级与静载荷相当,应对机体强度进行补充校核。分析结果为大型灭火水陆两栖飞机的结构设计提供了依据。

Dynamic load characteristics of different parts in aircraft should be considered in the design of modern aircraft. In view of the particularity in usage mode of large firefighting amphibious aircraft,gravity center overload and pressure response of hull bottom during water landing w ere analyzed by fluid-solid coupling method,dynamic loads during fire-fighting water dropping and climbing to departure for aircraft were investigated based on the aerodynamic minimum-state fitting technology,and dynamic loads under the action of discrete gust and continuous turbulence were calculated using modal method principle and power spectrum model. Results show that calculation on water landing load for large fire-fighting amphibious aircraft should involve the effects of landing posture,forward flight speed,sinking velocity and water surface wave. The response of dynamic load during fire-fighting water dropping is not large,whereas it increases remarkably during climbing to departure with high angle. Dynamic load under discrete gust is the same magnitude as static load,but structure strength should be supplemented and checked. The results provide some references for structural design of large firefighting amphibious aircraft.