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针对含多设计参数的典型民机机身下部结构耐撞性设计,提出了一种设计方法,该方法以最小化客舱地板的初始加速度峰值与最大化参考压溃状态的结构内能为优化双目标,通过Kriging模型对结构的冲击响应进行预测,采用非支配排序遗传算法Ⅱ(NSGA-Ⅱ)对双目标进行优化,进而由Nash-Pareto策略获得最优方案。为了得到最优设计方案,同时研究设计参数对机身结构耐撞性的影响,提出最大化期望提高与最大化预测方差同步加点准则建立代理模型。采用该设计方法,以典型民机机身下部结构设计问题为算例,对客舱地板支撑结构、货舱地板和泡沫构件形状参数进行优化。结果表明,相对原始设计客舱地板的加速度峰值降低约18.3%,次高加速度峰值也得到有效降低,改善了机身结构的耐撞性;Kriging模型预测响应与有限元分析结果误差小于1%,说明了设计方法的有效性。
Aiming at the design of the crashworthiness of the lower fuselage structure of a typical civil aircraft with multiple design parameters, a design method is proposed to minimize the initial peak acceleration of the cabin floor and maximize the internal collapse of the reference. The objective is to predict the impact response of the structure by the Kriging model. The non-dominant ranked genetic algorithm Ⅱ (NSGA-Ⅱ) is used to optimize the bi-objective, and then the optimal scheme is obtained by the Nash-Pareto strategy. In order to obtain the optimal design scheme and to study the influence of design parameters on the crashworthiness of the fuselage structure, aiming at the maximization of the expected increase and the maximization of the prediction variance, a set of proxy model is established. With this design method, taking the design of the lower structure of the typical fuselage of civil aircraft as an example, the shape parameters of the cabin floor support structure, the cargo floor and the foam component are optimized. The results show that the peak value of acceleration is reduced by about 18.3%, the peak of secondary acceleration is reduced effectively, and the crashworthiness of fuselage structure is improved. The error between Kriging model prediction and finite element analysis is less than 1% The effectiveness of the design method.