关键词: 复合材料, 机身壁板, 试验装置, 应变误差矩阵, 试验载荷系数, 多维极值优化

Abstract:

Aiming at the problem of load prediction in the strength test of composite fuselage panel of civil aircraft， we construct an optimization model of the test load based on the strain error matrix， and predict the test load using the multi-dimensional minima optimization algorithm. Firstly， based on the load form of the fuselage panel in the test device， the finite element model of the fuselage panel and the test device was established， and the strain matrix of the fuselage panel under each test reference load calculated. Secondly， the fuselage panel strain error matrix was constructed based on the difference between the strain matrices of the fuselage panel under the full fuselage load state and the test state， and considering the weighting coefficients of each element in the matrix. With the minimum sum of squares of all terms in the strain error matrix as the objective， each reference load coefficient as the optimization variable， and the upper and lower limits of each reference load coefficient as the constraints， the reference load coefficient optimization function was constructed. The optimization function was then processed unconstrained based on the penalty function method， and the reference load coefficients obtained by the steepest gradient method. Finally， based on the optimized load， the strain of the fuselage panel under the composite load of the test was calculated. Compared with the strain of the fuselage panel under the full fuselage load， the distribution trend of the strain was basically the same with the strain error within 10%， proving that this method can provide support for the determination of the test load of the fuselage panel.

Key words: composite material, fuselage plate, test device, strain error matrix, test load factor, multi-dimensional extreme value optimization