Design of z-shaped reinforced panels of composite materials under compression and shear

Abstract

When designing thin-walled aircraft structures, as a rule, the main limitations are associated with ensuring stability. The objects of research in this work are composite z-shaped reinforced panels of the wing box of an aircraft. For the early stages of the design of load-bearing panels, it is necessary to evaluate the weight of the design decisions made, taking into account possible defects. The paper proposes an analytical technique for designing reinforced panels, taking into account the use of the condition of uniform stability and the presence of possible regulated defects in the skin that may occur in further operation. The task of determining the parameters of panels of minimum weight is reduced to minimizing the function of one variable, which is the ratio of the height to the reinforcement step. To take into account the indicated regulated defects, parametric studies were carried out using the finite element method, on the basis of which refinement coefficients were added to the analytical ratios of the stiffness parameters of the reinforced panels. The paper presents the results of studies of orthotropic panels with defects in the form of through holes under loading with compressive and tangential forces. The results are presented in the form of graphs that show possible changes in the critical stresses of thin skins with defects.