Specimen and experimental method for measuring shear modulus of flexible skin of morphing aircraft

Abstract

The invention discloses a sample for measuring the shear modulus of a flexible skin of a variant aircraft and an experimental method, and relates to the technical field of structural mechanical performance testing. A topology optimized structure and a clamping structure are integrally formed through a 3D printing technology, unavoidable preparation errors produced by manual preparing samples are avoided, good sample stability is ensured, the consistency of a load transfer path is ensured, and the consistency of the experiment is further ensured. The clamping structure can effectively convert the tensile load of a testing machine into the shear load on the topology optimized structure, a unit cell shear test is realized, good experimental results are obtained, and the problem of testing ofshear mechanical properties of a flexible skin structure of the variant aircraft is solved. The installation and disassembly of a fixing structure are simple and easy to operate, and it is ensured that the shear modulus measuring sample of the skin optimized structure does not generate initial deformation during the clamping process, so that the experimental accuracy is further improved.

Description

technical field [0001] The invention relates to the technical field of structural mechanical performance testing, in particular to a sample and an experimental method for measuring the shear modulus of a flexible skin of a variant aircraft. Background technique [0002] The morphing aircraft has good flight performance in a large airspace range, which solves the problem that traditional aircraft can only achieve the optimal aerodynamic characteristics of a single design point, and becomes the basis for the breakthrough development of a new generation of aerospace vehicles. The flexible skin, as an important deformation part of the airfoil of the variant wing, needs to have certain flexibility to realize the smooth transition between different airfoils, and at the same time bear the aerodynamic load during flight. Composite flexible skin based on cellular support structure is one of the most promising schemes, but usually the traditional honeycomb structure or zero Poisson's ...

AI Technical Summary

Problems solved by technology

Composite flexible skin based on cellular support structure is one of the most promising schemes, but usually the traditional honeycomb structure or zero Poisson's ratio structure is used as the support body, which cannot meet a variety of work requirements in an optimal working state, so it is necessary to The topology optimization design is carried out for the flexible skin cell structure, and the optimal cell support structure of the flexible skin of the variant aircraft is obtained under different load conditions and constraints

[0003] The feasibility of the topology optimization design theory and the validity of the optimization results must be verified by corresponding experiments. Most of the existing technologies are aimed at the axial tensile performance test. When changing the camber of the airfoil and other tasks, the flexible skin not only bears the effect of axial tensile load, but the shear force on the skin structure is considerable, so it is far from enough to test the axial tensile performance only

The geometric configuration of the flexible skin structure of the variant aircraft designed based on topology optimization technology is complex, and its mechanical properties cannot be obtained by traditional shear mechanics experimental methods. The prior art lacks testing methods for its shear properties, especially the shear elastic modulus. and testing methods, unable to fully verify the effectiveness of topology optimization structures, which limits the practical application and development of topology optimization skins in the field of variant aircraft

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