单轴压缩载荷下夹层梁结构屈曲及皱曲模拟研究

In-Depth Study on Buckling and Wrinkling of Foam-Cored Sandwich Beam under Uniaxial Compression Load

泡沫夹层结构以其较高的比刚度及比强度特性在航空航天等领域具有巨大的应用潜力,但当夹层结构作为主承力部件承压时可能带来复杂的屈曲及皱曲稳定性问题。文章基于有限元分析软件Ansys,建立了铝面板泡沫夹层梁结构的二维有限元模型,研究了夹层梁结构在单轴压缩载荷下结构临界失稳载荷与屈曲失效模态的内在关系,并分析了芯材厚度、芯材弹性模量等参数对夹层结构稳定性的影响规律。研究结果表明:芯材-面板的厚度比及弹性模量比对夹层结构的屈曲失效模态具有决定性作用,增加芯材厚度及选用较高弹性模量的芯材,可有效提高泡沫夹层结构的临界失稳载荷,文中研究结果可为泡沫夹层结构的优化设计及工程应用提供理论依据。

The foam-cored sandwich structure is used widely in the fields of aeronautics and aerospace for having the advantages of higher stiffness ratio and strength ratio. The main propose of this paper is to explore the stability problem of sandwich structure used in the UAV （ Unmanned Aerial Vehicle） , in which the thick or soft core usually leads to the short-wave buckling mode, namely wrinkling. Sections 1 and 2 of the full paper explain and evaluate our study mentioned in the title, which we believe gives some in-depth results. The core of sections 1 and 2 consists of： （ 1 ） in order to simulate the overall buckling and wrinkling of the sandwich beam subjected to uniaxial compression load, a two-dimensional finite element model of foam-cored sandwich beam with aluminum face-sheets was developed in Ansys software; （2） the critical instability load, the buckling/wrinkling control mode, and the inherent relation between them were calculated and analyzed based on the model; （3） the simulation studies were carried out to investigate the influences of the main structural parameters on the stability of the sandwich beam, such as the core thickness, the core elastic modulus and the thickness ratio of core-to-sheet. The research results, given in Figs. 4 though 7 and Tables 2 and 4, and their analysis show preliminarily that ： （ 1 ） the critical instability load of foam-cored sandwich beam increases with increasing core thickness and elastic modulus; （2） the thickness ratio and elastic modulus ratio of core-to-sheet are key parameters to determine which kind of three instability modes finally occurs, e.g. overall buckling, symmetrical wrinkling and antisymmetrical wrinkling. Section 3 gives our preliminary conclusions in more detail with some suggestions for optimization design and engineering application of the foam-cored sandwich structure.