Global-Local Flexural-Torsional Buckling of Composite Laminated Beams

复合材料层合梁的全局-局部弯扭屈曲

• 批准号: 510739591
• 负责人: Professor Dr.-Ing. Christian Mittelstedt
• 金额: --
• 依托单位: Fachgebiet Konstruktiver Leichtbau und Bauweisen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/510739591?language=en
• 关键词: Global; Local; Flexural; Torsional; Buckling

Classical stability problems like global buckling (i.e. flexural buckling, flexural-torsional buckling, lateral buckling) as well as local buckling problems such as web or flange buckling of thin-walled isotropic beams have been understood and can be treated adequately using analytical or numerical methods. A significant number of open questions, however, exist when dealing with the stability behavior of shear deformable and anisotropic beams made of composite laminated materials. The present research proposal is thus devoted to the investigation of the flexural-torsional buckling problem of such composite laminated beams under consideration of simultaneous local buckling modes where the focus is on the development of highly efficient and accurate closed-form and semi-analytical methods. The simultaneous occurrence of local and global buckling modes is often termed as interactive buckling or global-local buckling and has been treated only scarcely in the open literature. The analysis methods that shall be developed in this research project are intended to incorporate all coupling effects as they are typical in composite laminates, as well as the influence of transverse shear deformations that have a significant influence on the buckling response of laminated structures which necessitates the use of higher order shear deformation theories. The research project will focus on the development of closed-form analytical and semi-analytical methods for the assessment of the flexural-torsional buckling of composite laminated beams under uniaxial compression considering local buckling modes wherein a hierarchical modelling concept will be employed by using several different laminate theories (Classical laminated plate theory as well as First-Order and Third-Order Shear Deformation Theory) for the local buckling modes. The analysis methods are based on energy formulations in conjunction with the Ritz method using adequate representations for all buckling degrees of freedom using series expansions. A comparison with finite element computations and reference results will serve as method verification. Systematic optimization routines using the methods of mathematical programming will be employed in order to highlight the optimization potential for composite laminated beams when interactive buckling is considered.

经典的稳定性问题，例如全球屈曲（即弯曲屈曲，弯曲的屈曲，侧向屈曲）以及局部屈曲问题，例如网络或薄壁各向同性束的法兰屈曲，可以使用分析或数值方法对其进行充分处理。但是，在处理由复合层压材料制成的剪切可变形和各向异性束的稳定性行为时，存在许多开放问题。因此，本研究建议致力于研究这种复合层压板的弯曲屈曲屈曲问题，即同时考虑的局部屈曲模式，其中重点是发展高效，准确的封闭形式和半分析方法。局部和全球屈曲模式的同时出现通常被称为互动屈曲或全球本地屈曲，并且在开放文献中几乎没有被治疗。该研究项目中应开发的分析方法旨在纳入所有耦合效应，因为它们在复合层压板中是典型的，以及对层压结构的屈曲响应有重大影响的横向剪切变形的影响，这需要使用高阶剪切变形理论。该研究项目将着重于开发封闭形式的分析和半分析方法，以评估复合层压梁在单轴压缩下的弯曲扭曲屈曲屈曲，考虑到本地屈曲模式，其中层次建模概念将通过使用几种不同的层压板理论（经典的层压板理论以及本地屈曲理论和第三级阶数）来实现层次结构概念，以实现。该分析方法基于能量公式与丽思方法结合使用串联扩展的所有自由度的适当表示。与有限元计算和参考结果的比较将作为方法验证。将使用数学编程方法进行系统的优化例程，以突出当考虑交互式屈曲时的复合层压梁的优化潜力。