Reliable and practicable analysis methods for the postbuckling behaviour of thin composite plates and shells with longitudinal stiffeners under complex loading conditions

在许多采用加强板和壳形式的薄壁结构的技术应用中（即航空航天，海洋工程，土木工程和一般轻型工程），过去几十年已经看到了从传统金属结构到复合材料应用的革命性转变，例如以纤维增强塑料的形式。通常，复合材料结构以薄层结构的形式应用，即所谓的层压板。很自然地，由于薄壁的性质，这种层压复合材料结构的分析和设计需要对其稳定行为进行深入的分析，而复合材料稳定行为的研究仍然是一个相当新的领域，仍然存在许多悬而未决的问题，这是本研究计划的重点。对于在单轴和双轴压缩载荷、剪切载荷、横向压力及其组合下具有各种加筋模式（使用开型和闭型加筋）和边界条件的板壳，应结合ritz方法，在充分计算屈曲和后屈曲模态的基础上，开发用于评估屈曲和后屈曲行为的闭式解析和半解析分析方法。

In many technical applications in which thin-walled structures in the form of stiffened plates and shells are employed (i.e. aeronautics and astronautics, marine engineering, civil engineering, and general lightweight engineering), the last decades have seen a revolutionary shift from traditional metallic structures to the application of composite materials, e.g. in the form of fiber reinforced plastics. Very often, composite structures are being applied in the form of thin layered structures, so-called laminates. Quite naturally, due to their thin-walled nature the analysis and design of such laminated composite structures requires an in-depth analysis of their stability behavior where the investigation of the stability behavior of composite materials is still a rather new field where a good number of open questions still exists the investigation of which is the focus of the present research proposal. For plates and shells with various stiffening patters (using open-profile and close-profile stiffeners) and boundary conditions under uniaxial and biaxial compressive load, shear load, transverse pressure and the combinations thereof, closed-form analytical and semi-analytical analysis methods for the assessment of the buckling and postbuckling behavior shall be developed, based on adequate formulations for the buckling and postbuckling modes in conjunction with the Ritz-method.