Stringer frame stiffened shell structures are frequently used as primary structures of aerospace applications. They show a high load carrying capacity combined with a low mass. The design is complex because of three reasons: Firstly, there exists a high number of design variables making the design of such a shell very demanding using numerical methods such as the finite element method. Secondly, such a shell can exhibit different local instabilities before failing globally. And thirdly, the calculation of the panel instability load is not fully possible yet, especially when using closed and therefore torsional stiff stringer stiffener. Within this paper, a novel approach for the calculation of the panel instability load of stringer frame stiffened shell structures with torsional stiff stringer under axial compression is introduced. The novelty is expressed in the consideration of transverse shear and prebuckling deformations. It is shown that in contrast to unstiffened shell structures both aspects cannot be neglected and have a significant influence on the buckling load. The classical smearing method is expanded and used in a consecutive utilization of the Ritz method to calculate the panel instability load. Geometrically non-linear finite element analyses are performed to validate the novel approach and establish a domain of applicability. The suggested approach delivers excellent results for the prediction of the panel instability load.

纵梁加劲壳结构经常用作航空航天应用的主要结构。它们显示出高承载能力和低质量。由于以下三个原因，设计很复杂：首先，存在大量的设计变量，使得使用数值方法（例如有限元法）对这种壳体的设计要求很高。其次，这样的外壳在全局失效之前会表现出不同的局部不稳定性。第三，还不能完全计算面板的不稳定性载荷，尤其是在使用封闭的因而是扭转的刚性纵梁加劲肋时。在本文中，引入了一种新的方法来计算在轴向压缩下具有扭转刚度桁条的桁架框架加劲壳结构的面板失稳载荷。在考虑横向剪切和预屈曲变形时可以表达新颖性。结果表明，与未加劲的壳结构相比，这两个方面都不能忽略，并且对屈曲载荷有重大影响。扩展了经典的涂抹方法，并连续使用了Ritz方法来计算面板的不稳定性载荷。进行几何非线性有限元分析以验证新方法并建立适用范围。所建议的方法可为面板失稳载荷的预测提供出色的结果。扩展了经典的涂抹方法，并连续使用了Ritz方法来计算面板的不稳定性载荷。进行几何非线性有限元分析以验证新方法并建立适用范围。所建议的方法可为面板失稳载荷的预测提供出色的结果。扩展了经典的涂抹方法，并连续使用了Ritz方法来计算面板的不稳定性载荷。进行几何非线性有限元分析以验证新方法并建立适用范围。所建议的方法可为面板失稳载荷的预测提供出色的结果。