Acoustic Department, Bang & Olufsen, Peter Bangs Vej 15, DK-7600 Struer, Denmark.
J Acoust Soc Am. 2011 Feb;129(2):707-16. doi: 10.1121/1.3523305.
Plates stiffened with ribs can be modeled as equivalent homogeneous isotropic or orthotropic plates. Modeling such an equivalent smeared plate numerically, say, with the finite element method requires far less computer resources than modeling the complete stiffened plate. This may be important when a number of stiffened plates are combined in a complicated assembly composed of many plate panels. However, whereas the equivalent smeared plate technique is well established and recently improved for flat panels, there is no similar established technique for doubly curved stiffened shells. In this paper the improved smeared plate technique is combined with the equation of motion for a doubly curved thin rectangular shell, and a solution is offered for using the smearing technique for stiffened shell structures. The developed prediction technique is validated by comparing natural frequencies and mode shapes as well as forced responses from simulations based on the smeared theory with results from experiments with a doubly curved cross-stiffened shell. Moreover, natural frequencies of cross-stiffened panels determined by finite element simulations that include the exact cross-sectional geometries of panels with cross-stiffeners are compared with predictions based on the smeared theory for a range of different panel curvatures. Good agreement is found.
加肋板可以被建模为等效均质各向同性或各向异性板。用有限元法对这种等效的弥散板进行数值建模所需的计算机资源要远远少于对完整加肋板的建模。当许多加肋板组合在由许多板面板组成的复杂装配中时，这可能很重要。然而，虽然等效弥散板技术在平板方面已经得到很好的建立和最近的改进，但对于双曲加肋壳还没有类似的成熟技术。本文将改进的弥散板技术与双曲薄矩形壳的运动方程相结合，为加肋壳结构提供了使用弥散技术的解决方案。通过比较基于弥散理论的模拟的固有频率和模态形状以及强迫响应与带有双曲交叉加筋壳的实验结果，验证了所开发的预测技术。此外，还将包含带有交叉加筋的面板的精确横截面几何形状的有限元模拟确定的交叉加筋板的固有频率与弥散理论的预测进行了比较，涵盖了不同的面板曲率范围。发现吻合良好。
