Ivansson Sven M
Department of Underwater Research, Swedish Defence Research Agency, SE-164 90 Stockholm, Sweden.
J Acoust Soc Am. 2014 Jun;135(6):3338-51. doi: 10.1121/1.4876185.
Global optimization methods can be used to numerically determine optimal design parameters for an object. However, this does not by itself give a good appreciation of other parameter choices that may be almost as good and even preferable from other points of view. In the present paper, Markov-chain Monte Carlo methods are used to go beyond the optimal solution and create an ensemble of object models in parameter space that covers a set of favorable models uniformly. In direct analogy with applications to Bayesian inversion with determination of an unknown posterior probability density, projections of the model ensemble onto parameter axes and planes are used to exhibit parameter sensitivities and dependencies. Design of anechoic rubber coatings, with cylinder cavities having axes in a lateral direction, is considered as a particular application. The anechoic effect is evaluated by the efficient layer-multiple-scattering method, which is extended to handle cylinder scatterers of noncircular cross sections and mixed types. As anticipated by computed scattering and absorption cross sections for an isolated cavity, the favorable coatings have oblate cavity cross-section shapes, which is useful to achieve good low-frequency reflection reduction with a thin coating.
全局优化方法可用于数值确定物体的最优设计参数。然而，这本身并不能很好地评估其他可能几乎同样好甚至从其他角度来看更优的参数选择。在本文中，马尔可夫链蒙特卡罗方法被用于超越最优解，并在参数空间中创建一组均匀覆盖一组有利模型的物体模型集合。与用于确定未知后验概率密度的贝叶斯反演应用直接类似，模型集合在参数轴和平面上的投影用于展示参数敏感性和依赖性。具有横向轴线的圆柱腔的消声橡胶涂层设计被视为一个具体应用。通过高效的层多次散射方法评估消声效果，该方法被扩展以处理非圆形横截面和混合类型的圆柱散射体。正如孤立腔的计算散射和吸收横截面所预期的那样，有利的涂层具有扁圆形的腔横截面形状，这对于用薄涂层实现良好的低频反射降低很有用。
