Department of Architecture and Civil Engineering, City University of Hong Kong, Kowloon Tong, Kowloon, Hong Kong.
PLoS One. 2018 Jul 3;13(7):e0199159. doi: 10.1371/journal.pone.0199159. eCollection 2018.
This study addresses the nonlinear structure-extended cavity interaction simulation using a new version of the multilevel residue harmonic balance method. This method has only been adopted once to solve a nonlinear beam problem. This is the first study to use this method to solve a nonlinear structural acoustic problem. This study has two focuses: 1) the new version of the multilevel residue harmonic balance method can generate the higher-level nonlinear solutions ignored in the previous version and 2) the effect of the extended cavity, which has not been considered in previous studies, is examined. The cavity length of a panel-cavity system is sometimes longer than the panel length. However, many studies have adopted a model in which the cavity length is equal to the panel length. The effects of excitation magnitude, cavity depth, damping and number of structural modes on sound and vibration responses are investigated for various panel cases. In the simulations, the present harmonic balance solutions agree reasonably well with those obtained from the classical harmonic balance method. There are two important findings. First, the nonlinearity of a structural acoustic system highly depends on the cavity size. If the cavity size is smaller, the nonlinearity is higher. A large cavity volume implies a low stiffness or small acoustic pressure transmitted from the source panel to the nonlinear panel. In other words, the additional volume in an extended cavity affects the nonlinearity, sound and vibration responses of a structural acoustic system. Second, if an acoustic resonance couples with a structural resonance, nonlinearity is amplified and thus the insertion loss is adversely affected.
本研究采用新版本的多级残差谐波平衡法解决非线性结构扩展腔相互作用的模拟问题。该方法之前仅被用于解决一个非线性梁问题。这是首次使用该方法解决非线性结构声问题的研究。本研究有两个重点：1）新版本的多级残差谐波平衡法可以生成之前版本中忽略的更高阶非线性解；2）检验之前研究中未考虑的扩展腔的影响。面板-腔系统的腔长有时会超过面板长度。然而，许多研究采用的模型中腔长等于面板长度。针对各种面板情况，研究了激励幅度、腔深、阻尼和结构模态数量对声振响应的影响。在模拟中，本谐波平衡解与经典谐波平衡法得到的解吻合较好。有两个重要发现。首先，结构声系统的非线性高度依赖于腔尺寸。如果腔尺寸较小，则非线性较高。大的腔体积意味着从源面板传递到非线性面板的刚度较低或声压较小。换句话说，扩展腔中的附加体积会影响结构声系统的非线性、声振响应。其次，如果声学共振与结构共振耦合，则非线性会被放大，从而导致插入损耗受到不利影响。
