It is known that the variable-order infinite acoustic wave envelope element (WEE) must be coupled with finite element method (FEM) by element matching for computing acoustic field radiated from radiators with complex geometric shapes. Therefore, the WEEs have to be reconstructed when the finite elements are refined or changed. To overcome the shortcoming, the element-free Galerkin (EFG) coupled with improved WEE (IWEE) method is presented to compute acoustic problems in the infinite domain. The continuity and compatibility of the acoustic pressure are maintained by IWEE that is composed of a standard WEE and a fictitious finite mesh. A key feature of the method is the introduction of the EFG method which is employed to eliminate the element matching and improve the accuracy of predicted acoustic pressure. The factors that affect the performance of the method are investigated by numerical examples, which include shape function construction, the weight function and the size of the influence domain. The numerical results show that the present method provides more accurate results compared to the coupled FEM-WEE method. The experimental results show that the method is very flexible for acoustic radiation prediction in the infinite domain.

中文翻译：

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外声学问题的无元伽辽金耦合改进无限元法

众所周知，变阶无限声波包络元（WEE）必须通过元素匹配与有限元法（FEM）耦合，以计算从具有复杂几何形状的辐射体辐射的声场。因此，当有限元被细化或改变时，WEEs 必须被重建。为了克服这一缺点，提出了无元素伽辽金（EFG）结合改进的WEE（IWEE）方法来计算无限域中的声学问题。由标准 WEE 和虚拟有限网格组成的 IWEE 保持声压的连续性和兼容性。该方法的一个关键特点是引入了 EFG 方法，该方法用于消除元件匹配并提高预测声压的准确性。通过数值例子研究了影响方法性能的因素，包括形状函数构造、权重函数和影响域的大小。数值结果表明，与耦合 FEM-WEE 方法相比，本方法提供了更准确的结果。实验结果表明，该方法对于无限域的声辐射预测非常灵活。