中文摘要：

基于径向形函数可任意变阶的映射波包络声学无限元法，以无限长圆柱壳体为研究对象，用数值计算方法对其结构外声场进行研究分析，并与其解析解进行对比，结果表明：两者之间能够较好地吻合，从而验证了映射变阶波包络声学无限元法在计算结构声辐射中的可行性，且具有效率高、精度好等优点。在此基础上，本文还讨论虚拟极点位置对声辐射的影响，通过对比四极子极点偏心声压值发现：极点存在偏心时，对实际工程问题有不利影响，但随声学无限单元阶数的增加，误差会减小。

英文摘要：

This paper is on the basis of a variable order in radial direction infinite acoustic wave envelope element （WEE）. Numerical method is adopted to study the sound radiation pressure of an infinitely long cylinder as the subject investigated, and obtained results agree well with analytic solutions. The research presents that the variable order infinite acoustic wave envelope element which can be successfully applied to sound radiation pressure computation field is proven. The WEE has obvious advantages such as high efficiency and high degree of accuracy. Based on the above results, this paper also describes the influence of virtual sound source’s location in sound radiation, and it can be concluded that the decentration of virtual source has bad effects on the actual project by comparing the sound pressure values of quadrapole. However, with the increased orders of infinite acoustic element, the inaccuracy of sound pressure is decreasing.