能量有限元法在船舶结构中的应用

为了解决舰船结构的振动噪声预报及其控制问题,以能量密度为变量,获得了薄板结构受激励产生弯曲振动时的能量密度控制方程,并得到了控制方程的有限元解.用该方法对简单的薄板结构进行了验证计算,并对一舰船的基座结构进行了计算分析.由基座结构的能量密度随频率的变化规律得知,在高频范围内,能量比值随频率增加而缓慢减小.改变基座结构的板厚及阻尼系数值,可以使结构的能量密度值明显降低.计算结果表明,由能量有限元法得到的结构中能量密度的比值与实验结果吻合较好,从而验证了本文所用的能量有限元法是一种有效可靠的分析高频振动噪声问题的方法.

Application of energy finite element method in ship structures

To better forecast and control the structural vibration and noise of naval vessels and other kind of ships,the energy finite element method was introduced.Taking energy density as the variable,the governing equation for transverse vibration of the thin plate was derived from the classical displacement solutions,and the energy density equation of two-dimensional coupling structures was solved by Galerkin weighted approximation.The method was verified by calculating a simple coupled thin plate and was used to predict the energy density distribution for the engine foundation of a frigate ship.Results indicate that at high frequencies,the ratio of energy density decreases slowly with the increase of frequency.The change of plate thickness and damping coefficient can reduce the structural density evidently.The comparison of calculation results with experimental results shows that there is a good agreement between them,which proves that the energy finite element method is efficient and reliable for predicting vibration and noise at high frequencies.