船舶基座阻抗计算的梯度网格模型方法

A Gradient Grid Model for Impedance Calculation of Ship Foundation

根据振动波的衰减特性,提出一种新型有限元梯度网格计算模型,基于计算频段范围以及基座结构特性对全船结构采用不同尺寸有限元网格进行离散,实现基座阻抗的全频段准确高效计算.某船各类基座阻抗计算结果表明,相比于全船均匀细化网格模型,梯度网格模型阻抗计算效率高,计算精度相当;相比于局部结构模型,计算效率相当,计算精度可提高大约2dB.梯度网格模型方法对于各类典型基座的阻抗计算具有广泛适用性,并进一步证明了阻抗的精确计算对振源设备载荷反演及结构水下辐射噪声计算精度有着重要影响.

Impedance of foundation is a significant parameter for structural and acoustical design for a ship.According to attenuation of the vibration wave,a gradient grid model was proposed.The ship is discredited into elements with different sizes,and then the foundation impedance could be analyzed accurately and efficiently.The results show that this model has a higher efficiency than the entirely refined model under equivalent accuracy.Compared with the truncated model,accuracy of the present model can be improved by about 2 dB.The model can be widely applied to various types of foundations.It is shown through the given example that accurate estimation of the impedance has a huge influence on underwater radiation of noise.