Abstract:

Because of the difficulty to actuate the large structures in low frequency region, the mechanical impedance data of the large structures at low frequency has small coherence factor and low reliability. In this paper, a finite element code is used to establish an FE model for large cabin structure, and the mechanical impedance of a submarine cabin base in the low frequency region is calculated. The numerical results are compared with those of experimental measurement and theoretical assessment. The feasibility for forecasting the mechanical impedance characteristics of the base in the low frequency region by means of the finite element method is evaluated. The disadvantage of the low reliability of the measured mechanical impedance data of the cabin base at the low frequency is improved. This method is valuable for engineering application.

Key words: vibration and wave, base, low frequency, FEM, mechanical impedance

摘要：

由于大型或重型结构在低频段难以激励起来，低频时大型结构的机械阻抗数据相干系数小，可信度较低。为了弥补这个缺点，使用有限元软件对大型舱段结构进行建模，计算了潜艇舱段基座低频段的机械阻抗，并与实测值和理论估算值进行对比，结果令人满意。本文评价了使用有限元方法在低频段对基座进行阻抗特性预报的可行性，弥补了低频段舱筏基座实测机械阻抗数据可信度较低的不足，具有一定的工程应用价值。

关键词: 振动与波, 基座, 低频, 有限元, 机械阻抗