﻿ 双层壳体缩比模型材料阻尼相似研究
 舰船科学技术  2018, Vol. 40 Issue (12): 33-36 PDF

1. 哈尔滨工程大学 水声学院，黑龙江 哈尔滨 150001;
2. 大连测控技术研究所，辽宁 大连 116013

Similar study on material damping of double shell scale model
ZHU Ling-guo1,2, ZHAO An-bang1, LIU Wen-zhang2, CAO Qing-gang2, YANG Bao-shan2
1. College of underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China;
2. Dalian Scientific Test and Control Technology Institute, Dalian 116013, China
Abstract: Acoustic similarity is the base of scaled model tests of underwater target. Because the scale similarity of target external lines can only reflect the echo characteristics of geometric highlights, and the echo characteristics of elastic highlights closely related to materials can not be completely simulated. In order to effectively use the scale model to simulate the actual submarine echo, the damping similarity of the material is studied on the basis of the similarity between the external line type and the thickness. Based on the theoretical model of double layer spherical shell and cylindrical shell in water, the influence of material loss on the similarity between two shell models and prototypes when making the same material is studied. The influence of damping of different metal materials on target strength is studied. The theoretical analysis and numerical calculation show that the loss factor of metal material has little influence on the acoustic similarity of the scale model.
Key words: acoustic similarity     target strength     material loss
0 引　言

1 缩比模型材料声学相似 1.1 钢材阻尼对目标强度的影响

 图 1 阻尼对球壳目标强度的影响 Fig. 1 Influence of damping on target strength of spherical shells

 图 2 阻尼对柱壳目标强度的影响 Fig. 2 Influence of damping on target strength of cylindrical shells

 ${f_\infty }({{\text{π}}} ) = {f_\infty }^{rig}({{\text{π}}} ) + {f_\infty }^{ur}({{\text{π}}} ){\text{，}}$ (1)

 ${f_\infty }^{rig}({{\text{π}}}) = \left| {\frac{2}{{\sqrt {{{\text{π}}} {k_1}a} }}\sum\limits_{n = 0}^\infty {{{( - 1)}^n}{\varepsilon _n}\left( - \frac{{{J_n}'({k_1}a)}}{{{H_n}'({k_1}a)}}\right)} } \right|,$ (2)

 ${f_\infty }^{ur}({{\text{π}}}) = \left| {\frac{2}{{\sqrt {{{\text{π}}} {k_1}a} }}\sum\limits_{n = 0}^\infty {{{( - 1)}^n}{\varepsilon _n}\left({b_n} + \frac{{{J_n}'({k_1}a)}}{{{H_n}'({k_1}a)}}\right)} } \right|{\text{。}}$ (3)

 图 3 柱壳的形态函数分解 Fig. 3 Shape function decomposition of cylindrical shells

 图 4 阻尼对纯弹性散射的影响 Fig. 4 Influence of damping on pure elastic scattering
1.2 钢材阻尼对相似性的影响

 图 5 阻尼对球壳和柱壳目标相似性的影响 Fig. 5 Influence of damping on target similarity

2 不同金属材料的阻尼对目标强度的影响

 图 6 不同阻尼对柱壳目标强度的影响随频率的变化 Fig. 6 The effect of different damping on the strength of cylinder shell with frequency

 图 7 各频率点处阻尼变化对目标强度影响的变化 Fig. 7 The effect of damping variation on target strength at different frequency points
3 结　语

1）计算阻尼对水中规则几何形体目标强度的影响以及考虑阻尼之后缩比模型的相似性，结果表明：钢材阻尼对目标强度的影响只在共振频率点处对共振峰有抑制作用，并且幅度都非常小可以忽略不计，对缩比模型的相似性没有影响，满足材料的声学相似。

2）金属材料的阻尼因子一般比较小且在大频率范围内不随频率变化而变化，本文取阻尼范围为0.000 1～0.01，计算了不同阻尼随着频率的变化对目标强度的影响，得到以下结论：金属材料阻尼对目标强度的影响都比较小，随着阻尼的增大而增大，钢材的阻尼因子对目标强度的影响可以忽略不计，钢材的缩比模型满足材料的声学性能相似。

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