船舶结构振动传递规律的工程预报及抑制

发布时间：2019-05-23 17:14

【摘要】：近年来，随着船舶对动力和电力需求的提高，轮机设备规模和数量不断增大，结构声源强度也随之增强，如何降低船舶舱室振动和噪声，抑制结构声能能量的传递，提高船员及乘客的居住舒适性的问题得到了广泛的关注，已成为造船界的焦点问题之一。过强的振动不仅会导致船舶结构的疲劳破坏，影响船内各种仪器、设备的正常使用，造成安全隐患，由其辐射出的噪声更是会对船员和乘客造成巨大干扰。本文以波动分析法为理论依据，采用数值计算和实验验证相结合的方法研究了转角结构对结构声抑制作用，并在此基础上开展结构声在船舶舱室中传递的预报及其在双层壳船舶结构中传递衰减规律的研究。此外，还提出了阻振质量和阻尼相结合的方法，提出了一经济有效的阻波方案。本文的研究工作有如下几个方面： (1)利用波分析法推导了有限长板简单转角和多转角模型的质点振动速度场及振动能量密度分布情况，以及加筋情况下的结构声传递规律。提出将加筋板简化为正交各项异性板的简化方法。 (2)研究典型船舶结构加筋板中的结构声传递规律，应用波分析法推导了加筋多转角结构的位移和振动能量传递表达式，并通过数值计算研究了各种参数对结构声传递的影响。从数值计算结果可见，板厚和转角级数为影响振动衰减的主要因素，板长、转角形式、板厚比和加强筋为次要因素，转角角度在快速预报中可以忽略不计。在此基础上，，本文提出一个典型船舶结构中振动衰减的快速预报公式，并通过船舶舱段的缩尺模型实验对其进行验证。 (3)结合理论分析及数值计算研究了双层壳振动能量传递特性，并提出将声桥简化为梁的方法。该方法可以减少自由度，提高计算效率。此外，还利用数值计算分析了声桥等效刚度及阻尼层对双层壳结构结构声传递规律的影响。 (4)基于波动法建立了船舶舱段结构的振动微分方程，引入无量纲系数并利用等效损失因子和杨氏模量导出了阻尼与阻振质量共同作用下结构中振动弯曲入射波的能量透射和反射效率，以及质点的振动位移场及能量密度的分布情况。在此基础上，利用数值计算对各种布置阻振质量和阻尼的降振方案进行了研究，并做了综合全面的比较。本论文的研究不仅全面综合的分析了结构声在船舶结构中的传递规律，提出了适用于工程的简化快速预报公式，而且还提出了阻抑结构声传递的优化方法。由此得到的结果可为船舶结构的优化声学设计提供理论依据，并为为船舶减振降噪提供新措施。
[Abstract]:In recent years, with the increase of ship's demand for power and power, the scale and quantity of marine turbine equipment are increasing, and the intensity of structural sound source is also enhanced. how to reduce the vibration and noise of ship cabin and restrain the transmission of structural acoustic energy. The problem of improving the living comfort of crew and passengers has received extensive attention and has become one of the focus issues in the shipping industry. Excessive vibration will not only lead to fatigue damage of ship structure, affect the normal use of all kinds of instruments and equipment in the ship, and cause hidden dangers of safety, and the noise emitted by it will cause great interference to the crew and passengers. In this paper, based on the theory of wave analysis, the acoustic suppression effect of rotation angle structure on structure is studied by means of numerical calculation and experimental verification. On this basis, the prediction of structural sound transmission in ship cabin and its transmission attenuation law in double shell ship structure are studied. In addition, a method of combining vibration resistance quality with damping is proposed, and an economical and effective wave resistance scheme is proposed. The research work of this paper is as follows: (1) the particle vibration velocity field and vibration energy density distribution of simple and multi-angle models of finite length plates are derived by using wave analysis method. And the sound transmission law of the structure under the condition of reinforcement. A simplified method for simplifying stiffened plates to orthotropic plates is proposed. (2) the acoustic transmission law of reinforced plates in typical ship structures is studied, and the expressions of displacement and vibration energy transfer of reinforced multi-angle structures are derived by using wave analysis method. The effects of various parameters on the sound transmission of the structure are studied by numerical calculation. From the numerical results, it can be seen that the plate thickness and rotation angle series are the main factors affecting vibration attenuation, and the plate length, rotation angle form, plate thickness ratio and reinforcement are the secondary factors, and the rotation angle can be ignored in the rapid prediction. On this basis, a fast prediction formula for vibration attenuation in typical ship structures is proposed and verified by the scale model experiment of ship sections. (3) combined with theoretical analysis and numerical calculation, the vibration energy transfer characteristics of double-layer shell are studied, and the method of simplifying sound bridge to beam is put forward. This method can reduce the degree of freedom and improve the calculation efficiency. In addition, the effects of equivalent stiffness of acoustic bridge and damping layer on acoustic transmission of double-layer shell structure are analyzed by numerical calculation. (4) based on the volatility method, the differential equation of vibration of ship cabin structure is established. The energy transmission and reflection efficiency of vibration bending incident wave in structure under the action of damping and vibration resistance mass are derived by introducing dimensionless coefficient and equivalent loss factor and Young's modulus. And the distribution of vibration displacement field and energy density of particles. On this basis, various damping schemes with damping mass and damping are studied by numerical calculation, and a comprehensive comparison is made. In this paper, not only the transmission law of structural sound in ship structure is analyzed comprehensively and comprehensively, a simplified and rapid prediction formula suitable for engineering is put forward, but also the optimization method of restraining structural sound transmission is put forward. The obtained results can provide a theoretical basis for the optimal acoustic design of ship structures and provide new measures for ship vibration and noise reduction.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661.44

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