冲击载荷作用下薄壁结构阻尼减振降噪技术研究

发布时间：2018-06-27 20:50

本文选题：薄壁结构 + 冲击载荷　；参考：《沈阳航空航天大学》2014年硕士论文

【摘要】：针对飞行器薄壁结构经常受到冲击载荷的作用而产生强烈的结构振动并辐射较大的噪声,严重损害工作人员听力、影响结构质量和工作效率问题,提出通过敷设约束阻尼的方式来解决这一问题。本文利用数值仿真的方法对冲击载荷作用下金属薄壁结构的振动和声辐射特性进行了研究,并通过对约束阻尼的各参数配置,总结出约束阻尼结构振动和声辐射特性的影响因素和变化规律。最后对全约束阻尼进行优化设计,实现了厚度的最优配置,减振降噪效果显著。本文采用耦合有限元和间接边界元的方法,研究了三方面的内容。其一,建立了薄壁板四边简支的有限元模型,在薄板中心点施加冲击载荷,改变冲击载荷的形式和大小,对结构进行瞬态位移响应计算和频域振动特性求解。对噪声辐射的声功率及和声场进行求解,研究载荷形式和大小对薄壁结构振动和噪声辐射的影响。其二,建立全敷设和部分敷设约束阻尼结构四边简支模型,在薄板中心点施加半周期正弦形冲击载荷。研究全敷设约束阻尼结构阻尼层厚度对振动和噪声辐射的影响,及部分敷设约束阻尼结构的不同敷设位置和面积对结构振动和噪声辐射的影响。其三,根据声辐射功率与结构表面振动速度之间的关系,选取振动速度的平方和作为目标函数,各层厚度和总质量分别作为设计变量和状态变量,对一块四角固定的矩形约束阻尼板进行优化仿真,并对优化前后的约束阻尼板进行振动和声学响应分析。本文对薄壁结构冲击载荷作用下结构振动和噪声辐射特性进行研究,应用数值仿真计算方法,研究了约束阻尼结构振动和声辐射特性的影响因素,编写了约束阻尼优化设计程序,总结了约束阻尼结构振动和声辐射特性的变化规律,实现了显著的减振降噪效果。计算结果和结论对阻尼设备的研发、工作效率的提高都有一定的参考价值。
[Abstract]:The thin-walled structure of aircraft is often subjected to the impact load and produces strong structural vibration and large noise, which seriously damages the staff's hearing, and affects the quality of the structure and the efficiency of the work. It is proposed to solve this problem by applying constrained damping. In this paper, the vibration and acoustic radiation characteristics of thin-walled metal structures under impact load are studied by numerical simulation, and the parameters of constrained damping are configured. The influence factors and variation rules of vibration and acoustic radiation characteristics of constrained damping structures are summarized. Finally, the optimum design of fully constrained damping is carried out, and the optimal configuration of thickness is realized, and the effect of vibration and noise reduction is remarkable. In this paper, the coupling finite element method and indirect boundary element method are used to study three aspects. Firstly, the finite element model of simply supported thin-walled plate is established. The impact load is applied at the center of thin plate, the form and magnitude of impact load are changed, the transient displacement response of the structure is calculated and the vibration characteristics in frequency domain are solved. The sound power and sound field of noise radiation are solved, and the effects of load form and magnitude on vibration and noise radiation of thin-walled structures are studied. Secondly, the four-side simply supported models of fully laid and partially laid damped structures are established, and the semi-periodic sinusoidal impact loads are applied at the center of the thin plate. The effect of damping layer thickness on vibration and noise radiation of fully damped damping structure and the effect of different location and area of partial constrained damping structure on vibration and noise radiation are studied. Thirdly, according to the relationship between acoustic radiation power and vibration velocity of structure surface, the square sum of vibration velocity is chosen as the objective function, and the thickness and total mass of each layer are taken as design variables and state variables, respectively. The optimization simulation of a rectangular constrained damping plate with fixed four corners is carried out, and the vibration and acoustic responses of the constrained damping plate before and after optimization are analyzed. In this paper, the vibration and noise radiation characteristics of thin-walled structures under impact load are studied. The factors influencing the vibration and acoustic radiation characteristics of constrained damping structures are studied by numerical simulation. The optimization design program of constrained damping is compiled, and the variation rules of vibration and acoustic radiation characteristics of constrained damping structures are summarized, and the remarkable effect of vibration and noise reduction is achieved. The calculation results and conclusions have some reference value for the research and development of damping equipment and the improvement of working efficiency.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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