结构阻尼传播衰减测试方法研究

【作者】 张政；

【导师】 盛美萍；

【作者基本信息】 西北工业大学 ， 环境工程， 2005， 硕士

【摘要】 结构阻尼是工程材科和结构的重要特征参数之一,结构与材料的阻尼特性研究一直是振动与噪声控制的重要内容,而合适的阻尼测试方法和较高的测试精度是合理评价阻尼特性的根本依据。 本论文主要包含三部分内容:①结构振动特性分析;②传播衰减法测结构阻尼的原理与实验验证;③新型宽带激振器的研制与应用。 本文首先分析了无限结构和有限结构的振动特性,包括无限梁、半无限梁、无限平板、周边简支板等,在此基础上对比了无限结构和有限结构的振动响应并分析其类比特性。进而分析了圆柱壳体的频率响应特性,研究表明:在相当宽的频率范围内,圆柱壳体振动特性与梁板结构振动特性相似。 在上述研究基础上,本文根据弹性体振动理论,研究了利用传播衰减法测量结构阻尼的方法,推导了无限和有限结构阻尼测试的计算公式,并给出了此方法在有限结构上的测试范围。进而,论文研究了圆柱壳体与梁板结构的阻尼类比性关系,利用类比关系可进一步将传播衰减法应用于壳体阻尼预测。 宽带测试是结构阻尼测试的难题,为了适应实际工程中宽带测试的需要,本文研制了一种集电动激振和压电激振原理于一体的新型宽频带激振器。本文提出了新型宽带激振器的设计原理,并完成了原理样机的研制。通过与传统的电动激振器和压电激振器的对比实验,验证了其宽频带特性。 最后,利用本文研究的测量结构阻尼的传播衰减法、采用本文研制的宽频带动力激振器,开展了传播衰减法的阻尼测试实验。首先以半无限长梁为实验对象,分别采用瞬态法、传播衰减法测量其阻尼,并与理论计算结果对比,实验证明本文提出的传播衰减法是可行的。为验证该方法的正确性,本文进一步开展了梁、板实验,结果表明:本文提出的传播衰减法在有限结构上进行测试的边界条件是正确的。更多还原

【Abstract】 Structural damping is an important characteristic of engineering materials and structures, and it always is one of the important research content in vibration and noise control. Meanwhile proper measurement method and better measurement precision are the essential foundations of the reasonable evaluation of damping features.This thesis mainly includes the following three aspects: 1. analysis of the vibration characteristics of structures; 2. research on measurement of structural damping using Propagation-Attenuation Method (PAM); 3. design of a new type wide-frequency actuator .The vibration characteristics of infinite and finite structures are analyzed, and the comparison between the response characteristics of them is obtained, then the vibration characteristics of infinite cylindrical shell are analyzed. The research shows that the vibration characteristics of cylindrical shell and beam or plate are similar.In this thesis, the damping measurement using PAM is developed, and the calculation formula of damping in infinite and finite structures is obtained, and the measurement area using PAM in finite structures is carried out. According to the damping analogy between cylindrical shell and beam or plate, PAM can be applied to damping forecast of shell.Wide-frequency stimulation is difficult in damping test experiments. A prototype of new type wide-frequency actuator using dynamoelectric and piezoelectric actuations is developed for the need of practical engineering. The wide-frequency characteristic is validated according to the comparison of traditional actuators.At last, a damping test experiment is carried out by using PAM and new type actuator. The result shows that the boundary conditions in finite structures using PAM is reasonable.更多还原