大阻尼结构物理参数的测定

阻尼技术在减振降噪方面的应用已在近几十年内得到了飞跃的发展。但迄今为止国际上尚无统一标准方法以确定粘弹性材料及其结构的损耗因子和弹性模量等物理参数。虽然目前已有多种阻尼测量的手段；但其中的大多数仅适用于测量材料的物理参数。而频率响应法和自由衰减法等常用于测量复合结构物理参数的方法均不适用于大阻尼的结构。本文提出一种以悬臂梁为基础，利用微计算机及其接口技术，研究沿悬臂梁自由衰减的前进波，并运用线性近似理论得出复合结构物理参数的方法。实验证明该方法具有一定的精度和可重复性，是一种测量大阻尼结构物理参数的有效手段。它弥补了其它一些方法的不足，使测量阻尼的手段更趋完善。

The Measurements of the Physical Parameters of High Damping Structures

The application of damping technology in vibration damping and noise reduction has being developed by leaps and bounds in decades.There has not been yet a normal method to determine the physical parameters of viscoelastic materials and their structures, such as loss factor and modulus of elasticity,etc.Although there are many methods to measure the physical parameters,most of them are only applicable for materials.The resonance measurements and time-decay-rate measurements,the ordinary manners for measuring the structure damping,are not suitable for high damping structures.In this paper a new thchnique is put forward to determine the physical parameters of high damping structures,which is by aid of a microcomputer and its interfaces to search the free decay waves along the cantilever and on the basis of theory of linear approximation to obtain the physical parameters of structures. The sources of varies errors are discussed as well.The technique proposed is particularly effective on high damping structures.