金属与非金属粘接质量的声阵列检测方法

目的　研究金属与非金属质量检测的新方法 .方法　通过对粘接结构施加微力、阵列传声器检测、对信号进行处理识别 ,从而完成粘接结构力学性能的无损预报 .结果和结论　提出了一种微声激励、声阵列检测的新的检测方法和总体设计方案 ,该方法可以解决超声检测耦合难、检测速度低、误判漏判率高的问题  

声激励共振法测量微机械材料的杨氏模量

微机械材料的杨氏模量测量是随着微机械构件的产生而提出的一项新技术。文章综述了已有的测量微机械材料杨氏模量的方法。提出了用声激励共振法来测量微机械材料的杨氏模量。这种方法具有测试装置简单、测量容易、精度高等特点。  

客车异常振动噪声的分析和控制

某款轻型客车样车在90 km/h左右速度行驶时，车厢地板出现剧烈振动并伴随共鸣噪声，严重影响汽车NVH性能。通过试验手段，在五档加速工况对振动频率进行时间跟踪，找到可能的激励源。从三维频谱图识别出车内主要振动和噪声频率与传动轴的1阶和2阶转动频率相同。对此进行加强传动轴支架，支架加橡胶垫和改换悬置为进口悬置的改进。由此可使整车振动噪声水平大幅度降低。  

Nonlinear radial oscillations of micro-bubbles in a compressible UCM medium

The nonlinear oscillations of acoustically forced spherical gas bubbles in an upper-convected Maxwell (UCM) compressible fluid are investigated. The nonlinear viscoelastic model used is suitable for large-amplitude excitation of bubbles that cannot be captured by linear models. The effects of acoustic excitation are studied for compressible nonlinear viscoelastic media, which increases the complexity and nonlinearity of the behavior. The Keller–Miksis equation is used to model the dynamics of a single bubble. The constitutive equations of compressible UCM are used for viscoelastic media. These governing equations are non-dimensionalized and coupled to determine the bubble dynamic behavior. The set of derived non-dimensionalized integro-differential equations developed are numerically solved simultaneously using the fourth-order Runge–Kutta method featured by the automatic variable time step-size module. The combined effects of compressibility and viscoelasticity of the fluid on bubble radius are investigated. The results show that the combination of compressibility and nonlinear viscoelasticity for bubble radial oscillations makes forced bubble dynamics more applicable for human needs, especially for large deformations in highly non-Newtonian fluids like industrial polymers or even tissue-like media. It can be seen that compressibility controls the oscillations at higher forcing amplitudes. The relevance and importance of these bubble dynamics to biomedical ultrasound applications and light emissions by sonoluminescence and other industries are evident.  

Remote Optical Non-Destructive Inspection Technique for Metal and Composite Structures

This paper presents a laser based non-destructive inspection technique which is purely non-contact. An acoustic device is used to remotely excite the material under inspection while a scanning laser vibrometer is employed to measure the resulting vibrations. The test materials, mostly aluminum or composite aircraft structures, have been successfully inspected from a standoff distance of at least a meter. The NDI system clearly shows the defect locations overlaid on the images of the test objects for ease of the end user. Metal and composite delamination and subsurface corrosion in aluminum structures are among the defects that were detected.