Use of microprocessor acoustic emission systems during aircraft endurance testing

In this article, the results of endurance testing of aircraft using the acoustic-emission method (AE) are given. Measurement information was recorded by certified distributed and combined systems. A total of 62 loading blocks were performed; each included nonflight, take-off, and flight modes. Arrival of recorded AE signals was combined with the onset of the program cycle. Examples of the localization of AE signals were given from the zones under study with the development of fatigue fractures along the left and right sides of the aircraft. The results of comparative testing on an aircraft panel with a size of 1500 × 1800 mm were analyzed using distributed and combined AE systems.     

应用振动测试分析诊断XA6132铣床故障

为保证机床的机械运转状态达到规定振动指标,应对机床进行振动测定。通过频谱分析对振动信号进行分析、提取和判断,找出故障位置和产生的原因,给出解决办法,并根据机床运转状况制定维护措施。以XA6132铣床为对象进行实例分析,结果表明,理论分析与实测结果相吻合。     

采用结构光视觉检测技术进行断路器装配完整性的检测

结构光视觉测量技术作为新的检测技术已经成功应用于现代工业中,本文以结构光视觉传感器在电器器件检测的应用实例充分展示了应用结构光检测替代传统检测方法采解决检测存在误检和漏检的问题,体现了结构光检测技术的优越性.     

模态分析方法在汽车排气系统振动研究中的应用

汽车排气系统的振动和噪声对汽车舒适性和排气系统寿命都有很大影响。汽车排气系统为多自由度复杂系统,传统方法很难对其振动特性进行分析。为解决此问题,引入了模态分析方法,建立了汽车排气系统精细的有限元模型,对有限元模型进行频率范围在0～150Hz内的边界约束状态下的模态分析,获得其在150 Hz以内的各阶固有频率及其所对应的振型图,并根据结果对该排气系统进行振动特性分析。     

振动测试中传感器的选择和使用

振动会对机器和设备带来各种破坏,特别是会对人体造成严重的危害。正确合理地选择传感器对测试振动尤为重要。本文介绍了振动测试传感器的分类、选择、布置和使用中的注意事项。     

Failure mechanism-based reliability assessment framework: a case study in an automotive component

This paper presents a framework for failure mechanism-based reliability assessment, starting from collecting failed field samples. The framework includes failure analysis for identifying the failure mechanism and accelerated life tests (ALTs) for reproducing the failure mechanism. We consider that relevant information, such as warranty data and qualification test results, enables to be utilized in the framework. The proposed framework is validated by using it to identify the failure mechanism and estimate the lifetime of an automotive component under normal use conditions. The case study shows that the framework enables to quantitatively assess reliability based on the failure mechanism.

     

Laser welding defects detection in automotive industry based on radiation and spectroscopical measurements

Laser welding is a common technique in the automotive industry. For economic reasons, it is of great importance to detect the defects that can appear. The CO₂ penetration laser welding process is characterized by the formation of an electron-free plasma whose radiation can be measured to detect the defects. This paper presents two different approaches to defect detection. The first is based on the correlation between the power spectrum of a photodiode-generated signal and the defects. The second approach is based on the plasma electronic temperature, which is correlated to the presence of defects. Results obtained in an industrial facility under production conditions are presented.     

轻型客车白车身动态性能测试研究

设计了某轻型客车白车身试验悬挂系统,运用实验模态分析方法,测得了结构的频响函数,确定了系统的模态特征;并测得了车身质量,测试结果为修正其有限元动力学模型提供了重要依据,从而为实现整车轻量化设计和动态设计奠定了基础,也为大型复杂结构模态试验提供了参考。     

动应变测量系统在机械振动信号检测中的应用

利用电阻应变计开发的动应变测量系统,成功的实现了机械振动信号的动态检测.这里对动应变测量系统进行分析,并在实测中验证了该测量系统的功能.     

水轮机组低频振动检测技术研究

水电机组振动参数是监测水电机组运行稳定性的主要指标,本文提出了一种基于光纤传感的低频振动检测技术方法,较好地解决了因水电机组转速(频率约为1Hz)太低,传统惯性式低频振动传感器其输出信号信噪比低的固有缺陷,实验结果表明其方案是行之有效的.     

水轮发电机组振动的主要特征及测试与识别

通过对水轮发电机组振动机理的调查研究，提出了水轮发电机组振动信号的一般特征，并由振动特征判别振动原因。     

铸造起重机调速时振动分析

1 铸造起重机工作概况及要求 铸造起重机是冶金厂主要起吊设备,用于炼钢车间吊运满载的钢水包及铁水罐,它在多台种设备混杂的环境中频繁工作。随着现代企业炼钢工艺的要求及生产率的提高,一般都要求增加调速功能,由电气控制,将各机构分别设置快、慢挡进行调速,以确定各个工况要求。由于铸造起重机吊运的是熔融金属,它的平稳运行,安全可靠尤为重要。     

微光探测装置自成暗室设计开发

针对现有微光检测系统体积大、避光效果差等不足,对微光探测装置进行全新设计。采用反应杯与光探测头自成暗室,减少暗室进出机构,提高避光效果;采用斩波法扣除本底计数,从而消除背景光引起的测量误差。性能测试结果显示:该微光探测装置的光子本底计数小于等于200光子/s,测光上限平均值达到1.1×107光子/s,变异系数(CV)小于等于3%,达到目前现有的微光检测系统的技术指标要求,可用于化学发光免疫分析仪等需要进行微光信号检测的精密仪器开发,对基于微光探测技术的仪器行业的发展具有重要意义。     

适用于光照不均匀图像的边缘检测算法

首先利用图像梯度方向特征改进Canny算法,使之更适合连续边缘的检测。然后将其与基于侧抑制原理的图像增强算法结合,设计了一种新的适用于噪声背景下光照不均匀图像的边缘检测算法。算法实验结果表明该边缘检测算法能有效提取光照不均匀图像中的连续边缘。     

制氢车间螺杆压缩机振动故障分析与处理

针对制氢车间LG60／1．0型螺杆压缩杌组运行过程中振动幅值高居不下的状况，分析了发生的原因，提出了解决的措施，取得了良好效果，对于类似螺杆压缩机的日常维护和检修有一定借鉴意义。     

超声磨削系统中圆锥形变幅杆的数值模拟及性能测试

由变幅杆大端直径、放大倍数、面积系数等已知条件,按照变幅杆设计理论对超声振动系统中的变幅杆进行设计;确定出其理论共振长度、小端直径、位移节点、放大系数、形状因数等参数。利用ANSYS进行建模,并对变幅杆振动性能进行数值模拟分析以确定其合理性。最后对该变幅杆振动性能进行试验测试分析。     

基于高阶多振型频率的磁瓦缺陷音频检测方法

传统音频检测技术存在特征量单调、被测工件需为规则形状、缺陷类别分辨能力不强等局限性,针对磁瓦检测过程中的需求,本文在建立无约束自由振动物体任意阶数模态向量的数学模型基础上,给出了工件各类裂纹缺陷与高阶振型频率间的特性关系,提出一种运用高阶多振型频率及相邻振型频率差为特征量识别磁瓦中常见的贯穿弧顶轴向短裂纹、贯穿弧底切向短裂纹、内弧面切向裂纹及内、外弧面轴向裂纹等四类缺陷的新方法。运用有限元数值仿真法和3种型号磁瓦的音频实验方法验证其可行性和有效性,结果表明:基于高阶振型频率及相邻振型频率差组合的音频检测方法,能有效检测并分辨磁瓦多种缺陷类型。     

曲轴组件动平衡检测系统中振动台设计

振动台是检测曲轴组件动平衡系统中很重要的部件，在此提出了一种振动台设计方法，建立了振动台分析模型，并根据振动理论，推导出了计算振动台固有频率的公式和方法，对研究动平衡及其相关设计具有重要意义。     

Blind source separation for classification and detection of flaws in impact-echo testing

This paper presents a technique for defect detection and material classification based on blind source separation by independent component analysis (ICA) for application in impact-echo testing. The transfer functions between the impact point and the defects in the material are modelled as “sources” for blind source separation. The sensors located on the material surface measure a convolutive mixture of the contribution of each of the defects. From spectral analysis the dominant resonance frequencies, varying from homogeneous to defective material, are selected. These frequencies are processed by instantaneous ICA in order to obtain more information about the defects using bootstrap resampling to analyse the stability of the solution. Results show that source estimates fit well with the theoretical response of the material. In addition, it has been found that the number of defects can be estimated by ICA in simulations and experiments with various defective parallelepiped-shape materials of aluminium alloy series 2000.