多层包扎高压氢气储罐的声发射检测技术研究

1　前言天津石化公司化工厂ＰＸ生产装置有 1 0台多层包扎式氢气储罐 ,这类储罐属Ⅲ类压力容器。根据劳动部《压力容器安全技术监察规程》的要求 ,这类储罐使用到检验周期必须实施定期检验 ,但由于多层包扎储罐的结构特点 ,一般常规无损检测方法无法对其进行全面检验 ,导致企业压力容器管理及安全生产存在隐患。声发射技术由于其实用性强 ,检测灵敏度高 ,在很多领域得到广泛应用。目前 ,在金属压力容器检验及安全评定中 ,声发射已是一种重要的无损检测方法 ,尤其是在单层金属压力容器的检验中已成功应用 ,并有相关的检测标准。通过解剖一台…     

多层层板压力容器规程VdTUV规范 359 1971

1.适用范围 1.1 本规程适用于多层包扎的压力容器。该结构容器是指在内筒外的简体壁厚是由多层层板构成。本规程包括材料、制造、计算和检验方面内容。 1.2 本规程适用的多层包扎式压力容器,其外径与内径之比值最大为1.5,同时它们在大     

储罐内置式声发射多传感器投放装置创新设计

储罐底板腐蚀声发射在线检测技术目前被广泛使用,但对于大型储罐,会存在检测盲区,内外部相结合的声发射在线检测技术是解决这一问题的有效方法。为此,设计储罐内置式声发射多传感器投放装置,该装置可以携带多枚声发射传感器,并精准投放到大型储罐内部指定位置,通过内部传感器与外部传感器联合监测,实现大型在用储罐底板腐蚀内外部结合的全域检测。     

环形腔全光纤F-P干涉仪的声发射检测实验研究

提出了一种新型结构的用于声发射检测的全光纤F-P干涉仪。选用2×2光纤耦合器，将耦合器的一个入射端与一个出射端焊接相连，以耦合器代替传统的反射腔面，构成光纤环形传输腔，腔体贴附或埋入待测固体中检测声发射信号。通过理论推导和计算机仿真，确定了此结构光纤传感器的检测特性。实验以大理石板作为待测介质，对利用信号发生器驱动PZT（压电陶瓷）作为已知超声源在大理石板中产生的连续型声发射信号，及冲击波作用下大理石板中产生的突发型声发射信号进行了检测，并利用Fourier变换，得到了声发射信号的特征频率。实验结果表明，此种结构传感器能够检测材料结构中促使光纤轴向伸缩长度的量级为10-8m的声发射信号并识别其特征频率，该结构光纤传感器无需光程的匹配，适用于大尺度构件的监测，为材料结构健康检测与监控提供了一种新的方法。     

钛复合钢板多层包扎容器腐蚀泄漏后的检测与评定

本文论述了内筒为复合钛板的多层包扎式压力容器因钛层被冲蚀形成腐蚀空洞并造成腐蚀穿孔后如何进行无损检测和安全评定的问题。着重介绍了针对多层筒壁内腐蚀空洞的无损检测方法以及钛层下腐蚀缺陷的无损检测方法的试验研究。在试验研究的基础上确定了可行的检测方案。同时论述了腐蚀空洞类缺陷的安全评定方法。这种非常规的检测与评定方法对众多的在用多层包扎并有防腐衬里的容器有可以借鉴的共性。     

机械零件的声发射检测技术

主要从声发射机理、声发射传感器的研究和多传感器检测技术三个方面介绍了机械零件声发射检测技术的特点、研究现状和发展趋势。     

基于小波变换及互相关的声发射源定位研究

采用小波互换和互相关技术研究声发射信号的时间延迟,通过时差定位法对声发射源进行定位。首先通过Daubechies8小波对声发射信号进行5层分解,提取能量最大的那一分解层信号,然后利用互相关技术计算出该层信号到达各个传感器所需的时差,最后利用时差定位法对声发射源进行定位。结果表明,定位平均误差都在4mm以内,借助该定位方法,声发射源的定位精度得到明显提高。     

泄漏声发射传感器性能检测技术研究

提出了利用压电晶体逆压电效应作为标准声源的声发射传感器的性能检测方法。在此基础上,设计实现了基于比较检测法的泄漏声发射传感器性能检测系统,并应用到泄漏声发射传感器辐照后的性能检测中。检测结果和传感器使用效果表明,该方法用于声发射传感器性能检测是可行的。     

较小样本动态声发射信号多元统计分析技术

利用多传感信息集成系统,以两组平均年龄对应的受试对象往复运动过程中获取的动态声发射信号和角度信号为对象,研究了适用于较小样本的动态声发射信号多元统计分析技术.通过同步记录的角度信号,将往复运动分解为若干个独立运动周期和运动过程;利用累计概率分布,选取具备较显著差异的特征;结合多元统计技术,减小数据量,建立动态声发射信号的可视化模型,证实了使用较小样本声发射信号实现膝盖骨关节诊断的可行性.     

基于声发射检测的能量释放率预测多向复合材料层合板的分层机理

针对复合材料压力容器的损伤在线监测问题，利用应变能释放率对双悬臂梁标准试验过程中的复合材料分层损伤机理进行了研究。为此，制备了铺设角度分别为0°,30°,45°和60°的不同界面纤维取向24层玻璃/环氧复合材料层合板，利用声发射技术检测多向复合材料层合板的损伤机理(结合显微可视化技术),证实了应变能释放率可作为预测复合材料分层损伤的判据；发现声发射参量可以较早地预测层合板的损伤。由此，提出了一种通过声发射参数代替原本测量裂纹长度的计算方法来预测分层损伤的方法。结果表明，该方法与传统测量计算方法相比，可以更早地监测层合板的损伤。     

1000 m3液化气球罐的声发射检测

采用声发射检测技术对10 0 0m3液化气球罐的上半球罐进行了声发射检测,并将声发射检测结果与常规磁粉探伤结果进行了比较,发现利用声发射方法检测出需要复查的区域与磁粉探伤结果具有较好的符合性。对今后关键压力容器的不开罐定期检验具有指导意义。     

新型高压容器多层整体包扎的箍紧力与包扎方式

新型高压容器多怪整体包扎制造中,针外层卷曲钢板直接拉紧缠绕于内筒体上,所需拉紧合力远小于采用多根钢丝绳把卷曲外层钢板内筒体的箍紧合力,且层析间接触较均匀,是高压容器制造优选方法。     

承压类特种设备断层解剖检验及应用

承压类特种设备检验时，有时应用现有无损检测手段不能发现危险的缺陷。文中首次提出断层解剖检验。断层解剖检验将样品断层解剖，并逐层检验样品的缺陷。断层解剖检验可以发现缺陷在不同断面上的形态、尺寸、位置、特点、成因、危害以及多个缺陷相互关系。断层解剖检验发现了封头上被认为是夹层的缺陷是HB、HIC和SSCC。断层解剖检验是工业CT等三维成像检验技术的基础。     

压力容器用钢氢致开裂的声发射试验研究

氢致开裂是在役压力容器一种常见的失效形式。声发射技术是监测动态破坏过程的有效手段。为了研究压力容器用钢氢致开裂过程的声发射特征,对电解充氢过程中的20R钢进行了监测。试验结果表明,碳钢表面电解充氢并腐蚀的过程和内部氢致裂纹的产生均会对材料的声发射活动产生影响。氢致裂纹的发展过程可分为孕育期和扩展期两个阶段,随着裂纹的生长,高幅声发射信号的数量明显增多。试验结果为压力容器现场检验提供了参考。     

Diagnostics of critical points of the friction coefficient of a multilayer nanomodified antifriction coating by an acoustic emission technique

The dynamics of the changing parameter of the acoustic emission (AE) in the course of tests of a multilayer nanomodified antifriction coating are considered. The results of investigating the shape and the spectra of AE pulses in different regions of the experimental curve of the dependence of the friction coefficient on the test time are reported. A method is proposed for establishing the transition points from the steady-state stage to the failure and friction-without-coating stages according to the intensity of the restored AE event stream, the spectral distribution, and the amplitude of the concurrent acoustic emission in the ultrasonic-frequency range.     

Real‐Time Monitoring of Tool Fracture in Turning Using Sensor Fusion

The sensor fusion method using both an acoustic emission (AE) sensor and a built-in force sensor is introduced for on-line tool condition monitoring during turning. The cutting force was measured by a built-in piezoelectric force sensor, which was inserted in the tool turret housing of an NC lathe. FEM analysis was carried out to locate the most sensitive position for the sensor. A burst of AE signal was used as a triggering signal to inspect the cutting force. A significant drop in cutting force indicated tool breakage. The algorithm was implemented in a DSP board and the monitoring system was installed on a CNC lathe in an FMS line for in-process tool-breakage detection. The proposed system showed an excellent monitoring capability.     

An impact source localization technique for a nuclear power plant by using sensors of different types

In a nuclear power plant, a loose part monitoring system (LPMS) provides information on the location and the mass of a loosened or detached metal impacted onto the inner surface of the primary pressure boundary. Typically, accelerometers are mounted on the surface of a reactor vessel to localize the impact location caused by the impact of metallic substances on the reactor system. However, in some cases, the number of accelerometers is not sufficient to estimate the impact location precisely. In such a case, one of useful methods is to utilize other types of sensor that can measure the vibration of the reactor structure. For example, acoustic emission (AE) sensors are installed on the reactor structure to detect leakage or cracks on the primary pressure boundary. However, accelerometers and AE sensors have a different frequency range. The frequency of interest of AE sensors is higher than that of accelerometers. In this paper, we propose a method of impact source localization by using both accelerometer signals and AE signals, simultaneously. The main concept of impact location estimation is based on the arrival time difference of the impact stress wave between different sensor locations. However, it is difficult to find the arrival time difference between sensors, because the primary frequency ranges of accelerometers and AE sensors are different. To overcome the problem, we used phase delays of an envelope of impact signals. This is because the impact signals from the accelerometer and the AE sensor are similar in the whole shape (envelope). To verify the proposed method, we have performed experiments for a reactor mock-up model and a real nuclear power plant. The experimental results demonstrate that we can enhance the reliability and precision of the impact source localization. Therefore, if the proposed method is applied to a nuclear power plant, we can obtain the effect of additional installed sensors.     

铁路货车轮对轴颈轴承内圈松动故障检测

采用声发射和振动加速度传感器对铁路货车轮对轴承内圈松动故障进行检测,并用小波包分析方法提取故障信号的能量特征向量,通过对内圈不松动和松动两种情况下能量分布的比较,提取高频带内能量与总能量之比作为特征参数,可有效诊断内圈松动故障。     

Misalignment inspection of multilayer PCBs with an automated X-ray machine vision system

In recent times, multilayer printed circuit boards (PCBs) have been extensively applied in the electronics industry owing to their high capacities for complex and densely packed circuit layouts arranged in a limited space. The inspection of fabricated multilayer PCBs is thus important in order to ensure quality control and improve the fabrication process. In this paper, an automated X-ray machine vision system was developed exclusively for the inspection of the layer-to-layer misalignment of laminated multilayer PCBs. Based on a mechatronics system and X-ray image processing techniques, an automated misalignment inspection process was established. Experiments meant to inspect three critical layer-to-layer misalignment modes, expansion, contraction, and offset, found within ten-layer PCB samples, were conducted to test the feasibility of the developed machine inspection system. The experimental results show that the developed X-ray machine vision system, combined with the automated misalignment inspection process, was able to undertake misalignment inspection of certain multilayer PCBs.     

基于VBA的法兰带压密封夹具设计

针对压力容器和管道法兰带压密封夹具设计中存在的难点，以弯曲梁理论为基础，建立了法兰夹具力学模型，推导出了更接近实际的夹具强度计算公式。依据泄漏介质温度、压力、法兰外周长、法兰副的连接间隙、连接螺栓的个数、夹具材料的许用应力及夹具强度计算公式，采用VBA编制了夹具设计智能化软件。应用实例证明了该软件的实用性和易用性，初步实现了压力容器和管道法兰夹具设计的智能化。