铝蜂窝胶接缺陷的红外热波无损检测

蒙皮与蜂窝之间的脱粘缺陷使铝蜂窝夹心复合板的强度大大降低，严重影响金属蜂窝胶接产品的应用，必须对其进行严格的无损检测。用红外热波技术对铝蜂窝夹层胶接结构进行检测，结果表明，该技术可对试件夹层胶接质量和蜂窝结构作快速有效直观的检测。     

铝蜂窝夹芯结构的数字成像检测研究

蜂窝夹芯结构常见缺陷有蒙皮与蜂窝芯脱粘、蜂窝芯变形、蜂窝芯节点开裂和蜂窝积水等,目前单一的无损检测方法还不能有效地解决蜂窝夹芯结构中的各种缺陷检测问题。针对铝蜂窝夹芯结构,首先制作了6种典型人工缺陷,利用射线DR(Digital Radiography)和计算机射线照相(Computed Radiography,CR)技术对夹杂、蜂窝芯变形、蜂窝芯格断裂、富胶等缺陷进行了数字射线成像检测,得到了高质量的缺陷数字检测图像,并进行了对比分析。针对蜂窝积水检测问题,采用射线DR技术进行了数字成像检测研究,表明积水量大小会影响图像灰度。对含有人工脱粘缺陷的铝蜂窝夹芯结构件,采用脉冲反射法对其粘接质量进行了超声C扫描成像检测研究,通过底波幅值成像得到了脱粘缺陷的超声C扫描数字图像。结果表明:数字射线成像和超声C扫描成像结合为蜂窝夹芯结构提供了一种数字化的无损检测方法。     

玻璃钢蒙皮纸蜂窝材料的无损检测

玻璃钢纸蜂窝材料的蒙皮分层缺陷以及蒙皮与蜂窝之间的脱粘缺陷将直接影响蜂窝结构的机械性能和工作性能,必须对其进行无损检测。利用红外热成像系统及超声C扫描系统分别对玻璃钢纸蜂窝材料的蒙皮质量及胶结质量进行检测,两种方法各有忧劣：红外热成像系统检测过程时间短,效率高,分层缺陷及脱粘缺陷均能检测到,而超声C扫描系统可检测出所有脱粘缺陷,且纸蜂窝结构清晰,但只检测出了部分蒙皮分层缺陷。     

铝蜂窝内腐蚀缺陷的脉冲涡流检测传感器参数优化

铝蜂窝内腐蚀缺陷的检测一直是无损检测领域的一个难点和热点。脉冲涡流检测技术对腐蚀缺陷十分敏感,采用该技术对铝蜂窝内腐蚀缺陷进行检测,设计了一种双激励的U型探头,并用TMR芯片接收信号。通过大量试验对U型探头模型、激励线圈匝数、TMR接收位置、激励频率和占空比进行了优化选择,确定了U型探头检测铝蜂窝内腐蚀缺陷的最优参数,使U型探头检测灵敏度达到最高。     

焊接结构的无损检测技术

各种焊接技术越来越广泛地应用于石油行业、核工业、航空航天、机械制造等众多领域,严格控制各焊接结构的生产质量是保障产品整体完整性、安全性的关键因素。本文详细论述了焊接结构中的各种缺陷类型,常用无损检测方法的技术特点及其对焊接结构典型缺陷的检测适用性。     

冲击回波法在混凝土无损检测中的应用

冲击回波法是一种有效的检测混凝土结构的无损检测方法，通过试验验证，它不仅可准确测量混凝土结构的厚度，也可确定混凝土结构内部的各种缺陷，如表面开口裂缝、空洞及蜂窝等。实用性较强，检测精度较高。成像软件的使用使缺陷的辨别更加直观、简便。     

空气耦合超声技术在航空航天复合材料无损检测中的应用

制备预埋人工缺陷的蜂窝夹芯复合材料、模压复合材料和陶瓷基复合材料试样,利用自主研制的内置专用信号处理单元的空气耦合超声无损检测系统进行试验,实现GFRP蒙皮Nomex蜂窝夹芯复合材料模拟脱粘缺陷检测、模压复合材料模拟内部分层缺陷检测以及C/SiC复合材料模拟内部分层缺陷检测。试验结果表明,空气耦合超声无损检测技术可应用于蜂窝夹芯复合材料、模压复合材料以及陶瓷基复合材料构件的非接触无损检测,在航空航天工程领域应用前景广阔。     

飞机铝蜂窝复合材料的典型缺陷检测

为有效检出飞机铝蜂窝复合材料的缺陷位置及缺陷大小,评估缺陷损伤程度,运用激光错位散斑检测方法对有无缺陷及缺陷位置进行了检测,并采用声阻检测方法对缺陷大小进行了评估。试验结果表明,激光错位散斑检测法能够快速定位飞机铝蜂窝复合材料缺陷的位置,但检测精度不高;声阻检测法能够对缺陷位置进行精确检测。两种检测方法的结合使用,提高了检测结果的可靠性和准确性,为进一步开展飞机铝蜂窝复合材料缺陷损伤检测及评估奠定了基础。     

基于神经网络的射线照相技术在焊接缺陷自动化检测中的应用

射线照相技术作为一种无损检测方法被广泛应用于研究和分析焊接不连续性。利用多层感知器MPC(multilayer perceptron)和人工神经网络ANN(artificial neural network),通过检测放射影像的边缘实现焊接缺陷的自动控制和检测。焊接缺陷的自动检测主要包括数据库的准备、MPC培训与编程、图像过滤与分割和轮廓的检测四个阶段。利用上述方法对输气管道用管缺陷进行案例分析,提出了一种更加有效的边缘检测质量评价标准,并归纳总结焊接缺陷检测的可视化方法步骤。     

超声相控阵技术检测蜂窝复合材料案例

随着蜂窝复合材料在航空航天领域的广泛应用,其无损检测的要求也越来越高。常规超声检测技术不仅速度慢而且分析困难。超声相控阵技术采用电子扫查,检测速度大大提升,再配合C扫描视图,可以使缺陷的分析变得简单。文章介绍了采用超声相控阵技术检测碳纤维蒙皮铝蜂窝工件、带涂层以及不带涂层的碳纤维蒙皮纸蜂窝工件的三个检测案例。从检测结果．-j-~得出,超声相控阵技术可以有效检测蜂窝复合材料的内部脱粘缺陷,具有很好的应用价值。     

激光电子剪切散斑干涉成像技术在复合材料检测中的应用

介绍了研制的激光电子剪切散斑干涉成像系统的原理及结构组成,对散斑图像进行了图像处理分析.用该系统检测玻璃纤维蜂窝结构件的模拟脱粘缺陷,缺陷散斑图像清晰可辨.试验证明,该系统可成功用于复合材料结构和蜂窝夹层结构的无损检测.     

蜂窝夹层结构胶接面树脂堆积的红外热像检测

为了研究树脂堆积的红外热像检测问题,文章进行了一维模型建模分析、蜂窝夹层结构样件试验验证和解剖分析。研究发现树脂堆积区域在脉冲加热后的原始热图中表现为"暗区"或"暗斑",并且这些区域的表面温度低于正常胶层厚度区域的表面温度,得出了树脂堆积可以在红外热像检测中被检出的结论。通常树脂堆积不是一种缺陷,但是对蜂窝夹层结构胶接面树脂堆积进行检测却具有重要的现实意义。判断树脂堆积区域的位置、形状和面积,将有助于改进生产工艺。对这些区域进行识别、记录和存档,可以为原位检测蜂窝积水问题提供评定的依据。     

Near-field microwave identification and quantitative evaluation of liquid ingress in honeycomb sandwich structures

Honeycomb sandwich structures are susceptible to liquid ingress, which causes a serious degradation of performance. Herein, a near-field microwave nondestructive detection technique was proposed to detect, identify, and quantitatively evaluate liquid ingress in honeycomb sandwich structures. Based on the microwave reflection spectrums, liquids of different polarity properties were identified. The amplitude of reflection microwaves was found nearly linear with respect to the height of the intruding liquids in the near field of the coaxial adapter probe. A simple characteristic peak method (CPM) based on line scans was presented and applied to quantify the size of liquid ingress region, and it turned out to be quite accurate with relative errors less than 0.5%. In summary, the near-field microwave testing technique proposed in this study is effective to detect, identify, and quantify liquid ingress in honeycomb sandwich structures.     

Al质蜂窝夹芯板非线性动力学分析

基于经典叠层板理论和几何大变形理论.研究了四边固支Al质蜂窝夹芯板的非线性动力学问题.在考虑横向阻尼的影响下,利用Hamilton变分原理建立了蜂窝夹芯板受横向激振力作用时的受迫振动微分方程,通过振型正交化将蜂窝夹芯板的受迫振动微分方程简化为双模态下的动力学控制方程,同时利用Runge-Kutta法数值模拟了系统的非线性动力学行为.结果表明:由于芯层六角形胞元结构的影响,使得蜂窝夹芯板的振动对横向激振力幅值的变化非常敏感;第一阶模态下的最大振幅总要大于第二阶模态下的最大振幅,横向激振力幅值在不同的取值范围时,蜂窝夹芯板存在不同性质的动力学现象,在横向激振力幅值较小阶段,系统总是呈现单倍周期运动.当横向激振力幅值增加到一定数值时,系统呈现出从周期运动向倍周期及混沌等复杂运动形式的转换.通过相应的弯曲振动响应实验.对数值分析结果进行了实验验证.     

UPA based 3D visualization of discontinuities in great thickness EBW seam

Electron beam welding(EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined.It is a complex high-temperature metallurgical process,and the quality of welding may deteriorate because of defects caused by improper welding parameters,especially in the EBW of thickened aluminum alloy plate.Ultrasonic phased array(UPA) technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam.In present research,a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe,and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction.This large number of B-scan images were stacked to construct the volume data,with which the 3D image of the weld discontinuities were reconstructed,and the 3D visualization was realized.More details about weld discontinuities' spatial distribution and orientation were revealed,and this approach also made the results of non-destructive ultrasonic testing more easily to understand.     

UPA based 3D visualization of discontinuities in great thickness EBW seam 1

Electron beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined.It is a complex high-temperature metallurgical process,and the quality of welding may deteriorate because of defects caused by improper welding parameters,especially in the EBW of thickened aluminum alloy plate.Ultrasonic phased array(UPA) technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam.In present research,a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe,and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction.This large number of B-scan images were stacked to construct the volume data,with which the 3D image of the weld discontinuities were reconstructed,and the 3D visualization was realized.More details about weld discontinuities' spatial distribution and orientation were revealed,and this approach also made the results of non-destructive ultrasonic testing more easily to understand.     

铝蜂窝芯加工缺陷对蜂窝平压性能的影响

由于蜂窝芯结构的特殊性,在切削加工时容易产生各种加工缺陷,为研究铝蜂窝芯材料加工缺陷对于其力学性能的影响,对铝蜂窝芯在平面压缩载荷作用下的力学响应进行了研究.通过铝蜂窝芯铣削实验,得到了撕裂毛刺、压溃翻折、开裂脱胶等典型加工缺陷,同时建立了含有加工缺陷的蜂窝芯有限元模型,通过压缩实验验证了模型的可行性,分析了不同加工缺...     

Beam shaping to enhance zero group velocity Lamb mode generation in a composite plate and nondestructive testing application

Zero group velocity (ZGV) Lamb modes have already shown their potential in nondestructive testing applications as they are sensitive to the sample structural characteristics. In this paper, we first consider an aluminum sample to validate a method based on the beam shaping of the generation laser. This method is proven to enhance ZGV Lamb modes in aluminum, and then advantageously applied to a composite material plate. Finally, based on the proposed method, scanning the sample over healthy and flawed zones demonstrates the ability to detect subsurface flaws.