Enhanced Subsurface Analysis Using Proper Orthogonal Decomposition in Nonstationary Thermal Wave Imaging

Russian Journal of Nondestructive Testing - Active infrared thermography (AT) has been evolved as a prominent nondestructive testing technique for in-situ monitoring of defect-free composite...     

Deep and Handcrafted Feature Fusion for Automatic Defect Detection in Quadratic Frequency Modulated Thermal Wave Imaging

Russian Journal of Nondestructive Testing - Recent advancements of nondestructive testing and evaluation (NDT&E) with machine learning, artificial intelligence, and the internet of things...     

Statistical Analysis of Defect Dection in Glass Fiber Reinforced Polymers Using Frequency Modulated Thermal Wave Imaging

Russian Journal of Nondestructive Testing - Active infrared thermography (AIRT) has emerged as an extensively applied non-destructive testing and imaging (NDT&I) methodology for examining...     

混凝土柱内部缺陷的红外热成像无损检测

以含有缺陷的混凝土结构试件为研究对象,运用传热学理论,对热流在试件内部的传递过程进行了仿真分析,获得了试件表面的温度信号.结果表明,缺陷处与完好材料处对应试件表面温度存在着明显差异,红外热成像无损检测技术可用于实现对混凝土内部缺陷的检测.     

Non-Stationary Thermal Wave Mode Decomposition: A Comparative Study of EMD,HVD, and VMD for Defect Detection

Russian Journal of Nondestructive Testing - Frequency coded non-stationary thermal wave imaging (NSTWI) has been evolved as viable active infrared non-destructive testing technique for inspecting...     

Investigation of High-Frequency Guided Wave Modes Applicability in Defect Detection Using Phased Array Ultrasonic Transducer

Russian Journal of Nondestructive Testing - An ultrasonic phased array scanning method was used for lamb wave evaluation of surface and in-depth defects in a steel plate. The ultrasonic guided wave...     

Effectiveness of Biomaterial Coating on Bone Density Diagnosis Using Modulated Thermal Wave Imaging: A Numerical Study

Russian Journal of Nondestructive Testing - Active thermography is one of the promising painless techniques for bone density detection. It can defeat constraints of conventional diagnostic...     

Comparative Data Processing Approaches for Thermal Wave Imaging Techniques for Non-Destructive Testing

Thermal non destructive testing is a whole-field, non-contact and non-destructive inspection method used to reveal the surface or subsurface anomalies in a test sample. This paper describes a novel modelling and simulation technique of a three dimensional pulse compression method for non-stationary thermal imaging. This method requires much lower peak power heat sources than the widely used conventional pulsed thermographic methods (PT and PPT) and requires less time than sinusoidal modulated Lock-in Thermography (LT). In addition, simulation results obtained with the proposed techniques are compared with the conventional phase-based thermal imaging techniques (PPT and LT).     

基于Lamb波时间反转的复合材料结构损伤监测

采用Lamb波时间反转法,对复合材料结构进行在线连续健康监测。利用板中Lamb波时间反转法的原理和自聚焦特点,运用时间反转方法,通过传感器网络的布置,激励并接收Lamb波,从而对复合材料结构实现损伤监测。该方法无需结构无损情况的基准信号,能够对有损结构进行快速的损伤定位及损伤大小判断。采用改进的RAPID算法进行损伤成像,得到的损伤图像可将损伤情况可视化。实验研究表明所提方法可行和有效。     

飞机复合材料红外热成像检测技术的研究

简要介绍了红外热成像检测技术的基本原理和分类,应用该技术分别对飞机复合材料层压板平底孔和蜂窝结构中分层和积水进行检测,并进行了一定分析.     

多种噪声下输油管道应力波波达时刻的检测

从小波变换的多分辨率特性和B样条小波能进行信号突变点检测的特性出发，研究了针对输油管道中冲击应力波波达时刻的检测方法。利用小波变换对含有多种噪声的应力波信号进行了多分辨率的分解，提取了有用信号。利用B样条小波对提取的有用信号的突变点位置进行判断，根据应力波到达两相邻检测点的波达时刻计算冲击点的位置，实现盗油点的定位。通过实测数据分析，得出该方法在输油管道的防盗检测中是可行的。     

Fast Defect Detection in Textured Surfaces Using 1D Gabor Filters

In this paper, we present a fast machine vision method for the automatic inspection of defects in textured surfaces. Traditional 2D Gabor filtering schemes have been shown to be very effective for detecting local anomalies in textured surfaces of industrial materials. However, they are computationally expensive and sensitive to image rotation. In order to alleviate the limitations of 2D Gabor filtering, we first use a 1D ring-projection transformation to compress a 2D grey-level image into a 1D pattern, and then employ a 1D Gabor filter to detect defects embedded in a homogeneous texture. Given a problem with image size N × N and filter window W × W, the computational complexity can be reduced significantly from O(W ² N ² ) in the 2D Gabor space to O(WN ² ) in the 1D Gabor space, and the detection results are invariant to rotation changes of a texture. The experiments on structural textures such as a wooden surface, an LCD display, and a machined surface, and statistical textures such as granite, leather, and sandpaper have shown the efficiency and effectiveness of the proposed method. ID="A1" Correspondence and offprint requests to: Dr Du-Ming Tsai, Department of Industrial Engineering and Management, Yuan-Ze University, 135 Yuan-Tung Road, Nei-Li, Tao-Yuan, Taiwan. E-mail: iedmtsai@saturn.yzu.edu.tw     

Thermography Sequence Processing and Defect Edge Identification of TBC Structure Debonding Defects Detection Using Long-Pulsed Infrared Wave Non-Destructive Testing Technology

Russian Journal of Nondestructive Testing - General infrared image processing and analysis methods mainly include non uniformity correction, enhancement, noise reduction, segmentation, etc. The...     

一类Neutral时滞系统的鲁棒故障检测方法

针对一类具有不确定输入的 Neutral时滞系统 ,应用 H∞ 控制理论和 L yapunov原理得到了系统的带记忆状态观测器的鲁棒故障检测方法。证明并给出了观测器对不确定性具有 L2 范数界的渐近稳定条件和增益阵设计的线性矩阵不等式(L MI)方法 ,同时使残差体现了对故障信号响应的灵敏度。仿真算例表明了该方法进行鲁棒故障检测的有效性。     

基于群速度校准的超声导波技术及在复合材料缺陷检测中的应用

由于在复合材料板中传播的超声导波具有偏斜效应,使得理论群速度与试验测得的群速度不一致,因此需要对群速度幅值和传播方向进行校准。数值计算复合材料板中超声导波频散方程得到S0模态各个方向的理论相速度频散曲线。运用群速度校准法则对S0模态群速度幅度和传播方向进行修正。校准后的理论群速度与试验测得的群速度较为吻合。试验中采用频率200 kHz的S0模态对碳纤维复合材料板中的模拟缺陷进行检测。结果显示采用校准后群速度和试验测得的群速度可准确定位缺陷,且具有很好的一致性。因此,采用群速度校准法则可有效提高各向异性复合材料结构中超声导波的缺陷定位和识别能力。     

Trends in Using Passive Thermal Imaging Diagnostics in Power Engineering and Industry

The regions of application of thermal imaging technique for testing the heat shielding of building structures, diagnostics of smoke pipes, boilers, cooling ponds, and thermal service lines are described.     

Chirp Z Transform Based Barker Coded Thermal Wave Imaging for the Characterization of Fiber Reinforced Polymers

Russian Journal of Nondestructive Testing - The phase-based post processing approaches gives better defect detection in non stationary thermal wave imaging for subsurface analysis of materials in...     

不同幅值激励的复合材料板时间反转损伤识别方法

复合材料结构受到冲击时会产生基体开裂、层脱等损伤,通常情况下损伤界面保持闭合接触。小幅值激励下应力波产生的应变极小,损伤界面仍处于闭合的线性状态,时间反转重构信号不能表明损伤的存在与否。针对该问题,采用不同幅值激励的时间反转方法进行损伤检测与识别,利用时间反转重构信号与激励信号的相关系数构造了损伤指数,开展了基于压电作动/传感阵列的复合材料板损伤识别与定位的实验研究。实验结果表明:小幅值激励下作动-传感的完整路径和损伤路径上的时间反转重构信号与原始激励信号相似程度均很高,不能表征结构中的损伤;而增大激励幅值至某一阈值后,损伤路径上的损伤指数明显增大,而完整路径上的损伤指数变化不明显;利用该方法准确地识别与定位了板中损伤。     

基于超声导波技术对弯管中缺陷检测的实验研究

利用超声导波技术在弯管中进行了缺陷检测的实验研究.利用周向均布的长度伸缩型压电陶瓷片激励特定频率的纵向模态L(0,2),对90°弯管中的人工周向缺陷和结构缺陷等进行了检测,分析了周向缺陷尺寸的变化对缺陷回波和端面回波幅值大小的影响.对弯管中同时存在多个缺陷的情况进行了研究.实验结果表明,超声导波检测技术可以用于弯管中不同部位和不同类型的缺陷检测,这为利用超声导波对更加复杂的管道系统中缺陷检测作了有益探索.     

一种基于时间窗的多阶段混合流水车间调度方法

考虑同时包含单处理机和批处理机的多阶段混合流水车间调度问题,设计一种基于时间窗的蚁群算法,以最小化最大完工时间为优化目标。在解决整体调度问题的过程中,通过蚁群算法实现工序分派、排序、组批三个阶段的协同优化调度;另外在工件组批阶段加入时间窗策略,利用前瞻性算法动态构建组批方案,通过分析批处理机的时空关系设计合理的组批时间窗,以获得较高的机器利用率。试验结果表明,与无时间窗的蚁群算法相比,时间窗策略在确保最小化最大完工时间的同时,提高了批处理机的利用率;与CPLEX相比,基于时间窗的蚁群算法在最大完工时间和计算效率方面均有较大优势。蚁群算法与时间窗的结合兼顾了多个阶段多种机型的生产特点,适用于解决多阶段混合流水车间的调度问题。