碳纤维复合材料缺陷的超声检测及材料力学性能仿真研究

碳纤维复合材料内部结构的健康程度将直接影响到零部件的整体性能.采用高频超声衰减法对碳纤维复合材料进行内部无损检测.在超声波频率为30 MHz、探头距离工件表面1 cm、等离子水介质条件下,通过超声C扫描、X扫描,分析和确定内部缺陷位置及形状,并通过剖切试样,采用光学显微形貌表征对内部缺陷进行确证.采用ABAQUS对层间...     

复合材料层压板钻孔分层激光超声检测方法

飞机复合材料结构钻孔分层的定位、定量检测是无损检测领域的难点之一,也是航空制造领域亟待解决的安全问题之一,激光超声检测技术是解决该问题的可能途径。试验验证利用激光超声检测复合材料钻孔分层的技术可行性。制备复合材料层压板钻孔试样,研究热弹性条件下脉冲激光在复合材料中产生超声波的宽频带特性,提取出满足检测灵敏度、分辨力要求并具有良好信噪比的超声信号;分析近孔边缘分层界面对声传播规律的影响,得出钻孔边缘分层缺陷的激光超声表征方法;采用脉冲反射法、透射法对复合材料钻孔试样进行激光超声C扫描检测,获得钻孔分层缺陷的形貌、尺寸和位置特征。研究结果表明,激光超声检测技术是解决飞机复合材料结构钻孔分层检测问题的有效手段。     

军机复合材料层压板超声相控阵检测的CIVA仿真与试验

基于军机复合材料层压板的结构损伤特点,利用相控阵超声检测众多参数的可调节性,采用固定单一因数的方法,通过CIVA仿真和试验结果对比,分析了不同参数对检测结果的影响,对军机复合材料层压板超声相控阵检测方案的制定具有重要意义。     

虚拟超声检测仪器系统的研究

将虚拟仪器技术运用到超声检测仪的设计中,结合现代计算机技术开发出虚拟超声检测仪器系统,该系统具有功能全,适于现场实时检测,界面友好等优点。     

复合材料低速冲击损伤超声红外热波检测能力评估

为评估超声红外热成像对复合材料低速冲击损伤的检测能力,提出了评估流程和评估标准。设计并制作了复合材料层合板,分别采用超声红外热成像和超声C扫描两种方法对不同冲击能量下的冲击损伤进行了检测研究,以超声C扫描结果作为参照,对比分析了超声红外热成像的检测结果并对损伤大小进行了定量识别。结果表明:超声红外热成像不仅能够对冲击损伤进行准确的定位,还能有效地检测出冲击引起的纤维断裂、基体开裂和分层等具体的损伤形式,检测速度快,非常适合用于在线检测;与超声C扫描相比,超声热成像方法对冲击损伤大小的识别误差小于6%,检测精度较高,满足检测要求。     

基于敲击法的复合材料损伤检测系统设计

针对传统敲击法操作难度高、可靠性差以及检测效率低的问题,基于STM32单片机设计了复合材料损伤检测系统.系统利用振动传感器采集敲击响应信号,并基于单片机软件进行了敲击响应信号的分析和敲击脉宽检测,实现了复合材料损伤检测工作的智能化控制与处理,减少了人工操作对经验的依赖性,显著提高了检测可靠性与工作效率.     

利用超声成像分析不同复合材料层压结构冲击损伤行为

复合材料各向异性和吸能的特点,在受到外来冲击作用时容易产生损伤,呈现表里迥然不同的损伤行为和分布规律。为研究不同复合材料层压结构的冲击损伤行为,设计制备树脂传递模型工艺(Resin transfer molding, RTM)缝合和预浸料复合材料层压结构两种不同成型工艺的试样,通过冲击试验模拟复合材料在外力作用下产生的冲击损伤,采用超声反射法,通过点聚焦换能器对试样进行超声B扫描成像,揭示两种复合材料层压结构试样内部断面损伤行为及其扩展规律。试验结果表明,冲击引起的试样内部损伤比表面损伤要大得多;随着冲击能量在试样内部传递,会在不同深度铺层产生新的损伤,而且损伤分布并不仅沿层间界面扩展;冲击点附近和远离冲击点附近的内部损伤具有明显不同的分布规律;RTM缝编与预浸料复合材料结构呈现明显不同的损伤行为,其中RTM缝合复合材料结构中的纵向缝线,对冲击损伤在试样内部沿层间的扩展有显然的阻止作用。研究结果对更好地理解复合材料的损伤行为、寻找新的改进复合材料层压结构损伤行为的机制有非常重要的指导意义和帮助。     

非线性超声理论在金属基复合材料结构应力检测中的应用

金属基复合材料结构是金属层与非金属层多层粘接而成的复合结构,非金属层的应力行为主要体现在粘接面上,利用应力一时延模型测量应力,非金属层的深层反射回波信号非常微弱,给各层信号的识别存在极大的困难,不能准确估计时间延迟.文中从非线性超声理论出发,提出运用非线性超声的二次谐波非线性系数进行非金属层应力检测,实验结果表明非线性系数可以表征应力.     

碳纤维增强复合材料的超声无损检测

本文介绍了通过对超声信号的频谱分析,利用超声信号的频谱特征参数无损测量碳纤维增强树脂基层压板复合材料微气孔含量、纤维体积含量的新方法。     

复合材料冲击损伤高分辨率超声成像检测与损伤行为分析

冲击损伤是复合材料结构易产生的一种危害性缺陷,针对碳纤维复合材料层压结构特点,分析脉冲超声波在复合材料中的反射特性,当能减小入射声波脉冲的时域占宽,提高其品质,可显著改善超声检测表面盲区和纵向分辨率。利用入射声波在冲击损伤区形成的反射信号及其渡越时间可确定冲击损伤的深度和大小。研究采用高分辨率脉冲超声B扫描和层深C扫描(T扫描)成像方法,可揭示复合材料内部冲击损伤及其大小与沿厚度方向的分布特征,进行复合材料冲击损伤量化评估与损伤行为可视化分析。试验结果表明,在入射脉冲单周脉冲特性条件下,当来自复合材料缺陷的回波信号的渡越时间达到入射声波脉冲时域占宽的一半左右时,即可清晰地提取到时域可分辨的缺陷回波信号,使超声检测表面盲区和纵向分辨率达到单个复合材料预浸料铺层的厚度,约0.13 mm。利用超声断面B扫描成像,可以形象地再现复合材料中冲击损伤的断面分布与扩展情况以及损伤的深度等确切信息。采用超声T扫描成像,则可以直观地再现冲击损伤在复合材料铺层方向的分布及其损伤区域(面积)等定量信息。二者的结合则为揭示复合材料冲击损伤的3D分布及其特征提供一种超声成像检测量化评估和损伤行为可视化分析方法。     

Ultrasonic inspection system for powder metallurgy parts

The demand for powder metallurgy (P/M) parts in its traditional automotive market is predicted to grow, but future sector expansion depends directly upon its capability to manufacture zero-defect parts for industries such as aerospace and medicine. The lack of adequate inspection systems has important implications from the point of view of quality assurance, since it increases the costs, time and wasted material. In recent years the applicability of several techniques for the inspection of P/M parts has been investigated, such as Eddy current testing, computer tomography or X-ray imaging, but studies have revealed that all of them have deficiencies that make them unavailable for a complete and reliable flaw detection and density defect recognition. A new inspection tool has been developed based on pulse echo ultrasonic technology combined with robotics, which makes it possible to provide a global density map of sintered.     

航空复合材料车间物料配送系统的研究

针对复合材料车间物料供应中存在的问题,提出改被动的物料供应为主动的物料配送.通过分析物料配送所需的信息,建立物料配送模型,并研究物料配送的作业流程.在此基础上开发了复合材料车间物料配送系统.     

Ultrasonic pig for submarine oil pipeline corrosion inspection

This paper introduces the design and development of an ultrasonic pig used for submarine oil pipeline corrosion inspection. Structure and functions of the equipment, as well as ultrasonic data acquisition system and off-line signal processing method are presented. The pig adopts a train-like structure including driver cups, batteries, ultrasonic transducers and data acquisition unit, which can detect and locate the corrosion of inspected pipeline. The data acquisition system is designed based on a digital signal processor and field programmable gate arrays structure to sample, process and compress the ultrasonic data and then store them in a hard disk. The off-line signal analysis method adopts a non-phase delay peak extraction algorithm to accurately calculate the pipe wall thickness. According to the thickness of each detected point, an ultrasonic image is traced by false color image, and then the potential defects are recognized by using a 3 × 3 grids template and classified according to American Petroleum Institute Standard. Both experimental and engineering testing results show that the pig is of perfect performance and could inspect defects greater than 10 × 10 mm² successfully. The article is published in the original.     

Integrated laser/CMM system for the dimensional inspection of objects made of soft material

The applications of the coordinate measuring machines (CMMs) with a contact trigger probe to the dimensional inspection of manufactured products are restricted to the parts made of hard material, such as steel. By combining the laser and CMM, the applications of the CMMs can be extended to the inspection of objects made of soft materials, such as foils, plastics, wood, wax and clay materials. In this research, replacing the contact probe with an inexpensive laser sensor is attempted so as to eliminate the possible deflection of the component being measured when using contact probe. By combining a laser sensor with the existing automated inspection environment, a CAD-directed, three-dimensional coordinate sampling system which can perform non-contact dimensional inspection is developed.     

基于光纤光栅传感器的复合材料损伤识别系统

利用光纤布拉格光栅(FBG)构建了传感器网络;结合小波分解与重构算法、频谱分析和支持向量多分类机算法研究了碳纤维复合材料板损伤的模式识别算法。首先,对带有不同损伤模式的复合材料结构进行冲击试验,探索损伤模式与信号特征之间的关系。然后,对信号进行小波分解与重构去除基线干扰;采用傅里叶变换频谱分析提取信号幅频特性,构建了复合材料结构损伤模式识别方法。最后,将提取的信号幅频特性作输入,复合材料结构损伤模式作输出,利用支持向量多分类机,实现了复合材料结构损伤模式识别。在500mm×500mm×2mm的碳纤维复合材料板中心,选定200mm×200mm的实验区域,对30组测试样本进行了损伤模式识别。实验结果表明:29组损伤模式得到了准确识别,正确率为96.7%。研究结果为碳纤维复合材料板的损伤模式识别提供了一种可靠的方法。     

An automated inspection system for stents

In this paper, the automated inspection of stent manufacturing is presented. It was developed and applied to acquire, process, and analyze the image data of stents using a line-scan camera and automated multi-axes scan mechanics to acquire the image data during the scanning process. A stent is a wire-metal-mesh tube used to prop open an artery during angioplasty. The stent is collapsed to a small diameter and put over a balloon catheter. It is then moved into the area of the blockage to restore normal blood flow and keep an artery open. A cardiovascular stent has hundreds of critical features with tight tolerances. They must be 100% inspected for dimensional conformity, and also for visual defects. The designed automated stent-inspection system utilizes a high-resolution line-scan camera to generate a flat, unrolled view of the stent, and was developed by Carinthian Tech Research CTR-AG. A novel approach is proposed for automatic error detection in stents. Image-processing-based algorithms are applied and work is under way for producing fully automated algorithms. The system generates a large, highly detailed image of the entire stent pattern in a few seconds (typically 20 s and the error detection in 10 to 15 s). Manufacturers of stents can benefit greatly from this new technology, which suits the particular inspection needs of the 100% quality requirement of stent production. The technology continues to evolve and take advantage of the latest developments in the growing field of digital optics, imaging, and computer capabilities.     

Automated inspection system for headlamp reflectors

Up to now the quality control of headlamp reflectors for vehicles has been visually made by inspectors (100%-control). The results depend on the daily constitution and attention of the inspectors. In many cases, those “human factors” lead to dissatisfactory quality control and rejects due to assumed defects. To avoid this and to accordingly reduce production costs and save the environment, a manufacturer of image processing systems and the three biggest manufacturers of car reflectors in Europe have initiated a project with the intention of solving the current problems. This article gives an overview of the project under the aspect of the economical automation of the whole process of the car reflector inspection. The project began in May 2002 and finished in December 2004 and was supported by the European Commission under the 5th framework competitive and sustainable growth, FINDER, project no. G6RD-CT-2002-00668 [EC-research-program, 2001, Fast intelligent defect recognition system (FINDER)]. The work described in this paper is a summary of the technical reports from the authors made for this project [4–8].     

宽幅胶片弊病在线检测系统

本文介绍了一套用于宽幅胶片生产线整理工序的弊病在线检测系统，该系统用来实时检测胶片表面常见的弊病。系统采用2台线阵CCD摄像机同步成像，940nm的LED面阵光源提供照明，利用单行处理、多行判断的快速弊病检测算法及时发现弊病。现场运行结果表明，系统能够完成对运行速度为90m／min，宽幅为1300mm的胶片表面弊病的检测任务。     

A review of tangential composite and radial composite gear inspection

This paper presents an overview of the literature on tangential composite and radial composite gear inspection. It demonstrates – by dealing with their origins and key milestones in their history and development – the important role that inspections play in terms of the functional nature of the gears concerned. This comprehensive consideration of the subject also attempts to demonstrate how the lack of clear guidelines and standards designed to unify the criteria applied to testing, the interpretation of results and calibration of equipment, along with the number of simultaneous variables involved in trials of this type, leads to doubts (including with respect to the actual standards concerned) as to whether these tests are valid, or instead accepted only has partial validations. Even so, the repeatability of the experimental data demonstrates not only their metrological potential, with respect to functionality, but also the fact that they are both effective and original