共查询到19条相似文献,搜索用时 250 毫秒
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提出了一种大型武器装备液压系统快速故障诊断系统设计方案,介绍了用液压系统超声多功能检测仪对流量、压力进行非接触测量的原理,并建立了运用超声检测方法测量液压系统流量、压力的数学模型。 相似文献
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基于Hilbert变换的相位测量法与数字相关测相法的比较 总被引:2,自引:0,他引:2
介绍了希尔伯特(Hilbert)变换测量相位差和数字相关法测量相位差的原理,进行了比较研究和试验分析,讨论了各自使用效果、优缺点及其适用的场合。结果表明,在动态检测方面,利用Hilbert变换法更能对两路同频信号的相位差进行有效的检测,是今后的研究方向。 相似文献
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针对焊缝余高存在时,超声衍射时差法(time of flight diffraction, TOFD)B扫描可达性受限这一问题,提出了双椭圆法及纵横波复合法两种缺陷横向位置无损检测方法。根据探头和缺陷位置的几何关系,建立了缺陷定位测量的数学模型,利用确定的缺陷定位算法,分别对人工缺陷和焊接缺陷进行了定位检测。结果表明,双椭圆法在缺陷定位测量精度和操作实施过程上要优于纵横波复合法;采用双椭圆法,人工缺陷的埋藏深度及横向位置的平均测量误差分别为0.5和0.3 mm;焊接缺陷的埋藏深度及横向位置的平均测量误差分别为0.6和0.4 mm。所提方法克服了由于焊缝余高的存在,传统超声TOFD法B扫描不可达的问题,并为缺陷在焊缝中的横向位置检测提供解决办法。 相似文献
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基于声弹性效应,超声波可以无损检测出结构内部应力.利用建立的基于临界折射纵波的超声波法焊接残余应力测量系统,对低碳钢双丝焊纵向焊接残余应力进行了实时快速无损测量.使用激光全息小孔法对超声波法测量系统的测量结果进行了验证.对两种方法的测量过程和测量结果进行了对比.结果表明,超声波法测量结果可靠,声波法克服了传统应力测量方法费时、耗力、破坏、体积庞大等缺点,整个设备轻便,可单人手提.系统支持程序使测量操作简便,过程实时快速. 相似文献
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针对当前飞机地面空调送风环境复杂多样,在线流量检测缺乏高效手段的问题,提出一种基于DSP和FPGA处理系统的非接触式超声波气体流量计的在线流量检测方法,选用T1公司的DSP芯片,来负责流量检测过程中的控制以及对超声波信号的处理;选用Altera旗下的FPGA芯片,负责完成对超声波换能器的激励和接收信号的高频采样,设计了飞机地面空调流量监测系统,并通过测试验证了方法的可行性与适应性。 相似文献
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高温压力管道在线检测技术 总被引:1,自引:0,他引:1
为解决高温环境下管道在线无损检测技术问题,研究了高温状态下铁磁性材料的磁粉探伤方法,其检测灵敏度不低于常温检测的灵敏度。建立了高温环境下压力管道用碳钢中横波声速的测量方法,探讨了高温环境下碳钢中横波声速的变化规律,分析了高温环境下超声检测缺陷(反射体)位置的修正方法,解决了部分工程上急需解决的高温环境下焊缝缺陷的超声横波检测技术问题。具体介绍了适用于250℃以下工业管道的在线检测设备和方法。 相似文献
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Fawzi Emad Ph.D. Paul Haldemann M.S. Art Nispel B.S. Larry Logan M.B.A. 《JOM Journal of the Minerals, Metals and Materials Society》1996,48(2):24-27
In this paper, methods for measuring the quality of carbon anodes consumed in the commercial production of aluminum are discussed. The electrical and mechanical qualities of these anodes are important for the economic operation of the aluminum plant. While the investigation is ongoing, results from tests made at an aluminum reduction plant are included. The methods reviewed include direct resistivity measurement using core samples, ultrasonic measurement, the hammer method, analysis of the Hall effect, the four-probe method, and use of magnetic coils (various arrangements). 相似文献
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A comparative study of two non-destructive testing methods to assess near-surface mechanical damage in concrete structures 总被引:4,自引:1,他引:3
Concrete specimens displaying surface-breaking cracks are tested using two non-destructive testing techniques: the measurement of electrical resistivity and the transmission of ultrasonic surface waves. The capacity of each method to detect, localize and characterize the induced crack pattern—i.e. its width and depth—is investigated. The specimens are made of concrete with three different mixes. A major crack is induced in the middle of the specimen using a three point bending setup. As the bending strength is increased, three different loading levels are obtained. Both methods were able to correctly localize the main crack and follow its evolution. However, due to the complex crack pattern, the crack depth could not be estimated. Nevertheless, the ultrasonic technique was able to detect a change of state of the material before cracks became visible. As the crack intensity increases, variations of ultrasonic parameters in the apparently undamaged area surrounding the main crack were observed, thus highlighting the sensitivity of ultrasonic waves to distributed damage. The obtained results have also thrown bases for further research to couple resistivity and ultrasonic non-destructive methods. 相似文献