To monitor 3D deformations of structural vibration response, a stereovision-based 3D deformation measurement method is proposed in paper. The world coordinate system is established on structural surface, and 3D displacement equations of structural vibration response are acquired through coordinate transformation. The algorithms of edge detection, center fitting and matching constraint are developed for circular target. A shaking table test of a masonry building model under Taft and El Centro earthquake at different acceleration peak is performed in lab, 3D displacement time histories of the model are acquired by the integrated stereovision measurement system. In-plane displacement curves obtained by two methods show good agreement, this suggests that the proposed method is reliable for monitoring structural vibration response. Out-of-plane displacement curves indicate that the proposed method is feasible and useful for monitoring 3D deformations of vibration response.
KEYWORDS: Earthquakes, 3D modeling, Sensors, Digital image correlation, 3D metrology, Electroluminescence, 3D image processing, Cameras, 3D image reconstruction, Image processing
Traditional contact sensors usually break with the failure of structures or model. To solve this issue, a stereovision-based 3D displacement measurement method is proposed to detect the whole process of structural deformations in this paper. A three-floor frame model subjected to earthquake excitation is tested with the proposed method in lab. Experiment results show good agreement with LVDT data during small deformation stage, this verifies that the presented approach is reliable. During large deformation stage, LVDT sensors are destroyed, the dynamic response curves of three-floor frame models are only acquired by the propose method. Experimental results prove that the proposed approach is feasible and useful for monitoring whole-process deformations of structures even at collapse stage.
To improve the inspection result repetition and reliability of manual ultrasonic method in NDT field, a portable ultrasonic
apparatus based on the phased array inspection technology is developed in paper. The apparatus is small, integrated and
portable, which can perform the shear wave and longitudinal wave detection, automatically transmit and receive sound
wave, accomplish data acquisition in real time, provide many imaging modes, and give comments of the damage. As
designed, the apparatus can implement different algorithm of the ultrasonic phased array inspection technology. With
proposed inspection scheme, a phased array reference block was practically detected in the lab. Experiment results
indicate the portable ultrasonic apparatus can factually imaging the flaws position, and the size and shape of flaws are
nearly consistent with the practical condition. Compared to the conventional ultrasonic testing system, the current
apparatus works more efficiently and reliably in the flaw detection and evaluation.
In order to improve inspection result repetition and flaw ration veracity of manual ultrasonic inspection of offshore
platform structure, an ultrasonic phased array inspection imaging technology for NDT of offshore platform structures is
proposed in this paper. Aimed at the practical requirement of tubular joint welds inspection of offshore platform
structures, the ultrasonic phased array inspection imaging system for offshore platform structures is developed, which is
composed of computer, ultrasonic circuit system, scanning device, phased array transducer and inspection imaging
software system. The experiment of Y shape tubular joint model of 60 degree is performed with the ultrasonic phased
array inspection imaging system for offshore platform structures, the flaws characteristic could be exactly estimated and
the flaws size could be measured through ultrasonic phased array inspection imaging software system for offshore
platform structures. Experiment results show that the ultrasonic phased array inspection imaging technology for offshore
platform structures is feasible, the ultrasonic phased array inspection imaging system could detect flaws in tubular joint
model, the whole development trend of flaws is factually imaging by the ultrasonic phased array inspection technology
of offshore platform structures.
Aimed at the practical requirement of tubular joints weld inspection of offshore platform structures of Shengli oil field,
the ultrasonic phased array inspection arithmetic for offshore platform structures is proposed. The integrated design of
ultrasonic phased array inspection imaging system for offshore platform structures is completed, the ultrasonic phased
array inspection imaging system for offshore platform structure is integrated on the basis of the each module and the
exploitation of subsystem, which is made up of computer, ultrasonic circuit system, scanning device and phased array
transducer. The ultrasonic phased array inspection experiment of T shape tubular joint model is performed with the
ultrasonic phased array inspection imaging system for offshore platform structures, the flaws characteristic could be
exactly estimated and the flaws size could be measured. Experiment results indicate that the ultrasonic phased array
inspection arithmetic for offshore platform structures is practical, the ultrasonic phased array inspection imaging system
could inspect artificial defects in tubular joint model, such as slag inclusion, crack, gas porosity, etc., the whole
development trend of flaws is factually imaging by the ultrasonic phased array inspection technology of offshore
platform structures.
The ultrasonic phased array inspection imaging system was developed in this paper, which is integrated on the basis
of the each module and the exploitation of subsystem, it is made up of computer, ultrasonic circuit system, scanning
device, phased array transducer and imaging software. The ultrasonic phased array inspection imaging system has the
functions of controlling ultrasonic transmission and reception, controlling sound beam steering and focusing, controlling
scanner moving, receiving flaw information and position formation, restructuring flaw image and commenting damage.
Experiment was done on the fillet weld block of T shape flat plate with some artifical flaws using the ultrasonic phased
array system, the flaws characteristic could be exactly estimated through comparing and analyzing the flaws position in
B-scan image and the waveform feature in A-scan curve, and the flaws size could be measured from the image of C-scan
and D-scan. Experiment results indicate that the flaws detected by the manual ultrasonic inspection technology could be
found over again by the ultrasonic phased array inspection technology, the flaws size measured by the latter is close to
the former, the whole trend of development of flaws are factually imaging by the latter.
A novel ultrasonic phased array detection system is developed for nondestructive testing (NDT). The purpose of the
system is to make acquisition of data in real-time from 64-element ultrasonic phased array transducer, and to enable real-
time processing of the acquired data. The system is composed of five main parts: master unit, main board, eight
transmit/receive units, a 64-element transducer and an external PC. The system can be used with 64 element transducers,
excite 32 elements, receive and sample echo signals form 32 elements simultaneously at 62.5MHz with 8 bit precision.
The external PC is used as the user interface showing the real time images and controls overall operation of the system
through USB serial link. The use of Universal Serial Bus (USB) improves the transform speed and reduces hardware
interface complexity. The program of the system is written in Visual C++.NET and is platform independent.
A phased array ultrasonic inspection system is being developed ot obtain electronically scanned ultrasonic images of the inside of steel structures for nondestructive evaluation. This phased array ultrasonic inspection system is made up of computer, scanner, motion controller, motor driver, ultrasonic emission, receiving & delay circuit, high speed data acquisition circuit and ultrasonic phased array transducer, this system has the functions of controlling ultrasonic transmission and receiving, controlling sound wave steering and focusing, controlling scanner moving, revceiving position information and flaw information, restructuring flaw image. Experimental tests were done on a steel testing block with side-drilled holes to simulate defects. The side-drilled holes could be detected and their diameters could be estimated from B-scan image, and B-scan image could show the location of side drilled holes clearly and does not have any ghost image.
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