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Liu K.-L.,Fuzhou University | Zhao G.,Fuzhou University | Zhu Z.-B.,Fuzhou University | Zhu Z.-B.,Xiamen Special Equipment Inspection Institute | Zheng R.-B.,China Special Equipment Inspection And Research Institute
Petrochemical Equipment | Year: 2013

A cavity model was built at the outside of the cylindrical shell and contact pair was established between the outer wall of cylindrical shell and the inner wall of cavity. The effect of the contact and the gap between the cylindrical shell and the cavity to the critical buckling pressure was studied by the finite element analysis software ANSYS. The result show that the contact between the cylindrical shell and the cavity makes the critical buckling pressure of the cylindrical shell increased much, and the degree of increasing is relation to the gap existed between the cylindrical shell and the cavity. The bigger the size of the gap, the lower the level of the critical buckling pressure increases.


Zhu Y.-K.,Fuzhou University | Zhu Z.-B.,Xiamen Special Equipment Inspection Institute | Zheng R.-B.,China Special Equipment Inspection And Research Institute | Zhou L.-Q.,Fuzhou University | Liu K.-L.,Fuzhou University
Petrochemical Equipment | Year: 2014

Different thermal excitaiion methods in infrared thermography non destructive test (NDT) are discussed, and the application situation is introduced. The defects on inner wall of the pipe heated by electromagnetic induction were analyzed with the finite element process. The emphasis was placed on the temperature distribution on the outer wall and the relationship between different sizes of hole depth or bore diameter and the time. Influences and response measures on the method of thermal excitation based on electromagnetic induction in infrared thermography NDT is proposed.


Ye J.,Harbin Institute of Technology | Ye J.,Xiamen Special Equipment Inspection Institute | Gang T.,Harbin Institute of Technology
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2014

Signal processing was adopted in order to study the nonlinear behavior of ultrasound in diffusion bonding. First of all, diffusion bonding samples which contain typical defects were made by controlling the surface treatment before welding and changing the welding process. Ultrasonic testing was performed to obtain the data of ultrasonic signal which correlate with the joint states. Ultrasonic nonlinear effects of different states in diffusion bonding of stainless steel were analyzed from the points of view of the theory of ultrasonic nonlinearity in the joints of solid-phase connection, ultrasonic nonlinear images, microstructures and shear strength. The results showed that nonlinear ultrasonic testing was more sensitive to kissing bonds. It is possible to achieve nondestructive testing in diffusion bonding based both on C-scan images and ultrasonic nonlinear images to some extent.


Zhu Z.B.,Fuzhou University | Zhu Z.B.,Xiamen Special Equipment Inspection Institute | Yang X.X.,Fuzhou University | Chen L.-J.,Fuzhou University | And 4 more authors.
Advanced Materials Research | Year: 2013

Based on the viscoelastic material property of polyethylene pipe, software ANSYS was used to simulate and analyze the mechanical property of polyethylene pipe butt fusion joints with circumferential surface crack defects. The viscoelastic material creep parameters were characterized as Prony series and 1/4 node singular element was selected for meshing along the boundaries of the crack, then the stress intensity factor of polyethylene pipe butt fusion joints with circumferential surface crack was calculated under the uniform internal pressure. Through the finite element simulation, the result showed that polyethylene pipe were most likely to fracture failure when crack initiated. Thus the viscoelasticity of materials can be ignored when analyzing the stress intensity factor of circumferential surface cracks of polyethylene pipe. the main influencing factor of the circumferential crack defects was the ratio of the crack depth to the thickness of polyethylene pipe. © (2013) Trans Tech Publications, Switzerland.


Zhu Z.-B.,Fuzhou University | Zhu Z.-B.,Xiamen Special Equipment Inspection Institute | Chen L.-J.,Fuzhou University | Yang X.-X.,Fuzhou University | Chen J.-Y.,Fuzhou University
Petrochemical Equipment | Year: 2014

Aiming at polyethylene pipe's viscoelastic material properties, using ANSYS to analysis hot melt connector's mechanical properties of polyethylene pipe with ball hole cracks and predict the failure life through Matlab's program loop, compared to the polyethylene pipe's normal service life. Take Prony series analog PE pipe's viscoelastic mechanical properties, resulting in the maximum stress of polyethylene pipe is increased and the failure life of PE pipe is reduced while ball hole size increased. When the ball hole size exceeds a certain value, polyethylene pipe's life would not fulfill the requirements.


Zhu Z.B.,Fuzhou University | Zhu Z.B.,Xiamen Special Equipment Inspection Institute | Qiu X.,Fuzhou University | Zhong S.C.,Fuzhou University | And 4 more authors.
Advanced Materials Research | Year: 2014

We present defect detection of polyethylene (PE) pipes by using active infrared thermography technique. A finite element model was built to mimic the transient heat transfer in PE pipes, in which constant heat flux boundary condition was applied to the inner surface of the PE pipes. Various defects with different diameters and depths were simulated in PE pipes and they would affect the thermal distributions from which the relation between thermal images and defect sizes and locations would be established. An electrical heating bar, as the novel thermal excitation source, was employed in active infrared thermography experimental system. The finite element simulation results are well agreed with the one obtained from the infrared imaging experiments and it demonstrated that finite element numerical method can be an effective method to analyze infrared imaging. Furthermore, defects in heat fusion joints of PE pipes were fabricated and detected by the developed active infrared thermography. The experiment showed that active infrared thermography based on an electrical heating bar could provide a novel tool for nondestructive evaluation of PE pipes. © (2014) Trans Tech Publications, Switzerland.


Huang X.-B.,Xiamen Special Equipment Inspection Institute
Petrochemical Equipment | Year: 2014

The principle of infrared thermography(IRT) is introduced briefly and the application of IRT in the research of pressure equipment inspection is reviewed. The study statues are analyzed and summarized for on-line comprehensive inspection on ammonia refrigeration pressure piping, pressure equipment's wall thickness measurement, leakage inspection and monitoring, liquid level measurement, insulating layer measurement, thermoelastic infrared detection. Further more, the factors which affected measurement accuracy are analyzed, and the application prospect of the infrared thermography nondestructive testing technology is discussed.

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