In this paper, two surface treatment technologies, i. e. sand blasting and plasma electrolytic oxidation (PEO), are respectively applied on magnesium alloy to increase joint strength of glass fibre reinforced polyphenylene sulphide (PPS)-Mg composite. The influence of treated metal's surface structure on the joint strength between PPS and Mg was carefully investigated. Three rupture mechanisms have been proposed, i.e. direct PPS peeling off, PPS rupturing at the interface as well as metal outmost layer detaching by the adhesion of PPS. Compared with the sand blasting technique, PEO treatment can achieve a much higher joint strength due to the formation of porous and uniform surface structure on the Mg alloys. This kind of structure is favourable for the joint strength between Mg and PPS due to the strong mechanical riveting. PEO technique is a promising technology to improve the joint strength between plastic and metal.

Highly enhanced joint strength of direct-injection-moulded polyphenylene sulphide-magnesium composite by PEO coated interface

Friction spot joining of aluminum AA5052 and short glass fiber-reinforced PPS: Effects of material properties and process parameters on joint structure and strength

The process of detecting metal materials can be affected by factors such as the size of the eddy current probe and the magnitude of the current. High frequency eddy current sensors have been widely used in the detection of material internal flaws because of their advantages, such as a non-contact structure and relative speed. However, the process of detecting metal materials can be affected by factors such as these. This study analyzes the influence of measurement parameters such as the inner and outer radius and height of the coil, the number of coils and layers of the high-frequency eddy current structure on the measurement results through a combination of finite element simulation and experimental verification. Additionally, this study quantifies and discusses various factors affecting the measurement accuracy, and it proposes an optimization method for the high frequency eddy current structure. The purpose of this study is to address the issue of measurement accuracy.

Simulation Study of Parameter Sensitivity for High Frequency Eddy Current Measurement

Friction spot riveting of AA6061-T6 and polypropylene

Fundamental theory and methods are investigated of inspecting tubing and casing simultaneously using pulsed eddy current testing by numerical simulations and experiments. The distribution and variation of eddy current field are given in the finite element simulation for the inspection of undamaged and corroded casing and tubing combinations, with tubing outer diameter 73.8 mm, wall thickness 5.7 mm, corrosion depth 1.25 mm, 2.5 mm, 3.75 mm, and casing outer diameter 141.5 mm, wall thickness 7.7 mm, corrosion depth 1.25 mm, 2.5 mm, and 3.75 mm, respectively. The results show that eddy current field propagates around and to the depth after the direct section of the exciting current is cut off and the intensity center of eddy current field shifts gradually from the inner side of the tubing to the casing, which forms the basis of analyzing inspection mechanism. Corrosion at a particular depth is related to a particular optimum time slice of the induced voltage (namely with deepest concave) and a highest sensitivity is obtained at this slice. The time associated with this slice is in accordance with the time when the intensity center of eddy current reaches the corrosion. Corrosion at different depths has different voltage time slices starting to show signal of defect, which can be used to estimate the depth of the defect in order to judge the defect coming from tubing or casing. Furthermore, sinking degree of the time slice reflects the size of the defect. All machined defects can be recognized in the experiments and the optimum time slice appears at 0.01 s and 0.008 s after the excitation current is cut off for the tubing corrosion of 1.25 mm and 2.5 mm, respectively. The optimum time slice appears at the last moment of cut-off period, 0.625, for the casing corrosion. Experimental results agree well with the simulations and show the existence of the optimum correspondence between depth of corrosion and starting time of the defect signal of time slice, relations between sinking degree of the time slice, and corrosion size.

https://www.mdpi.com/1424-8220/23/3/1135/pdf?version=1674979160

Xingxing Yu

Papers

Friction spot riveting of AA6061-T6 and polypropylene

Time-Domain Numerical Simulation and Experimental Study on Pulsed Eddy Current Inspection of Tubing and Casing

Real-time control of ship's roll motion with gyrostabilisers