The Contrastive Study Between Defect Detection Of Fillet Weld Based On Magnetic Memory Testing And Finite Element Simulation

Fillet weld is a widely used welding seam in the steel structure, which is made in extremely bad environment, and if damaged, can cause safety accident. So it is especially important to detect the fillet weld. Metal magnetic memory technology is a new nondestructive testing technology, which can not only detect the macro damage, but also detect the hidden damage.In this paper, I will focus on magnetic memory technology which is applied to the detection of fillet weld, and the change rule of magnetic memory signal through experiment and finite element simulation.Based on theoretical analysis and magnetic memory detection experiments of intersection of piping and pressure vessel weld, the result shows the normal magnetic memory signals, the tangential magnetic memory signal peak to peak and gradient values in the vicinity of default fillet weld are all increased with the increasing of the internal pressure. And for fillet weld of intersection pipes, the peak value of obliqued weld is larger than that of straight seam, which shows the peak value is increased and the degree of damage is increased with the angle of fillet weld.Through the finite element simulation of the fillet weld under the action of internal pressure by the ANSYS finite element software, we will obtain the stress distribution and then carry out magnetic coupling of the fillet weld. As ANSYS can not directly simulate the magnetic coupling, it is necessary to find a reasonable model and method to carry out ANSYS analysis.In this paper, I will use ANSYS for fillet weld stress analysis, and obtained stress distribution in different internal pressure, then got the equivalent relationship between force and permeability by conservation of energy principle, which will change the magnetic coupling problem to ANSYS magnetic field analysis of the problem, and then draw the magnetic induction intensity under different stress distribution. Finally, I will compare the finite element simulation results with magnetic memory test results, and the obtained results of the magnetic memory measured curve and the magnetic induction intensity distribution curve of the finite element simulation are consistent. Finally, the magnetic memory testing can be applied to the engineering practice, and promote the development of the field of magnetic memory testing.