Modeling and Investigation of Semi-elliptical Cracks in the Weld Seam of Pressurized Cylindrical Tanks

 This work examines the finite element model of three-dimensional semielliptical fractures in a cylindrical pressure tank. The three-dimensional semielliptical cracks in cylindrical pressure tubes are investigated using the ANSYS finite element analysis software. The primary goals of this study are as follows. First, codes for the ANSYS parametric design language (APDL) were created to make it easier to simulate various semi-elliptical fracture topologies in cylindrical pressure vessels. The second is to use these codes to investigate the impact of certain problem factors on the normalized stress intensity coefficient distribution for cracks. Some of these properties include the crack depth ratio (DDR) and crack aspect ratio (ACR). Furthermore, a semi-elliptical fracture in the tank body connection at the weld seam is considered to investigate the effect of shape transfer on the normalized stress intensity coefficient distribution. By reducing the thickness, we see the increase and improvement of the stress intensity factor. Also, cracks with ac = 0.4 are a dangerous type and have a faster growth and progression rate than other types of ac = 0.6, 0.8 and 1. Cracks with ac = 1 have the lowest stress intensity factor. In the case of at = 0.8, which has the lowest possible thickness, the stress intensity factor is the highest. The highest stress intensity coefficient is at the crack tip. With the increase of ac, a decrease in the stress intensity factor is seen, in which case the cracks with at = 0.8 and the lowest thickness have a higher stress intensity factor, which is at the top of the crack. ac = 1.2 has the lowest stress intensity factor. As seen, the higher the aspect ratio, the smaller the values of stress intensity factors. In other words, the higher the relative crack depths, the higher the stress intensity factor.