LPG Tank Reinforcement Of Crack Repair

The defect of Liquefied petroleum gas spherical tank in service is mainlybased on cracks while the cracks in the inner surface account for a largeproportion. The ultimate strength of the spherical tank is significantly reducedand the carrying capacity is seriously affected because of the concentration ofstress made by the crack so that the spherical tank is dangerous to be used. Inrecent years, The usage of repairing reinforcement of crack defects in bridges,aerospace and mechanical maintenance industrial sectors is becoming more andmore widely, more and more mature. However, there are few studies on theengineering example of the repairing spherical tank. In this paper carbon fiberreinforced plastic (CFRP) wound technology is used for repairing spherical tankwith crack to make the LPG tank meet the purpose of safe operation. Theresearch result in this paper has a great reference value for the usage of LPGspherical tank.In this paper, the corresponding numerical simulation was carried out byusing finite element software. First of all, the1000m3LPG spherical tank isanalyzed in static under the design pressure. The maximum mises stress iscompared with allowable stress of material, and the feasibility of the finiteelement analysis method is verified. Secondly, the influence of cracks and pitson spherical tank strength are discussed respectively. Thirdly, the scheme usingtwo kinds of CFRP to repair reinforcement is designed, and compared with thespherical tank without repairing. Based on analyzing the strength of sphericaltank, the reasonable repair reinforcement scheme is determined. Finally, bychanging the width、thickness、number of layers and layer angles of the CFRPpasted, the effects of these parameters are discussed on the strength of sphericaltank, and the optimal scheme using CFRP to repair reinforcement has beenfound out.The results show that the most dangerous location of the crack is under theequator of the spherical tank, and with the equator line Angle of20°place. The transverse crack is much more dangerous than the longitudinal crack of LPGtank. the carrying capacity of the spherical tank will be greatly improved by thecrack burnishing the pit. Pasting a circle of CFRP on the great circle of sphericaltank defects can have better effect on repairing reinforcement of spherical tankin the pit. Width and thickness of the CFRP wrapped have a greater influence onthe spherical tank, while width is about2.4times and thickness is about0.5~0.6mm, the effect is best. The reinforcing effect of spherical tank is not obviousby numbers of layer, and the angle of layer has no effect on reinforcing sphericaltank.