Theory Method Of Structural Damage Is Based On Fixed-roof Tank

When accidental overpressure occurring in fixed roof tank, safety requirements is thatthe damage happening in Roof-to-Shell joint. Therefore, from the perspective of theoreticalanalysis and numerical simulation to figure out the Roof-to-Shell joint stress distributions,and use the correct reasonable damage method for evaluation, the resulting destruction ofreasonable pressure calculation method, it is particularly important.Combined with the study research API650, to contrast Ansys with SafeRoof used in thereport at calculation the stress of tank if there is a difference. Therefore, two software usingthe same unit of stress analysis and damage evaluation method, there is no difference betweenits results. Axisymmetric unit have limitations, can't consider the actual structure of the tank,such as the connecting welds. Solid-shell combination element in Ansys build space modelsfor analysis, and the average equivalent stress value of linear path to reach material yieldlimit of damage evaluation. Results shows that the errors of space and two nodeaxisymmetric unit model in the allowed range. Space model can be used for analysis of stresscalculation and damage evaluation of the tank. This paper from theory to solve destructivepressure. Tank model for simplified, separate the tank roof and shell in connection, then usepowerful moment theory to analyze the roof and shell respectively, obtain the displacementand angle under the inside pressure, edge force and edge moment. According to deformationcompatibility conditions at the connection, getting the inside pressure expressing edge forceand edge moment, and so get the edges stress. Calculated using Ansys analysis of the roofand shell stress of their respective coefficients in the proportion, combined and joint failureevaluation of edge stress intensity theory IV. When the equivalent stress reaches the materialyield limit, that is, as the pressure in tank is the failure pressure at the connection. And Ansyssimplifies tank models, by numerical simulations to verify theoretical failure pressure ofcorrectness. Due to theory damage pressure derivation of simplified model is not consideredangle and weld, actual structure of tank, so will its for calculation storage tank actualstructure model of damage pressure, whose value is greater than the numerical simulationresults. By comparison between experiment and numerical simulation analysis shows thisarticle average of the equivalent stress along the wall thickness reaches damage evaluationmethod of the material yield limit is right.