FABRICATION AND ASSEMBLING ERRORS INFLUENCE ON THE FATIGUE STRENGTH OF THE SPHERICAL TANKS SHELL-THEORETICAL APPROACH

In the paper are summarized the major and most often encountered manufacturing errors influence on the stress concentration factor and on the state of stress of the spherical tanks shell, used for the storage of liquefied gases, discontinuous equatorial supported, complex loaded. There are presented stress concentration factor calculus formulas to be used to take into account the welds flaws. The spherical tanks shell is subjected to low cycle fatigue stress, especially due to the extension of the working time period (often encountered in nowadays practice). So it is evaluated the low cycle fatigue strength/number of cycles of the spherical tanks shell both in the absence of fabrication and assembling errors and taking into account these kinds of errors. Here is presented the theoretical approach. Another part will deal with the calculus approach and the conclusions.