The through - wall crack opening area is one of the main calculation parameters for the "leak before break" analysis of the piping system with postulated through crack. The existing methods for calculation of COA, in fact, consider the shell (pipe) to be a flat body and neglect the linear components across the pipe wall thickness (as in the theory of plate) both of load distribution as well as displacement field. Based on the combining weight function method the simple procedure for determination of approximate expression for the fundamental displacement field under polynomial loading of the crack surfaces in the shell as a sum of the uniform and linear components is proposed. Based on this method the formulas for calculating COA at the polynomial membrane and linear loading are derived. The comparison of the obtained COA values with results existing in the literature is performed for the cylindrical shell with axial and circumferential cracks. The contribution of the linear component of the COA to its total value has been estimated.
展开▼
