Elastic stability analysis of loosely fitted thin liners – A proposed simplified procedure and evaluation of existing solutions

A Full 3D Finite Element Model for Buckling Analysis of Stiffened Steel Liners in Hydroelectric Pressure Tunnels

“…Results obtained for buckling pressure ( Figure 7) agree with those of inelastic models (Montel and Jacobsen), and, as expected, yield lower values than elastic buckling models predicted by El Sawy et al [21].…”

“…Based on results from FE models, El-Sawy [20] proposed the following regression solution for elastic buckling: El Sawy et al [21] studied the effect of local wavy imperfections on the elastic stability of cylindrical liners by using a 3D finite-element model, and derived empirical formulae that agree with Glock's model. …”

“…Hence, the first yield point would represent the critical buckling load if the liner were not restricted (i.e., linear elastic buckling). However, this is an inelastic buckling case: the elastic yield point is reached [11,21].…”

Steel‐lined pressure shafts – appropriate design for external pressure

“…Solutions based on elastic buckling theory were suggested by Glock [7] and, more recently, by Lo and Zhang [8] and Boot [9]. Comprehensive numerical studies with FEM were carried out by El-Sawy [10] and led to simplified formulae for calculating the critical external pressure p 0,cr [11]. All the individual studies assume only one dent over the circumference, as shown in Fig.…”

“…Formulae developed more recently are presented by El Sawy [11], Lo and Zhang [8], Boot [9], Thépot [15] and Madryas and Szot [16]. All these formulae, which consider only elastic stability behaviour, are presented and compared with each other by El-Sawy et al in [11]. In [10] El-Sawy also gives simplified formulae for inelastic stability behaviour.…”