Creep induced contact and stress evolution in thin-walled pipe liners

Finite element simulations of the contact conditions and stresses which evo lve as a thin walled polymeric pipe liner deforms under uniform pressure ar e presented. The support received by a liner from its host pipe is seen to be a function of the thickness of the liner, with thinner liners receiving more support. The nature of this support is described in terms of contact f orces and areas. The stress evolution is quantified by decomposing the stre ss at the critical point into flexural and compressive components. Ratios o f flexural stress to compressive stress greater than two indicate the domin ance of flexural stresses and suggest that flexural properties may be most appropriate when designing liners to resist buckling. Likewise, stress rati os less than two suggest that compressive properties may be most appropriat e. Flexural to compressive stress ratios are seen to increase with increasi ng host pipe ovality, gap between the liner and host pipe, longitudinal imp erfections, and applied pressure. (C) 2001 Elsevier Science Ltd. All rights reserved.