SADDLE-SUPPORTED PIPELINES - INFLUENCE OF UNILATERAL SUPPORT AND THICKNESS ON THE STRESS STATE

The present paper deals with the sensitivity analysis of above-ground pipelines under static loading, by taking into account the possibility of development of uplift at the pipe/saddle interfaces. Applying clas sical frictionless unilateral contact to describe mathematically the p ipeline support conditions and an appropriate finite element scheme, t he discrete problem is put in the form of an inequality restrained qua dratic optimization problem with respect to either displacements or st resses. In order to investigate the structural response of an above-gr ound pipeline with respect to the variation of critical design paramet ers (cf e.g. the thickness), the sensitivity analysis problem has been formulated: the latter is a quadratic programming problem with design parameters appearing only in the quadratic term. This problem is trea ted numerically by means of appropriate quadratic optimization techniq ues. The effectiveness of the method proposed is illustrated by means of a numerical application.