Analysis of Symmetrical and Nonsymmetrical Vertical Expansion Loop to Increase Flexibility And Reduce Pipe Stress Based On ASME B31.3

Thepiping system is a medium used to convey, distribute, mix, separate, discharge, meter, control or snub fluid flows, and transmit a fluid pressure. The piping system design will have stresses due to thermal and pressure effect. The thermal effect induce pipe expansion. The pipe expansion affect to pipe flexibility, so it is necessary to design an expansion loop. Expansion loop is a method used to increase flexibility in piping systems. This article aims to analyze symmetrical and non-symmetrical in vertical expansion loops whether it can increase flexibility and reduce pipe stress. This article conducts an expansion loop design with 3 trials, namely trial 1 (Vertical Expansion Loop), trial 2 (Nonsymmetrical Vertical Expansion Loop 1), and trial 3 (Nonsymmetrical Vertical Expansion Loop 2). The three trials were compared for flexibility and stress values based on ASME B31.3 requirements. The study results show that all trial 1, trial 2, and trial 3 have good flexibility with a value of 0.00016 because not exceed the requirements of ASME B31.3. The highest design code stress value in trial 1 is 5955 psi (Node A07F), trial 2 is 5906 psi (Node A05F), and trial 3 is 5906 psi (Node A06N). All trials have a code stress not exceeding the allowable stress (20000 psi). So that the symmetrical or nonsymmetrical design of the vertical expansion loop can both increase flexibility and reduce pipe stress.

Development of 3D FE Models for Incremental Forming Process Analysis of UOE Linepipes

Three dimensional (3D) FE models have been developed for simulation of the incremental forming processes employed in UOE linepipe manufacturing at Tata Steel Hartlepool 42” Pipe Mill, namely edge crimping (C-press) and pipe expansion (expander). Transitional zone behaviour resulted from both forming operations as previously identified in practice has been revealed, for the first time, by the 3D FE simulations and preliminarily analysed. It was demonstrated that the transitional zone features observed in both edge crimping and pipe expansion were initiated in the plate/pipe feed-in side/area of the dies, and then formed within the working length/face of the forming dies. Detailed examination and analysis of the FE results, in terms of plastic strain and residual stress patterns as well as contact pressure distributions, have shown that the initiation of the transitional zone features was due to the redundant plastic deformation caused by (cantilever) bending in the material feed-in area of the dies mainly along the longitudinal direction. It is therefore believed that minimisation/elimination of such redundant plastic bending effect in the longitudinal direction would lead to minimisation/elimination of the unfavourable deformation features in the so-called transitional zones, which could be achieved through improved die designs and possibly forming process parameter settings.

Effect of pipe expansion on the redistribution of residual stresses after molding

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

Design of an Experimental Device for Simulation of Pipeline Expansion

This article describes the design of an experimental device for simulating pipe expansion. The device consisted of various variants of compensating elements and types of piping materials. Based on this, a 3D model was developed, together with numerical design calculations of compensators. Subsequently, a more complex analysis was performed by using the CAE Pipe calculation program, which performed calculations of dilatations, forces at fixed points and stresses in the pipeline.