Experimental and Numerical Investigation of Pressurized Pipe Elbows Under Strong Cyclic Loading

Abstract

The present work examines the behavior of pipe elbows subjected to strong cyclic in-plane bending loading in the presence of internal pressure. In the first part of this work the experimental procedure is presented in detail. The tests are conducted in a constant amplitude displacement-controlled mode resulting to failures in the low-cycle fatigue range. The overall behavior of each tested specimen, as well as the evolution and concentration of local strains are monitored throughout the testing procedure. Different internal pressure levels are used in order to examine their effect on the fatigue life of the specimens. The above experimental investigation is supported by rigorous finite element analysis. Using detailed dimensional measurements and material testing obtained prior to specimen testing, detailed numerical models are developed to simulate the conducted experiments. An advanced cyclic plasticity material model is employed for the simulation of the tests. Emphasis is given on the local strain development at the critical part of the elbow where cracking occurs. Finally, the results of the present investigation are compared with available design provisions in terms of both ultimate capacity and low-cycle fatigue.

Validation on large scale tests of a new hardening–softening law for the Barcelona plastic damage model

“…Under extreme loading conditions, such as the high repeated incursions in the nonlinear zone that the imposed displacement in this case causes, elbows exhibit two different failure modes. These are either significant cross-sectional ovalization or local buckling, as reported by the experimental work described in Sobel and Newman [23], [24], Dhalla [25] and Greenstreet [26], Tan et al [27], Shalaby and Younan [28] and Suzuki and Nasu [29] for monotonic bending moments and Yahiaoui et al [30], Slagis [31] and Fujiwaka et al [32] for cyclic loading, and from the work of Karamanos et al [33], [34], Pappa et al [35], Varelis et al [36], [37].…”

An Experimental Study on Seismic Performance Evaluation of Multi-Ply Bellows Type Expansion Joint for Piping Systems

“…Research on piping that is installed in structures has also been conducted in various industrial fields. Experimental studies were conducted to analyze the nonlinear behavior of piping elements under internal pressure and seismic loading conditions [14,15], and the low-cycle fatigue and limit state of the piping system was defined in these studies [16][17][18][19][20][21]. A program was also performed to analyze the gap between plastic collapse corresponding to the design standard consideration and leakage related to the actual failure observed through experimental tests and to simulate the extreme nonlinear behavior of piping [22].…”

Numerical simulation of steel member response under strong cyclic loading

“…The elbow experiments conducted in the course of INDUSE project [Karamanos (2013)] are presented extensively in Varelis et al (2013aVarelis et al ( , 2013b.…”