0

Newest Issue


Research Papers: Design and Analysis

J. Pressure Vessel Technol. 2017;139(4):041201-041201-12. doi:10.1115/1.4035935.

In this study, two failure modes, yield buckling of the compression ring section and strength failure in the roof-to-shell of the tank, have been proposed for a vertical vaulted tank. The failure criteria of the two failure modes in the roof-to-shell of vault tanks are established via finite element analysis of three tanks of 640 m3, 3200 m3, and 6800 m3 in volume. The finite element models are built with axisymmetric elements and spatial multi-elements. Based on the strength failure criterion, the failure pressure formula in the vaulted tank roof-to-shell is derived. The maximum relative error between the theoretical calculation and numerical simulation is 9.7%. Finally, we verify the strength failure criterion through a tank failure test; the maximum relative error between the test and theoretical calculation is 9.6%. The failure pressure of both failure modes has been compared and analyzed. The failure pressure of the yield buckling in the compression ring section is about 1.65 times that of the strength failure in the roof-to-shell of the tank.

Commentary by Dr. Valentin Fuster

Research Papers: Fluid-Structure Interaction

J. Pressure Vessel Technol. 2017;139(4):041301-041301-9. doi:10.1115/1.4035464.

A new cellular automaton technique was developed based on the finite difference scheme to analyze structures such as beams and plates as well as the acoustic wave equation. The technique uses rules for a cell, and the rules are applied to all the cells repeatedly. The technique is very easy to write a computer code and computationally efficient. Like the standard cellular automaton, many different boundary conditions can be applied easily to the new technique. The technique was applied to both structural and fluid–structure interaction problems. The fluid domain was modeled as either the acoustic medium without flow using the newly developed cellular automaton rules or the fluid flow medium using the lattice Boltzmann technique. Multiple example problems were presented to demonstrate the new technique. Those included dynamic analyses of beams and plates, acoustic wave problems, and coupled fluid–structure interaction problems.

Commentary by Dr. Valentin Fuster

Research Papers: Materials and Fabrication

J. Pressure Vessel Technol. 2017;139(4):041401-041401-8. doi:10.1115/1.4035884.

This research investigated the effects of global (in other words, furnace-based) and local post weld heat treatment (PWHT) on residual stress (RS) relaxation in API 5L X65 pipe girth welds. All pipe spools were fabricated using identical pipeline production procedures for manufacturing multipass narrow gap welds. Nondestructive neutron diffraction (ND) strain scanning was carried out on girth welded pipe spools and strain-free comb samples for the determination of the lattice spacing. All residual stress measurements were carried out at the KOWARI strain scanning instrument at the Australian Nuclear Science and Technology Organization (ANSTO). Residual stresses were measured on two pipe spools in as-welded condition and two pipe spools after local and furnace PWHT. Measurements were conducted through the thickness in the weld material and adjacent parent metal starting from the weld toes. Besides, three line-scans along pipe length were made 3 mm below outer surface, at pipe wall midthickness, and 3 mm above the inner surface. PWHT was carried out for stress relief; one pipe was conventionally heat treated entirely in an enclosed furnace, and the other was locally heated by a flexible ceramic heating pad. Residual stresses measured after PWHT were at exactly the same locations as those in as-welded condition. Residual stress states of the pipe spools in as-welded condition and after PWHT were compared, and the results were presented in full stress maps. Additionally, through-thickness residual stress profiles and the results of one line scan (3 mm below outer surface) were compared with the respective residual stress profiles advised in British Standard BS 7910 “Guide to methods for assessing the acceptability of flaws in metallic structures” and the UK nuclear industry's R6 procedure. The residual stress profiles in as-welded condition were similar. With the given parameters, local PWHT has effectively reduced residual stresses in the pipe spool to such a level that it prompted the thought that local PWHT can be considered a substitute for global PWHT.

Commentary by Dr. Valentin Fuster
J. Pressure Vessel Technol. 2017;139(4):041402-041402-8. doi:10.1115/1.4035976.

In this study, fatigue performances of the vehicle toroidal liquefied petroleum gas (LPG) fuel tanks were examined to estimate the fatigue life and its failure locations using both experimental and finite element analysis (FEA) methods. The experimental investigations performed as accelerated fatigue tests were carried out using a hydraulics test unit in which the tanks were internally pressurized by hydraulic oil. The LPG tanks were subjected to repeated cyclic pressure load varying from zero to service pressure (SP) of the tank. The computerized FEA modeling of these tanks were developed in three-dimensional (3D) form using nonuniform geometrical parameters and nonlinear material properties. These models were also subjected to zero-based high cycle fatigue pressure load considering the stress life approach. The FEA modeling process was also simulated in nonhomogeneous material conditions. Therefore, the fatigue life performance and failure location of the toroidal LPG fuel tanks were predicted using the computer-aided simulations and compared with the experimental results.

Commentary by Dr. Valentin Fuster

Research Papers: Operations, Applications and Components

J. Pressure Vessel Technol. 2017;139(4):041601-041601-9. doi:10.1115/1.4035979.

A three-way water hydraulic pressure reducing valve (PRV) was developed in this paper for a test equipment in laboratory for adapting complex conditions. The designed PRV has a damping chamber with an orifice located at the spring chamber. Two types of throttles and orifice diameter were investigated through dynamic simulation and optimization, and their dimensions were determined and applied to the manufactured valve prototype. The static and dynamic performances of the valve were tested by experiments. At the preset pressure of 5.0 MPa, the outlet pressure variations for the pressure-reducing port and the relief port, are 0.73 MPa and 1.44 MPa, respectively, while the flow variation is up to 18.0 l/min. The experimental rising times and settling times of the PRV under the inlet pressure step for preset pressures of 5.0 MPa are 33.7 ms and 120.2 ms, respectively, and the overshoot is 3.76%. The test results at each preset pressure agree well with the simulation which verifies that the simulation model can be used to predict the dynamic performance of the PRV. The experimental results for the valve under flow step input conclude that it can work stably at small flow state. The research indicates that making the spring chamber a damping chamber by using an orifice is a feasible way to increase the pressure stability and the dynamic performance of the PRV. However, the damping effect of this structure is insufficient at high working pressure.

Commentary by Dr. Valentin Fuster

Technical Brief

J. Pressure Vessel Technol. 2017;139(4):044501-044501-3. doi:10.1115/1.4035975.

This note is concerned with two circular-hole cracks of the same size in an infinite plate in tension by means of the generation of Bueckner's principle and the hybrid displacement discontinuity method. Many numerical results which can reveal the interactions of two circular-hole cracks are given.

Commentary by Dr. Valentin Fuster
J. Pressure Vessel Technol. 2017;139(4):044502-044502-4. doi:10.1115/1.4035978.

Casing and tubing is widely used as protective conduits during all the phases of operations and productions for the oil and gas industry. Recently, casing and tubing burst failure accidents often take place in high pressure and high temperature (HPHT) oil and gas wells during production. Therefore, it is very important to accurately predict casing and tubing bust strength in the casing and tubing design and operation process. PD CEN ISO-TR 10400 presents the ductile rupture model for capped-end conditions, but capped-end casing and tubing applied in oil fields is few. For this case, this document establishes the ductile rupture model for capped-open conditions under combined loads on the base of PD CEN ISO-TR 10400. Numerical and experimental comparisons show that the ductile rupture model for capped-open conditions under combined loads prediction values essentially coincides with burst data provided by PD CEN ISO-TR 10400.

Topics: Stress , Rupture , Pressure , Tubing , Design
Commentary by Dr. Valentin Fuster

Discussion

J. Pressure Vessel Technol. 2017;139(4):045501-045501-1. doi:10.1115/1.4034878.

In the paper by Moustafa et al. (2012, “Leak Localization in Pipelines Via Computational Pipeline Monitoring,” ASME J. Pressure Vessel Technol., 134(4), p. 041701), they have described a scanning procedure to locate multiple leaks in a pipeline by software, which is equivalent to an optimization procedure looking for the nodes in the spacial discretization model of the fluid. The purpose of this correspondence is to make comments and remarks about it.

Commentary by Dr. Valentin Fuster

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In