Research on the internal pressure behavior of metal gas distribution pipelines with different types of tubing defects

The paper aims to approach an important subject related to natural gas distribution networks which, depending on the expansion of the localities, are composed of intercommunicating pipes, pressure reducing stations and branch connections fittings. The urban networks are the most complex ones and the rural areas networks are the simplest. However, irrespective of their installation, they must meet the safety operating requirements as much as possible. According to standards, all these components must be tight and pressure resistant. In this regard, we intend to approach a very important issue related to the behavior of the tubular steel material showing corrosion and/or material defects, and to the internal stress caused by the gas pressure on the walls of the tubing material

Proceedings of the 2015 International Conference on Sustainable Energy and Environmental Engineering

The present paper aims at monitoring the behavior of the high density polyethylene pipe when pressed by an external force in order to shut it off so that the natural gas can no longer pass through the distribution pipelines. The behavior of the polyethylene pipe will be observed by means of fast shutter cameras, and the mechanical tests will be conducted by using the squeeze-off tool. Keywords-mechanical test; polyethylene pipe; rapid photograph

Experimental Research on the Behaviour of Metal Active Gas Tailor Welded Blanks during Single Point Incremental Forming Process

The present paper aims to study the behaviour of Metal Active Gas (MAG) tailor welded blanks during the single point incremental forming process (SPIF) from an experimental point of view. The single point incremental forming process was chosen for manufacturing truncated cone and truncated pyramid shaped parts. The same material (S355) and the same thickness (0.9 mm) were selected for the joining of blank sheets because the main goal of the paper was to study the influence of the MAG welding process throughout the SPIF process. A Kuka robot, equipped with a force transducer and an optical measurement system were used for manufacturing and evaluating the parts by SPIF. The selected output data were major and minor strain, thickness reduction, forces and springback at the SPIF process. Another line test was performed to evaluate the formability in SPIF. The main conclusion of the paper is that during the SPIF process, fractures occur in one side welded blanks even at moderate wall angles, while in the case of double side welded blanks there is a decrease of formability but parts can still be produced at moderate angles (55 degrees) without any problems

Minimizing the Main Strains and Thickness Reduction in the Single Point Incremental Forming Process of Polyamide and High-Density Polyethylene Sheets

Polymeric materials are increasingly used in the automotive industry, aeronautics, medical device industry, etc. due to their advantage of providing good mechanical strength at low weight. The incremental forming process for polymeric materials is gaining increasing importance because of the advantages it offers: relatively complex parts can be produced at minimum cost without the need for complex and expensive dies. Knowing the main strains and especially the thickness reduction is particularly important as it directly contributes to the mechanical strength of the processed parts, including in operation. For the design of experiments, the Taguchi method was chosen, with an L18 orthogonal array obtained by varying the material on two levels (polyamide and polyethylene) and the other three parameters on three levels: punch diameter (6 mm, 8 mm and 10 mm), wall angle (50°, 55° and 60°) and step down (0.5 mm, 0.75 mm and 1 mm). The output parameters were strain in the x direction, strain in the y direction, major strain, minor strain, shear angle and thickness reduction. Two analyses were conducted: signal-to-noise ratio analysis with the smaller-is-better condition and analysis of variance. The optimum values for which the thickness was reduced were the following: wall angle of 50°, punch diameter of 10 mm and step down of 0.75 mm