-
Intelligent Control Mechanism for Underwater Wet Welding
Joshua Emuejevoke Omajene,
Paul Kah,
Huapeng Wu,
Jukka Martikainen,
Christopher Okechukwu Izelu
Issue:
Volume 3, Issue 4, August 2015
Pages:
50-56
Received:
1 July 2015
Accepted:
10 July 2015
Published:
21 July 2015
Abstract: It is important to achieve high quality weld in underwater welding as it is vital to the integrity of the structures used in the offshore environment. Due to the difficulty in ensuring sound welds as it relates to the weld bead geometry, it is important to have a robust control mechanism that can meet this need. This work is aimed at designing a control mechanism for underwater wet welding which can control the welding process to ensure the desired weld bead geometry is achieved. Obtaining optimal bead width, penetration and reinforcement are essential parameters for the desired bead geometry. The method used in this study is the use of a control system that utilizes a combination of fuzzy and PID controller in controlling flux cored arc welding process. The outcome will ensure that optimal weld bead geometry is achieved as welding is being carried out at different water depth in the offshore environment. The result for the hybrid fuzzy-PID gives a satisfactory outcome of overshoot, rise time and steady error. This will lead to a robust welding system for oil and gas companies and other companies that carry out repair welding or construction welding in the offshore.
Abstract: It is important to achieve high quality weld in underwater welding as it is vital to the integrity of the structures used in the offshore environment. Due to the difficulty in ensuring sound welds as it relates to the weld bead geometry, it is important to have a robust control mechanism that can meet this need. This work is aimed at designing a co...
Show More
-
UREAD Impact Behaviour Using Silicon Based Materials
Remi Bouttier,
Gabriel Lopes,
Luke Clarke,
Rocco Lupoi
Issue:
Volume 3, Issue 4, August 2015
Pages:
57-62
Received:
3 June 2015
Accepted:
16 July 2015
Published:
28 July 2015
Abstract: Several methodologies and techniques are currently available so as to dissipate energy in engineering systems; most of them are either not re-usable, or complex in mechanism. This paper introduces an innovative re-usable energy absorption device, based upon the working principles of Equal Channel Angular Extrusion, and known as UREAD (Universal Re-usable Energy Absorption Device). This study compares the behaviour of different “low-density” deformable materials (a range of silicon rubber grades) inserted in a UREAD unit and loaded under impact condition. The energy absorbed was experimentally measured and compared against the impact energy. It was possible to dissipate levels as high as 74.91% of the impact energy when using a simple set-up, and the device re-usability was demonstrated.
Abstract: Several methodologies and techniques are currently available so as to dissipate energy in engineering systems; most of them are either not re-usable, or complex in mechanism. This paper introduces an innovative re-usable energy absorption device, based upon the working principles of Equal Channel Angular Extrusion, and known as UREAD (Universal Re-...
Show More
-
Highly Turbulent Flow Laminarized by Hairy Pipe Walls
Bo Anders Nordell,
Ragnar Oskar Gawelin
Issue:
Volume 3, Issue 4, August 2015
Pages:
63-70
Received:
30 June 2015
Accepted:
18 July 2015
Published:
28 July 2015
Abstract: Nature has found ways to laminarize turbulent flows, as demonstrated by the high swim speed of dolphins and the silent flight of owls. Owls locate their prey by hearing and need to fly silently. In both cases it has something to do with the soft pliable surface of the moving body and the wavy pattern that occurs on the dolphin skin and the owl feathers. Our objective was to investigate whether a pipe lined with a hairy soft carpet would “laminarize” air flows. The degree of laminarization was determined by the velocity profile. Manual pressure measurements were done to determine the air velocity at cross-sections along the pipe. Varying flow rates were tested before the hair was cut increasingly shorter. It was found that for some hair lengths the velocity profile approached the parabolic form of laminar flow at very high Reynolds number.
Abstract: Nature has found ways to laminarize turbulent flows, as demonstrated by the high swim speed of dolphins and the silent flight of owls. Owls locate their prey by hearing and need to fly silently. In both cases it has something to do with the soft pliable surface of the moving body and the wavy pattern that occurs on the dolphin skin and the owl feat...
Show More
-
Stress Analysis of Gun Barrel Subjected to Dynamic Pressure
H. Babaei,
M. Malakzadeh,
H. Asgari
Issue:
Volume 3, Issue 4, August 2015
Pages:
71-80
Received:
5 May 2015
Accepted:
2 July 2015
Published:
1 August 2015
Abstract: In the optimal design of a modern gun barrel, there are some aspects to be considered. One of the main factor is internal ballistic which consist of pressure-time, pressure-distance, velocity-time and distance-time curves. In this paper, a simple analytical solution for the plastic stress of an internally pressurized open-ended thick-walled cylinder made of hardening steel which is the closest model to gun barrel is obtained in perfectly plastic and plane stress condition by using energy method and the yield criterion of Von Mises and adding rifle grooves and choosing stress components as basic unknowns and ballistic pressure equation as known. Then results of analytical solution are compared to a numerical model and verified a very well and reliable accuracy. So the resultant can be used easily in calculation of radial expansion velocity and compressive pressure.
Abstract: In the optimal design of a modern gun barrel, there are some aspects to be considered. One of the main factor is internal ballistic which consist of pressure-time, pressure-distance, velocity-time and distance-time curves. In this paper, a simple analytical solution for the plastic stress of an internally pressurized open-ended thick-walled cylinde...
Show More
