Mohd Afendi Rojan

An Effective Jig for Friction Stir Welding of Pipe Butt Joint

A dedicated or specialized friction stir welding (FSW) machine is quite costly especially for pipe joining. Therefore, not many institutions manage to conduct their research on FSW at their facilities. Besides that, the difficulty to design a jig that can hold the complex shape such as pipe section tightly and easily to be removed during and after the FSW process respectively will nullify the intentions. In many institutions, there was either conventional or CNC milling machine available in their workshops. Thus, a jig called orbital clamping unit (OCU) was designed to suit this milling machine. It acts as an additional device to enable this milling machine to run as FSW machine at a lower cost, hence fully utilized the available facility in the workshop. Several good samples were successfully produced by using this jig and milling machine

The Effect of Loading Mode on Fracture Toughness of Arcan Adhesive Joint

This paper presents the experimental investigation on adhesive joint under three loading angles using a modified Arcan jig. Fracture test was performed using the fabricated Arcan specimens and Araldite adhesive with loading angle of 0°, 90° and 45° to represent Mode I, Mode II and mixed Mode loading, respectively. Eighteen specimens were prepared with adhesive thickness of 6 mm and nine of them with interface crack length of 5 mm. The result shows the stress intensity factor, K is influenced by the loading angle and the initial crack-line directions. KI was found greater than KII .

Influence of Tool Plunge Depth on the Joint Strength and Hardness of Friction Stir Welded AA6061 and Mild Steel

The purpose of this paper is to investigate the impact of the tool plunge depth on the mechanical properties of friction stir welding (FSW) of AA6061 and mild steel. In FSW, welding is performed using a non-consumable rotating tool that is allowed to plunge in between two plates in a butt joint and travel along the abutting line. The tool plunge depth determines how deep the pin and shoulder of the tool penetrates the surface of the plates. Tensile testing was performed to determine the influence of plunge depth at different tool travel speeds on joint failure strength. Also, the formation of defects and its relationship with plunge depth were also investigated. Vickers microhardness testing was also done on weld cross sections to study plunge depth’s effect on hardness.

Tensile and Hardness Analysis of Dissimilar Friction Stir Welding Between AA6061 with AA5083 and Mild Steel

In this paper, the friction stir welding (FSW) technique was used to create dissimilar alloy joints of AA6061-AA5083, and dissimilar material joints of AA6061-S235JR mild steel. Joints were fabricated by a conventional belting milling machine. Plates of 5 mm thickness were welded in a butt joint configuration. The joints were evaluated by extracting tensile testing specimens to study the failure strength at different rotational speeds. Tunnel defects were formed under certain parameters and changing the parameter values had different effects on the tunnel defects depending on the type of dissimilar joint welded. Vickers micro hardness measurements were taken on cross sections of welded joints to study the hardness pattern across the weld zones.

Study of Eddy Current Density Distribution in a Contactless Breast Cancer Detection Mechanism Using Magnetic Induction Spectroscopy

Breast cancer is a throbbing disease that no longer needs an introduction. This is especially true among women due to their unique breast structure that naturally has more breast tissues compared to that of man’s. It is been forecasted that in 2015, a minimum of 60290 new cases of breast cancer will be reported. The goal of this study is to analytically evaluate the changes in the induced Eddy current densities as a function of di-electrical properties of the breast tissue with respect to tumor positioning as well as its size. This is achieved by running numerical simulations on the proposed mechanism of magnetic induction to detect tumors among healthy breast tissue via a 2D breast model configuration. The analytical results presented in this article, proved that the multi frequency magnetic induction principle is viable in detecting the breast lesions as small as 0.2 cm non-invasively through the distributions of the induced Eddy current density. While important pattern of the induced current were reflected when the tumors are located at the far ends of the breast diameter. The minimum results computational time with the proposed system is 10 s.

Convergence study of global meshing on enamel-cement-bracket finite element model

This paper presents on meshing convergence analysis of finite element (FE) model to simulate enamel-cement-bracket fracture. Three different materials used in this study involving interface fracture are concerned. Complex behavior ofinterface fracture due to stress concentration is the reason to have a well-constructed meshing strategy. In FE analysis, meshing size is a critical factor that influenced the accuracy and computational time of analysis. The convergence study meshing scheme involving critical area (CA) and non-critical area (NCA) to ensure an optimum meshing sizes are acquired for this FE model. For NCA meshing, the area of interest are at the back of enamel, bracket ligature groove and bracket wing. For CA meshing, area of interest are enamel area close to cement layer, the cement layer and bracket base. The value of constant NCA meshing tested are meshing size 1 and 0.4. The value constant CA meshing tested are 0.4 and 0.1. Manipulative variables are randomly selected and must abide the rule...

The Hardness Variation Due to Secondary Heating in Friction Stir Welding of Small Diameter Aluminium Alloy 6063 Pipe

Friction stir welding (FSW) is a solid state joining process which utilizes the frictional heat of a high speed rotating tool to soften the adjoining sections and stirred/joined them together as one part without filler. In the FSW of pipe joining, a tool rotating at high speeds will start and stop at the same point in order to complete full weld cycle. The FSW of a small diameter pipe can cause secondary heating to occur at the start and stop point. Several pipe samples of 89 mm outside the diameter were prepared based on several specified welding parameters at a stationary position and completed the weld cycle. The Bridgeport 2216 CNC Milling Machine and a customised orbital clamping unit (OCU) were fully utilized for the sample’s preparation. This present study analysed the variation in hardness due to secondary heating for a small pipe diameter. The hardness varies between 18.7 HRB minimum to 33.6 HRB maximum, yielding to lower value due to this condition.

REFLECTION AND DIELECTRIC MEASUREMENT FOR SALINITY OF WATER USING MICROSTRIP LOOP ANTENNA AND DIELECTRIC PROBE

This study was conducted to investigate the feasibility of loop antenna in gauging level of salinity of water via electromagnetic wave reflection. High salinity cause adverse effect to environment. When high levels salinity of water diffuse into soil, it declines values of land for human and animal consumption. These impacts can cause tremendous monetary lost because the restoration of impairments is extremely costly. Therefore, a reliable salinity detection system of water source is crucial. In this work, reflection measurement was conducted using loop antenna in conjunction with network analyser for water salinity detection. Dielectric probe will be then used for dielectric characterization due to different water salinity. It comes to learn that the different level of salinity of water exhibit different dielectric properties through reflection measurement. The increment of salinity leads to increment and decrement of dielectric constant and loss factor, respectively. Similar observation can be found in reflection coefficient.

The Effect of Pin Size on Friction Stir Welded AA508 3 Plate Lap Joint.

Tool geometry plays a major role in the weld quality of friction stir welded aluminum alloys. Because of lap joint, tool geometry must be designed specifically according to the thickness of the weld specimen. Therefore, in the present work, the effect of tool geometry will be analyzed for mechanical properties of aluminum alloy 5083 weld lap joint. The result of this research shows that aluminum alloy 5083 can be joined by the friction stir welding (FSW) process, using a tapered cylindrical design pin tool with a variety of diameters (i.e 5mm ,6mm, 7mm, 8mm and 9mm) and a fix 20 mm shoulder made of H13 Steel with varying rotational speeds (910 RPM, 1280 RPM and 1700 RPM). The investigation results show the relationship between the tool geometry and the rotation speed effect on mechanical properties of the welded joint.

The Effect of Rotational Speed on Weld Strength of Friction Stir Welded Butt Joint

The research work is carried out in order to achieve the following objectives which are to investigate the effect of different rotational speed on the weld quality of metal of aluminum alloy AA 5083 during FSW and to analyze the optimum rotational speed towards tensile property improvement. The rotational speed is important in producing the frictional heat to induce plasticized flow. The rotational speed determines tensile strength and quality weld surface. The result obtained for this research is based on tensile testing. The welding parameter involved such as welding speed (67mm/min), tilt angle (3⁰ ), tool shoulder diameter (40mm), tool pin type (Threaded Cylindrical) and variable rotational speed of 490rpm, 653rpm, 910rpm, 1280rpm, and 1700rpm by using universal milling machine milko 37.