Achmad Zubaydi

Effect of Tool Tilt Angle and Tool Plunge Depth on Mechanical Properties of Friction Stir Welded AA 5083 Joints

The influences of tool tilt angle and tool plunge depth on tensile properties of friction stir welded AA 5083-H116 with the thickness of 4 mm were studied. Four different values of tool tilt angle of 1΀ 2°, 3°, and 4° were used to fabricate the joints. The tool plunge depths were choosen 3.85 mm, 3.90 mm and 3.95 mm. The FSW rotational speed and welding speed were 1125 rpm and 30 mm/min, respectively. The temperature, macrostructure, hardness and tensile strength of joints were compared and discussed. Results show that the increase of tool tilt angle and tool plunge depth resulted the welding temperature increase. Due to the increase of welding temperature, the hole defect become smaller. Tensile testing results indicated that the tensile strength of joints increased with increasing both the tool tilt angle and tool plunge depth.

Analysis of the Adhesiveness and Glue Type Selection in Manufacturing of Bamboo Laminate Composite for Fishing Boat Building Material

The purpose of this study is to select the appropriate high quality-strong-durable type of glue for bamboo laminated composite to substitute Teak wood as an alternative material for fishing boat construction. Tape Test and Pull Off Test according to ASTM D3359 and ASTM D4541 are applied on substrates of Betung laminated bamboo (Dendrocalamus Asper species) in order to determine the strength level of adhesiveness. Four types of glue are applied to bamboo laminated substrate. Having analyzed the experiment results, it indicates that Epoxy Polyamide has the highest adhesion value comparing to others. The Tape Test grades for Epoxy Polyamide are 5A (no glue peeling) and 5B (0% glue chipped extension) as well as the score of Pull Off Test is 7.92 MPa. In terms of construction cost for building fishing boat 20GT (laminated bamboo) using epoxy polyamide is a half compared to Teak wood material.

Finite Element Analysis of Ship Deck Sandwich Panel

Recently various types of sandwich panel are applied for constructing bridge and ship structures. Sandwich panel is material that consists of lightweight core material and two metal faceplates. The application of sandwich panel in ship structures makes the structure less-complex and ship’s selfweight lighter because of the reduction of secondary stiffeners. This paper discusses sandwich panel that was fabricated using synthetic resin core material and two steel faceplates. This study is aimed to analyze stresses developed in the sandwich panel of 750 GT Ro-Ro ship car deck structure when it was subjected to the deck design load. The finite element analysis was carried out to obtain the stress distribution and maximum deformation on the car deck structures. The stress of the ship car deck constructed using conventional steel structure, i.e. steel plate and stiffener, was compared with the stress of the deck that was built using sandwich panel.

Effect of Backplate Thermal Diffusivity on Mechanical Properties of Double Sided Friction Stir Welded Aluminum for Ship Structure

The effects of backplate thermal diffusivity on mechanical properties of friction stir welded (FSW) aluminum alloy 5083 joints were studied in the present work. Three variation of backplate material, marble-block, mild steel and aluminum which represent low, medium and high diffusivity respectively, were used in the welding processes. The results showed that the increase of backplate thermal diffusivity resulted the decrease of the welding temperature. Defect free weld was obtained if backplate material was mild steel, whereas the other backplate material, marble-block and aluminum were obtained defect welds. The highest tensile strength as well as microhardness were obtained in the mild steel backplate.

Effect of Weld Side Combination on Mechanical Properties of Double Sided Friction Stir Welded 5083 Aluminum Alloy

Double sided friction stir butt welds on 6 mm thick of 5083 aluminum alloy were produced. Two variants of the weld side combination, different weld side (DS) and same weld side (SS), have been made to investigate the effect of the weld side on mechanical properties.The SS is a double sided welding process that produces advancing side in one plate and retreating side in the other one. On the other hand, the DS is a double sided welding process that causes advancing side and retreating side in each plate. Tensile properties of the joints were evaluated and correlated with macrostructure and hardness. The weld side influenced the macrostructure and mechanical properties of welded joints. The different weld side (DS) had better mechanical properties than the same weld side (SS).