A validated thermal model of bead-on-plate welding

In this paper, finite element model is used to carry out thermal analysis of bead-on-plate welding. The model followed the proposed five step strategies which were then built into a model to obtain temperature history at the positions of thermocouples. Temperature field was also evaluated by comparing predicted weld bead with the actual weld bead. Using these proposed strategies, well matched temperature histories and temperature field have been obtained

Evaluating the effect of the pin's length to the strength of double sides friction stir welded aluminum

Based on previous research, it is believed that the double side friction stir welding will improve the obtained joint. It is hoped the length of the pin broaden the strain hardened area (especially the interference zone) which in turn will produce the stronger joints. From tensile test data, the tensile strength does increase by the length of the pin. The maximum tensile strength of 183 MPa acquired from the 6.5 millimeter pin which is equal to 75% joint efficiency whilst the lowest is 42 MPa resulted by the 2.5 millimeter pin. The hardness test confirmed the existing of the strain hardening phenomenon, which was shown by harder materials at interference zone. Other supporting evidence is the micro structure photo. The photos showed that not only exhibits strain hardening the interference zone also yields finer dispersed micro structure that will provide stronger joint

Deformation Mode and Energy Absorption Analysis of Bi-Tubular Corrugated Crash Box Structure

In this research, the characteristic of crash box with bi-tubular corrugated structure are numerically examined under axial loading condition. The crash box characteristic were observed in the compression test of aluminum alloy (AA6061) using ANSYS software. The comparation were carried out on two geometrical types, namely: ordinary corrugated tube (OCT) and bi-tubular corrugated tube (BCT). The result showed that comparing both of crash box structure exhibit the Simultaneous crush mode (S-mode) deformation. The force-displacement present a stable diagram without any fluctuation. BCT structure resulted 71% energy absorption capacity increment compared to OCT structure. The highest energy absorbed by BCT structure was 10.8 kJ. There are no significant specific energy absorption different between the specimen and the highest SEA occur at OCT structure with 31.281 kJ kg-1

Bio-Komposit Hybrid yang Memiliki Unjuk Kerja Maksimal pada Beban Fatik dengan Stress Ratio R = -1

Komposit dengan bahan dasar alami atau dikenal dengan nama bio-komposit akhir-akhir ini mulai banyak dikembangkan selain disebabkan tinjauan ekologis yakni material bio-komposit lebih ramah lingkungan juga disebabkan harganya yang murah dan untuk beberapa bahan alami memiliki kekuatan yang tidak kalah dibandingkan dengan bahan sintetis. Pada penelitian ini komposit menggunakan bahan pengisi serat kenaf dan serbuk kayu dengan matrik poliester 157 BQTN-EX. Kenaf diharapkan yang berupa serat diharapkan memberikan unjuk kerja yang baik beban tarik dan kayu dalam bentuk serbuk diharapkan memberikan unjuk kerja yang baik ketika menerima beban tekan. Komposisi serat kenaf dan serbuk kayu divariasikan dan dicampur bersama matrik polyester dan zat pengaktif kemudian dituang kedalam cetakan dengan cara diinjeksikan. Hasil cetakan berupa spesimen tarik, spesimen impak dan spesimen tekan kemudian diuji untuk mengetahu unjuk kerja dari komposit. Hasil uji sifat mekanik komposit menunjukkan bahwa serat kenaf memiliki unjuk kerja yang lebih baik dibanding serbuk kayu. Berdasar hasil dari uji impak dapat disimpulkan bahwa perbandingan komposisi serat kenaf dengan serbuk kayu tidak menunjukkan perbedaan. Hal ini disebabkan pada uji impak terdapat campuran bagian yang mengalami tarikan dimana serat kenaf akan menunjukkan kelebihannya dan bagian yang mengalami tekanan dimana serbuk kayu menunjukkan kelebihannya

Analisis Penyerapan Energi Dan Pola Deformasi Crash Box Dengan Variasi Sudut Tirus Dinding Crash Box Pada Uji Simulasi Tabrakan Arah Frontal

Sistem transportasi merupakan salah satu kebutuhan yang penting untuk dipenuhi dalam mempermudah kehidupan pada zaman modern ini. Di sisi lain, meningkatnya kebutuhan akan hal tersebut juga akan ikut meningkatkan produksi kendaraan yang secara tidak langsung turut meningkatkan jumlah kecelakaan. Meninjau hal tersebut, standar keselamatan kendaraan yang lebih baik sangat dibutuhkan, salah satunya adalah crash box. Crash box merupakan sistem keamanan pasif yang digunakan untuk mengurangi tingkat keparahan kecelakaan yang dialami penumpang atau bagian kendaraan yang vital akibat tabrakan. Penelitian ini meninjau pengaruh variasi sudut tirus dinding crash box berpenampang lingkaran (circular) terhadap pola deformasi dan penyerapan energi pada uji simulasi tabrakan arah frontal. Penelitian dilakukan dengan software berbasis metode elemen hingga (MEH). Variasi yang digunakan dalam penelitian ini yaitu crash box dengan sudut tirus (α) 0,2°; 0,4°; 0,6°; 0,8; dan 1,0° dengan material crash box baja AISI 1340. Dari hasil penelitian diperoleh bahwa pola deformasi yang terbentuk adalah pola aksial dengan mode concertina dan campuran (concertina + diamond). Deformasi mode campuran terjadi pada crash box t a 1,6 α 0,0°; α 0,8°; α 1,0°. Penyerapan energi meningkat seiring bertambah besarnya sudut tirus dinding crash box, dengan kemampuan menyerap energi terbesar pada crash box dengan sudut tirus (α) 1,0° sebesar 10823 J. Semakin besarnya sudut tirus dinding crash box juga menunjukkan peningkatan penyerapan energi spesifik crash box

Comparison of Corner-Butt 45 (Cb-45) and Corner-Lap (Cl) joints in friction stir welding

The 10 mm thick Aluminum 6061 plates have been corner joined using varied design and those were 45ᴼ Corner Butt and Corner Lap Joints (CB-45 & CL). Friction tool was hardened EMS 45. True experimental method was used with independent parameters is feed rate which varied at 10 mm/min, 15 mm/min and 30 mm/min respectively. Other parameter such as rotating speed was kept constant. Experiment results show that, CB-45 yields better properties than CL. The tensile strength of CB-45 reaches 163.7 MPa for 10 mm/min feed rate. Whilst CL produces joint with tensile strength equal 120 MPa for equal parameters. Microstructure observation showed that CB-45 produces fine and homogenous appearance of MgO compared to CL. This phenomenon is caused by the pin of CB-45 joint which fully penetrates the nugget zone which is not found in CL design. This microstructure in turn promotes higher tensile strength of CB-45

The Effect of Fiber Orientation and Stress Ratio on the Crack Growth Behavior of Fiber Metal Laminates (FMLs)

The crack growth behavior of fiber metal laminates (FMLs) with fiber orientations of 90°/0° and 45°/45° to load direction was investigated with varying stress ratios of the cyclic constant load. The study shows that crack growth behavior depends on the conditions of the cyclic load and the orientation of the fiberglass orientation. A higher stress ratio of the cyclic constant load causes fatigue life to decrease, and is associated with stress concentration just in front of the crack tip. The stress concentration in the FMLs with 45o/45o fiberglass orientation is higher than that of 90o/0o, which means the fatigue life in the former is shorter. The bridging of the fiber-epoxy composite takes place when the stress ratio of the constant cyclic load is lower than 0.4, which also enhances fatigue life