MECHANICAL
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Analisis Dinamik Tabung Kontinu dengan Metode Beda Hingga
Full text linkStruktur tabung kontinu telah digunakan di berbagai struktur bangunan seperti tiang, pipa, tunnel dan jembatan. Dibutuhkan analisis dinamik untuk mengetahui perilaku struktur terhadap beban yang diterimanya. Proses analisis dimulai dengan memformulasikan persamaan gerak struktur tabung kontinu berdasarkan teori Euler-Bernoulli beam. Disediakan studi kasus berupa struktur tabung kontinu dengan tumpuan sederhana yang diberikan beban harmonik terpusat. Solusi analitik diperoleh melalui metode pemisahan variabel atau superposisi mode. Sebagai alternatif, dilakukan penyelesaian secara numerik menggunakan metode beda hingga tengah. Displacement yang diperoleh dari metode pemisahan variabel menunjukkan hasil yang eksak. Metode beda hingga tengah menghasilkan hasil yang mendekati solusi analitik. Akurasi dari metode beda hingga sangat dipengaruhi oleh jarak grid dan langkah waktu .
Kajian Potensi dan Pengembangan Turbin Angin Daerah Urban
Full text linkPada wilayah perkotaan atau wilayah urban turbin angin dapat diintregasikan pada bangunan atau disebut building integrated wind turbine. Disisi lain, pola angin pada daerah urban bersifat turbulen dan memiliki masalah lebih kompleks, Karakteristik angin suatu wilayah berbeda, hal ini dipengaruhi oleh kondisi permukaan tanah. Kondisi nilai roughness length yang tinggi seperti daerah perkotaan menimbulkan zona turbulen yang besar, selain itu pada saat bersamaan angin menumbuk bangunan dan obyek lain akan menimbulkan profil pusaran angin. Kajian studi ini membahas tentang karakteristik angin serta kelayakan potensi penerapan turbin angin pada daerah perkotaan atau urban. Tujuan studi ini dilakukan untuk membahas fenomena dan potensi angin pada daerah urban serta me-review beberapa kajian tentang aplikasi turbin angin di daerah urban.
Perbandingan Weld Bead terhadap Contact Tip to Work Distance (CTWD) pada Mesin Welding Tractor GMAW
Full text linkLas GMAW (Gas Metal Arc Welding) merupakan proses penyambungan dua material atau lebih menjadi satu menggunakan arus listrik dengan menggunakan elektroda sebagai bahan tambahan (filler metal). Elektroda tersebut sama dengan bahan dasar logam yang akan disambung. Pengelasan ini juga dilengkapi dengan gas pelindung untuk melindungi hasil pengelasan. Welding tractor adalah alat bantu las yang bertujuan untuk menghasilkan weld bead lebih baik dibandingkan dengan manual welding. Penelitian ini dilakuan dengan membandingkan hasil las (weld bead) dari pengelasan yang jarak contact tipnya berbeda. Hasil las (weld bead) harus sesuai dengan acceptance criteria, dimana weld width maksimal 13 mm dan excess weld maksimal 3 mm. Material yang digunakan adalah plat dengan steel number S550MC. Pengujian dilakuan dengan travel speed sama dan dibantu dengan alat ukur berupa welding guage dan mistar baja untuk mengukur hasil las (weld bead). Penelitian ini dilakukan dengan tiga pengujian contact tip to work distance (CTWD) yang berbeda, yaitu dengan jarak 15 mm, 20 mm, dan 25 mm
A review on the potential of natural and synthetic composites for ballistic resistance
No full textThis review evaluates on the concept and essential of bio composite and the synthetic composite fabric positioned over the years from the previous studies. The sorts and features of matrix and fiber filler reinforcement materials in composites also are discussed. The main findings in this review show that the centre of composite relies on the natural fiber against synthetic and the impact of lamination between them. Therefore, the contemporary hybrid compound for synthetic fiber and bio composite fiber in a composite shape is anticipated performing higher in the issue of mechanical energy in particular within the application of high impact, besides decreased dependency on artificial fiber. The table and figure previous results are comparing the experimental parameters available inside the literature review. This paper goes over the present advancement structure and development procedures included and related works on upgrading low and high impact energy captivation and upgrading the mechanical tenacity for high impact resistance applications.
Uji Performa Mesin Gokart 150 CC Dengan Variasi Beban dan Putaran Mesin
Full text linkAbstractGokart is a four-wheeled simple vehicle, which right now commonly being used as an early stage of racing cause it could train the reflexes of their driver, the decision making and other skills. Gokart usually powered by a two-stroke or four-stroke engine. In gokart racing, other than their driver, engine performance is such a big factor for the race result. The equipment for measure or achieve how much the performance above is called dynamometer, or commonly called “dynotest”. This research is focusing on knowing the engine performance (torque and power) on 150cc petrol-powered two-stroke engine with variation of main jet load of 155, 160 and 165 in 4000 Rpm to 13.000 Rpm. This research is conducted with chassis dynamometer test equipment to get the result of performance data measured by test equipment. From the result of the experiment on lower torque, the power output were so low and could reach maximum followed by engine’s rotation (Rpm), after reaching its peak rpm it will decreasing gradually on higher Rpms. From this research, the best torque is when using a 160 main jet with 16 Nm torque at 10.000 Rpm. Meanwhile, while using a 155 main jet, the torque were decreased by 6,25% and 6,87% while using a 165 main jet. Best power achieved when using a 160 main jet with power of 23,9 HP at 12.000 Rpm. Whereas with a 155 main jet, the power decreased by 4,6% and with a 165 main jet, the power decreased by 1,67%.Keywords: Chassis Dynamometer, Main Jet, Rpm, Torque and PowerAbstrakGokart adalah kendaraan roda empat yang sederhana, gokart biasanya menjadi prasyarat awal untuk kompetisi balap yang lebih besar karena dapat membantu menyiapkan reflek pembalap, mempercepat pengambilan keputusan dan keterampilan. Gokart biasanya digerakkan oleh mesin dua langkah atau empat langkah. Dalam balap gokart, selain pembalap, performa mesin juga sangat menentukan hasil dari balap gokart. Alat yang digunakan untuk mendapatkan atau mengukur besaran performa diatas biasa disebut dynamometer atau lebih dikenal dengan metode dynotest. Penelitian memfokuskan untuk mengetahui performa mesin (torsi dan daya) pada gokart bermesin bensin 2 langkah 150cc dengan variasi beban main jet 155, main jet 160 dan main jet 165 pada putaran mesin 4.000 RPM – 13.000 RPM. Penelitian dilakukan dengan menggunakan alat uji chassis dynamometer untuk mendapatkan data performa yang dapat terukur pada alat uji. Dari hasil eksperimen yang dilakukan pada putaran rendah torsi dan daya yang dihasilkan kecil dan terus akan mencapai maksimum mengikuti kenaikan putaran mesin, setelah mencapai maksimum akan menurun secara perlahan dan terus menurun pada putaran yang lebih tinggi. Hasil penelitian didapatkan torsi terbaik menggunakan main jet 160 dengan nilai torsi 16 Nm pada 10.000 RPM. Sedangkan torsi dengan main jet 155 turun 6,25% dan dengan main jet 165 turun 6,87%. Daya terbaik menggunakan main jet 160 dengan nilai daya 23,9 HP pada 12.000 RPM. Sedangkan dengan main jet 155 turun 4,6% dan dengan main jet 165 turun 1,67%.Kata kunci: Chassis dynamometer, main jet, RPM, torsi dan day
Rancang Bangun Alat Sortasi Gabah Menggunakan Motor Bakar Dengan Kapasitas 5 HP
Full text linkGabah merupakan hasil buah panen dari tanaman padi disawah. Gabah ini diolah untuk menjadi beras yang biasa digunakan untuk makanan pokok kita sehari-hari. Beras ini dimasak untuk dijadikan konsumsi pangan bagi kita. Sebelum beras bisa dikonsumsi, gabah yang merupakan hasil panen harus diolah melalui beberapa tahap. Maka dari itu penulis merancangan alat untuk mempermudah proses penyortiran gabah menjadi beras. Alat yang dibuat mempunyai bentuk minimalis dengan tenaga motor 5 HP dengan bantuan mata pisau roll yang bisa diatur kerenggangan gesekan dengan mata pisau tetap. Proses produksi menghasilkan 54.5 kg beras, rendemen 71.4 % dan efisisensi 41.7 %.Kata kunci : Efisiensi; Gabah; Produksi; Rendeme
The Penetration Depth Of Weld Metal In Underwater Welding With Variations In Water Depth And Water Flow Velocity
Full text linkUnderwater wet welding (UWW) is widely used in the repair of offshore construction and underwater pipelines using the Shielded Metal Arc Welding (SMAW) method. This research was conducted to see the effect of flow (0 m/s, 1 m/s, and 2 m/s) and water depth (2.5 m and 5 m) on the depth weld metal penetration of the SS400 steel underwater welded joints. The control variables used were welding speed of 1.5 mm/s, current of 90 A, electrode E6013 (RB26) with a diameter of 4 mm, type of negative electrode polarity (DC), spraying distance of 10 cm, the direction of spraying in the opposite direction of welding, and fresh water. The results showed that the deeper and fast the flow velocity would decrease the depth of penetration and increases porosity. This is due to the decreased transferability of the molten metal during the welding process
Studi Konsumsi Bahan Bakar Mesin Gokart 150cc dengan Variasi Nilai Oktan Bahan Bakar
Full text linkPetrol fuel is a very inexpendable resource of energy to move or operate a machine to work as it could be. There were so many kinds of fuel such as pertamax, pertamax turbo, and avgas, with each other has a different octane number. Fuel consumption is affected by so many factor, few between them arethe difference between their octane number. The purpose of this study is to found the consumption value of 150cc gokart engine with an octane number variant. This experiment test the specific fuel consumption and air fuel ratio of the engine mentioned above when using different fuel like pertamax, pertamax turbo, and avgas, as all of them tested using dynotest, which connected to computer to track their power value of each fuel used linearly with Rpm increase, idle Rpm, 3000, 5000, 7000 and 9000 Rpm. For specific fuel consumption count based on time needed to emptying each of the fuel tested. From the research, found that specific fuel consumption value was 680 gram/Kwh for pertamax fuel, 357 gram/Kwh for pertamax turbo fuel, and 675 gram/Kwh for avgas. In this research, the factor that affects the specific fuel consumption is the difference between octane number of each fuel type
Analisa Emisi Gas Buang dan Bunyi Mesin Gokart 150 cc dengan Variasi Bahan Bakar dan RPM
Full text linkGokart were so popular on competition scene in Indonesia, using a two-stroke engine with an engine specification being regulated in race regulation. But for now, not only a two-stroke engine, many four-stroke engine gokart race held as it was safer for their driver and environment. It is necessary to do research on emissions and noise emmision so that they can be used as a reference in karting competitions and to maintain the safety of many people involved in the race. Emmision gas test conducted using gas analyzer, while for the noise emmision test using sound level meter. Data taken when the gokart engine in standby, neutral gear. Fuel kinds are the variants of this research, as different fuel means different octane number, such as Pertamax (92), Pertamax Plus (98) and Avgas (102), with data being taken at idle rpm, 3000, 5000, 7000 and 9000 for each different fuel. Data desired were CO, HC, O2, CO2, NOX gas concentration, while for the noise were the decibel value produced by engine. Best result achieved when using Pertamax Plus (98) for emmision gas, which is having emmision gas concentration of CO, HC, O2, CO2, NOX, with a value of 2.25%, 6012.4ppm, 1.98%, 14.33%, and 30.8ppm respectively. Worst result achieved when using Avgas (102), which is having emmision gas concentration of CO, HC, O2, CO2, NOX, with a value of 1.636%, 8849ppm, 0.42%, 17.63%, dan 19ppm respectively. While the noise emmision value based by engine rotation speed, which the speed affects the noise emmision as 1-5 db increasing for each 2000 Rpm increase. While looking for an octane number as a reference, the noise emmision value increase from 1 until 2 for each increase of the fuel octane number.Keywords: Emmision gas, noise emmision, two-stroke engine, gas analyzer, sound level meter