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Ditemukan: 22 dokumenPENGEMBANGAN PENGUKURAN KETELITIAN GEOMETRIK MESIN CNC MILLING VERTIKAL TIGA SUMBU DENGAN MODEL MULTI CENTER DOUBLE BALLBAR MEASUREMENT
Penggunaan mesin perkakas mempunyai dampak yang signifikan terhadap produktivitas dalam industri manufaktur sejak revolusi industri. Manajemen peralatan mesin adalah kunci dalam mengurangi waktu henti mesin dan biaya pemeliharaan, sehingga dapat menghasilkan mutu dan kualitas produk akhir yang baik secara terus-menerus. Dalam konteks ini, pengembangan metode pengukuran kesalahan geometrik pada mesin CNC menjadi poin penting untuk menjaga keakuratan dan presisi produksi. Tugas akhir ini bertujuan untuk mengidentifikasi dan menganalisis kesalahan geometrik pada sumbu X dan Y di seluruh bidang kerja mesin CNC milling menggunakan alat ukur double ballbar (DBB). Pengukuran dilakukan pada 18 titik koordinat pada bidang XY mesin CNC, dengan mempertimbangkan variasi kecepatan makan pada satu tingkat kecepatan optimal untuk pengukuran kesalahan geometrik, yaitu 3.000 mm/min. Hasil pengukuran menunjukkan adanya variasi nilai deviasi pada beberapa titik, yang kemudian divalidasi dengan hasil pengukuran kelurusan rekan dengan menggunakan laser interferometer. Hasil penelitian menunjukkan adanya perbedaan nilai deviasi yang cukup signifikan pada beberapa titik, dengan nilai error maksimum sebesar 4.545 ?m pada titik yang ditandai dengan notasi X4,Y2. Metode multi center DBB mampu memberikan gambaran yang detail terhadap distribusi deviasi yang terjadi pada mesin CNC, meskipun masih terdapat beberapa keterbatasan terkait dengan akurasi hasil pengukuran. Validasi lebih dari 1 data pengukuran kelurusan laser interferometer, serta pengujian dengan mempertimbangkan nilai pada sumbu Z yang lain diperlukan untuk mendapatkan hasil yang lebih menyeluruh dan komprehensif.
OPTIMIZED HIGH-PRESSURE HYDROGEN TANK DESIGN FOR AUTOMOTIVE APPLICATIONS
With concerns over rising global greenhouse gas emissions, the automotive industry in particular has been seeking more environmentally friendly technology. Hydrogen Vehicles (HV) such as Fuel Cell Electric Vehicles (FCEVs) and Hydrogen Internal Combustion Engine Vehicles (HICEVs), have shown high potential with advantages including zero tailpipe emissions, competitive performance to existing options, and quick refueling times. However issues stemming from hydrogen tank designs significantly increase the cost of HVs, and hamper its efficiency, so much so that the adoption of HVs has been held back in recent years. To resolve these issues, this thesis proposes an alternative design for a high-pressure gaseous hydrogen tank, where the interior is partitioned into smaller compartments. The scope of this thesis is selecting/determening the optimal partition material and geometry, hence establishing a preliminary foundation for further development in alternative hydrogen tank designs.
PERANCANGAN TURBIN AIR JENIS CROSSFLOW DENGAN HEAD 25 METER DAN DEBIT 300 LITER/DETIK
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STUDI NUMERIKAL PENGARUH KESALAHAN GEOMETRI PADA SPESIMEN HAT-SHAPED UNTUK PENGUJIAN SPLIT HOPKINSON SHEAR BAR
High-strain rate design requirements for a product require the consideration of materials' properties under said loading condition. Therefore, reliable material testing under a high-strain rate is needed. The Split-Hopkinson Pressure Bar (SHPB) is a common apparatus for dynamic stress-strain response under high-strain rates. It can be modified for shear stress, becoming a Split- Hopkinson Shear Bar (SHSB) using a hat-shaped specimen as the test object. The manufacturing of a hat-shaped specimen requires minimal tolerance, considering specimen geometry errors might alter the test results. However, less tolerance also means more difficult production and higher costs. This research aims to study the effect of geometric error of hat-shaped specimen for the SHSB by using finite element analysis. This research involves literature study, data gathering, 3D modelling of split-Hopkinson pressure bars and specimens, numerical simulation using Abaqus CAE, analysis of results, and conclusion generation for improved high-shear strain rate testing, with recommendations for better testing. Three types of geometric error are studied. The geometric errors studied are axis perpendicularity, surface parallelism, and surface flatness. This research concludes a geometric tolerance recommendation for axis perpendicularity of 0.260 mm, surface parallelism of 0.087 mm, and surface flatness of 0.130 mm based on the characteristic curve error limit.
PENYUSUNAN METODE UJI UNJUK KERJA MINYAK LUMAS TRANSMISI OTOMATIS
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PENGEMBANGAN SISTEM MODULAR ELEKTRONIK ALAT UKUR LEBAR JALUR REL KERETA API
Proposal ini berisi rencana pengembangan alat untuk mengukur ketidakteraturan jalur kereta yang dapat mengakibatkan perjalanan kereta api terganggu. Pertama dibahas jenis - jenis ketidakteraturan jalan dan dampak yang diakibatkan. Selanjutnya dibahas metodologi pengukuran ketidakteraturan jalur dan sensorsensor yang digunakan untuk mengukur ketidakteraturan jalur terebut. Dari berbagai jenis ketidakteraturan, dipilih ketidak teraturan lebar jalur sebagai parameter yang akan diukur oleh alat yang akan dikembangkan. Alat ini dirancang untuk dapat dioperasikan baik secara manual atau diintegrasikan dengan lori. Dalam tahap proposal ini, telah dilakukan rancangan awal alat uji lebar rel dan pemilihan sensor yang sesuai. Sensor telah diuji secara statik dan dinamik dan hasilhasil menunjukkan kinerja sensor telah sesuai dengan spesifikasi teknisnya. Kegiatan pengembangan akan dilanjutkan dengan pembuatan alat, uji fungsional dan validasi di laboratorium dan di lapangan. Hasil-hasil yang diperoleh akan digunakan untuk menyempurnakan alat yang dibuat. Pengembangan alat ini diharapkan akan dapat mendukung pengembangan perkeretaapian di Indonesia.
FLOW SIMULATION OF THE ROCKET NOZZLE
<p align="justify">Since its first use, rockets have been continuously employed by people of many cultures, especially in current times with both use for civilian and military purposes. However, as it is a sensitive topic due to its extensive use as missile, publicly available research data on the matter is severely limited. As such, as a higher learning institution, ITB ought to start its independent research on the matter. The most common system in use is solid-propellant rocket motor, due to its relatively simple design and inexpensive. This system employs a combustion reaction of the solid propellant to produce hot gas, which will be ejected as a high-velocity flow, producing thrust. Observation of this working principle, while also identifying crucial properties such as chamber pressure and temperature, mass flowrate, and thrust is beneficial for gaining insight into the matter The research will be conducted solely by numerical means, as it is the most appropriate method to conduct the simulation. Two initial simulations were done to validate the general simulation. The first main simulation was aimed at producing a transient process of a solid rocket motor. A second main simulation, a steady-state type, was done to produce known phenomena called overexpansion and underexpansion flow, as a means of validation and gaining additional insight. The result for the first simulation consisted of primary properties and performance parameters. The value of properties at steady state from simulation will then be compared with the value from theory, with error respectively which yields less than 10% for most properties. The second simulation conducted produced the desirable phenomena, observed using its Mach number contour, and properties of Mach number, pressure, and temperature along the centerline.<p align="justify">