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INDONESIA
Rotasi
Published by Universitas Diponegoro
ISSN : 1411027x     EISSN : 24069620     DOI : -
Core Subject : Engineering,
Mechanical Engineering
Arjuna Subject : -
Articles 676 Documents
 56   57   58   59   60 
Optimization of Machining Parameters and Tool Angle on Surface Quality of Turning Operation Using Taguchi Grey Relational Analysis Nanang Ali Sutisna; Sapto Agus Nowoasto
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.1-7

Abstract

Turning is an operation using a lathe machine and used to remove metal from the outer diameter of a rotating cylindrical workpiece and reduce the workpiece's diameter while it is rotating. In turning operation, there are various parameters available and there have been several studies and researches that examine the way of optimizing turning parameters to achieve preferable performance. Surface roughness quality is one of the most expected performances. This study aims to optimize the tool angle and machining parameters such as depth of cut, feed, and speed on turning operation to achieve the best surface roughness quality. Turning operations are performed based on the orthogonal array for stainless steel. The optimization of parameters and angle tool in this research used Taguchi Grey relational analysis. This method is expected to minimize the surface roughness of the work piece on turning operation. The Taguchi Grey relational analysis method in this research is meant to calculate and analyze the optimal condition for combined parameters and tool angle to get the optimal surface quality. The result shows that the optimum cutting conditions were cutting speed 70 m/min, depth of cut 0.4 mm, the feed rate 0.2 mm/rev, and cutting-tool angle 91º.
Studi Numerik Peningkatan Kinerja pada Turbin Arus Laut Ganda Berputar Searah Sony Junianto; Mukhtasor Mukhtasor; Rudi Walujo Prastianto
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.1-7

Abstract

Indonesia saat ini terus berupaya mewujudkan program transisi energi bersih. Salah satu programnya adalah peningkatan kapasita energi baru dan terbarukan. Berdasarkan kondisi geografis Indonesia, sumber energi terbarukan yang tersedia relatif besar adalah energi laut, terutama energi arus laut yang perkembangan teknologinya relatif pesat. Teknologi ini menggunakan turbin arus laut untuk mengubah kecepatan arus laut menjadi listrik. Hingga saat ini, penelitian turbin arus laut tunggal terus dikembangkan. Di lain sisi, peningkatan kapasitasnya juga terus dikembangkan dengan menggunakan turbin jamak. Langkah awal dalam meneliti turbin arus laut jamak adalah dengan menganalisis kinerja dari turbin ganda. Oleh karenanya, laporan ilmiah ini menjelaskan kinerja turbin ganda yang dilakukan secara metode numerik. Analisis yang dilakukan berdasarkan teori pada Computational Fluid Dynamics (CFD). Obyek penelitiannya adalah turbin ganda yang berputar searah yang artinya putaran kedua turbin pada arah yang sama. Turbin-turbin tersebut disusun dengan menggunakan NACA 63(4)-021. Hasil penelitian ini adalah kinerja turbin kedua meningkat sekitar 42,86-71,43% dari turbin pertama dimana kinerja keduanya secara bersama-sama menjadi 1,21 kali dari kinerja turbin tunggal.
Modeling and Static Analysis of Pressure Vessel in Full Welded Connections Lydia Anggraini
ROTASI Vol 25, No 1 (2023): VOLUME 25, NOMOR 1, JANUARI 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.1.1-7

Abstract

The pressure analysis on the cylindrical pressure vessel is simulated computationally with the finite element method and evaluated from some point of view performance parameters. In this study, the stress elastic analysis method is used with basic calculations to determine the design thickness of the shell, head, nozzle, and material specifications used for pressure vessel analysis. For contraction design by using Autodesk Inventor software for 3D models. This analysis used the finite element method with ANSYS Workbench software, including thermal transient analysis of welded joints then connected with structural analysis of analysts for construction design. It includes material properties and weld joint design on each part of the overall pressure vessel. This result can be used to more rapidly identify critical design variables to optimize the design and find out the maximum deformation occurring in each part of the pressure vessel. The resulting analysis leads to the selection of appropriate measurements for structural use and thermal transient heat transfer analysis on the weld joints on the adjacent welding Nozzle. Interconnect and overlap welded joints with manhole pad welding and identification of the most critical deformation measurements based on parameters.
Angles of Tilted and Length of Resonator Effect on The Efficiency of A Close-Open-Type Thermoacoustic Rinasa Agistya Anugrah; Fajar Anggara
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.1-8

Abstract

In determining the optimal design of the thermoacoustic engine, parameters were studied: tilt angle and resonator length. The purpose of this study is to find the highest efficiency in tilt angle and resonator length for a standing wave thermoacoustic engine (SWTE). The heat transfer properties therein were detected at three tilt angles of -90°, 0° and 90°, resulting in three resonator lengths variations such as 390, 780 and 1170 mm. This study was conducted to determine the magnitude of pressure amplitude using a two-pressure transducer method of recording by data acquisition and counting with Matlab software. The results of this study show that a tilt angle of 90° has the highest efficiency and a tilt angle of 0° has the lowest efficiency. A cavity length of 390mm yielded the highest SWTE efficiency, with an efficiency of 5.5%.
Pengaruh Variasi Kecepatan Pemakanan (Feed Rate) terhadap Gaya Potong Proses Gurdi dengan Material Aluminium Fitria Nofita Sari
ROTASI Vol 25, No 1 (2023): VOLUME 25, NOMOR 1, JANUARI 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.1.1-7

Abstract

Proses gurdi merupakan salah satu proses pemesinan yang penting untuk membuat lubang pada benda kerja dengan menggunakan mata bor. Selama proses gurdi, benda kerja menghasilkan gaya potong. Gaya potong dipengaruhi oleh beberapa parameter antara lain jenis material, kecepatan potong, geometri pahat, kecepatan pemakanan, dan metode pendinginan. Gaya potong merupakan salah satu parameter yang dapat digunakan untuk memantau kondisi dari proses gurdi, menghindari kerusakan pahat, dan meningkatkan kualitas lubang hasil penggurdian. Artikel ini membahas pengaruh variasi kecepatan pemakanan (feed rate) terhadap gaya potong. Finite Element Method (FEM) digunakan untuk menganalisis gaya potong pada penggurdian Aluminium menggunakan pahat karbida. Hasil penelitian menunjukkan bahwa semakin besar nilai feed rate maka semakin besar pula nilai gaya potong. Jadi dapat disimpulkan bahwa feed rate mempengaruhi gaya potong.
Performance Analysis of Working Fluids on Organic Ranking Cycle Using Waste Heat from Flue Gas Wahyu Nur Fadilah; Kartika Meylia Putri; Joke Pratilastiarso
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.1-7

Abstract

The increasing in electricity demand was inversely proportional to the supply of fossil fuels. It required various parties to find innovations to produce more electrical energy without increasing the use of fossil fuels. Organic Rankine Cycle (ORC) was one of the ways to generate electricity with a low heat source and it was affected by the type of refrigerant used as a working fluid. Therefore, this research was conducted to find a working fluid that produced good thermal efficiency and power for the ORC system by utilizing the flue gas from the steam power plant. Simulations were carried out using CoolProp software to determine the properties of the working fluid to be used and Cycle Tempo software to simulate the ORC system. This study used variations of working fluid R134a, R404A, R407C, R410A, and R507. In addition, flowrate variations of 100 kg/s, 150 kg/s, 200 kg/s, 250 kg/s, and 300 kg/s were also used. From this research, the highest thermal efficiency occurred at a flowrate of 300 kg/s using a working fluid R407C, it was 36.19%. The largest net power was also obtained at a flow rate of 300 kg/s using the working fluid R407C, it was 26980.9 kW.
Numerical Study of Flat-top Piston Head Structure Under Different Materials Hendry Sakke Tira; Muhammad Ponco Zulfikar; I Made Adi Sayoga
ROTASI Vol 25, No 1 (2023): VOLUME 25, NOMOR 1, JANUARI 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.1.1-6

Abstract

Piston is an important component of two-wheeler since it is able to generate high pressure and convey combustion energy into crank rotation. Piston is typically made of aluminium alloy and other materials that can endure extremely high pressure and heat on the surface during combustion. Aluminium alloy and magnesium alloy are two distinctive materials that are frequently used in piston head. The objective of this study is to use numerical analysis to investigate and analyse a flat-top piston head made of two different materials. The design process allows usage Solidworks software, and the analysis process makes use of Ansys software. The Ansys simulation is intended for evaluating the maximum stress, total deformation variability, and safety factor for each material analysed. The findings from the analysis indicate that the deformation of the piston head made of aluminium alloy is smaller than that of magnesium. Whereas the aluminium alloy has a lower safety factor than magnesium. The von Mises stresses for the two materials, however, are essentially equal.
Analisis Fisika dan Kimia Material Polimer Ramah Lingkungan Edible film Berbahan Rumput Laut E-Cottonii Sebagai Pengganti Kemasan Plastik Agus Dwi Putra; Yayi Febdia Pradani; Bella Cornelia Tjiptady
ROTASI Vol 24, No 3 (2022): VOLUME 24, NOMOR 3, JULI 2022
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.24.3.22-28

Abstract

Penelitian ini bertujuan untuk menanggulangi masalah sampah plastik terutama di indonesia. Adapun target dalam penelitian ini yaitu untuk menguji material polimer ramah lingkungan pengganti kemasan plastik yakni edible film. Pengujian pada penelitian ini dibagi menjadi dua jenis yaitu pengujian secara fisika dan secara kimia. Pengujian fisika dimaksudkan untuk menguji tingkat ketebalan edible film, kuat Tarik, elongasi, dan titik leleh. Kemudian pengujian kimia ditujukan untuk menguji kadar air dan kadar karbohidrat edible film. Edible film yang diujikan meliputi tiga jenis variasi dengan masing-masing variasi memiliki campuran tepung jagung dan gliserol dengann konsentrasi takaran yang berbeda. Hasil menunjukkan bahwa ketebalan maksimum edible film mencapai 0,17 mm sedangkan ketebalan minimum sebesar 0,062 mm. Berikutnya hasil pengujian kuat Tarik didapatkan bahwa kuat Tarik maksimum mencapai 82 N/cm2 sedangkan kuat Tarik minimum sebasar 18 N/cm2. Pada pengujian tingkat elongasi didapatkan hasil bahwa elongasi maksimum sebesar 33% dan elongasi minimum sebesar 20,5%. Selanjutnya pada pengajuan titik leleh edible film didapatkan hasil titik leleh maksimum sebesar 75,8oC sedangkan titik leleh minimum sebesar 65,9oC. Pada pengujian kadar air dan kadar karbohidrat didapatkan kadar air dan karbohidrat maksimum adalah 13,67% dan 71,68%. Sedangkan kadar ari dan kadar karbihidrat minimum sebesar 12,9% dan 60,8%.
Flutter Analysis on the Wing of Typical 4.5th Generation Fighter Aircraft Ahmad Hasan Fauzi
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.37-43

Abstract

Flutter is a phenomenon of dynamic instability caused by aerodynamic force, inertial force, and structural elasticity. It is recognized by catastrophic oscillation of the structure at a certain flow speed. In aircraft design, flutter analysis must be conducted to ensure that the aircraft does not undergo flutter in its operational region. This work focuses on flutter analysis of the wing of a 4.5th generation fighter aircraft, using the MSC.FLDS/PATRAN/NASTRAN software. The process involves several procedures, including structure modeling, structural dynamics analysis, aerodynamic load modeling, and flutter analysis. The structure is modeled using the finite element method, while the doublet lattice method is used for aerodynamic load modeling in the subsonic regime and ZONE 51 in the supersonic regime. The p-k method is used to solve the flutter analysis. After conducting flutter analysis in the basic configuration and condition, a parametric study is performed to understand how some parameters affect the change in flutter characteristics. The results of the parametric study show that the speed and characteristics of flutter change with changes in flight conditions (altitude and Mach number) and mass configuration (position of the missile in the spanwise direction). Flight conditions change the aerodynamic load in the system, while missile position and structure thickness change the inertia and stiffness of the system. Changes in these parameters - aerodynamic, inertia, and stiffness - affect the flutter speed and characteristics.
Analysis of High-Speed Train Braking Systems: Components, Braking Force, and Air Consumption P Paryanto; Joga D Setiawan; Abduh B Adriathmaa; Akhmat Busori; Mulyadi s Harjono; Nur Cahyo
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.%p

Abstract

Ensuring the accuracy of parameters involved in high-speed train braking is essential for passenger safety and efficient operation. To achieve this, it is crucial to verify the force values, input and output specifications of braking system devices, and ensure they align with the desired values. This can be accomplished through quantitative research, which involves collecting braking system data from the train manufacturing company and consulting the technical book provided by the braking system manufacturer. In this particular research, the braking system of the high-speed train under investigation is designed as a combination of regenerative and electro-pneumatic braking. The regenerative braking force, determined by the DC motor and control, amounts to 95.46 kN, enabling train to decelerate from 220 km/h to 90 km/h. Subsequently, the electro-pneumatic braking continues the regenerative braking, with a force value resulting from the calculation of the output value on devices of 296.4 kN, bringing train to a complete stop. The air demand required to supply the pneumatic components of braking devices as well as the air demand of other devices in train is 121.35 liters/min. This figure accounts for the pneumatic supply needed for braking system's proper functioning, along with other pneumatic-dependent devices present on train. To validate the proposed design, a simulation of train braking operations was conducted using the data obtained from the research. This simulation aims to evaluate the effectiveness and efficiency of high-speed train braking system design, providing valuable insights for further improvements and optimizations.

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