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Contact Name
Dharu
Contact Email
dharufs@staff.uns.ac.id
Phone
+6281217717892
Journal Mail Official
mesin@ft.uns.ac.id
Editorial Address
Jl. Ir. Sutami no 36 A, Building I, Faculty of Engineering, Universitas Sebelas Maret, Surakarta
Location
Kota surakarta,
Jawa tengah
INDONESIA
Mekanika: Majalah Ilmiah Mekanika
ISSN : 14127962     EISSN : 25793144     DOI : https://doi.org/10.20961/mekanika
Core Subject :
"Mekanika: Majalah Ilmiah Mekanika" is an open-access journal published by Mechanical Engineering Study Program, Faculty of Engineering, Universitas Sebelas Maret. Mekanika invites scholars, researchers and practioners who have interest in mechanical engineering to publish their articles and also provides forums for them to share their works and knowledge. Mekanika focuses on the area of materials engineering and science, design, energy, manufacturing and construction but is not limited to. Both English and Bahasa are accepted in this journal. Mekanika has two issues every year (March and September) and aims to publish more frequently in the future.
Articles 91 Documents
Pengaruh beban kompaksi dan suhu sintering terhadap densitas dan sifat mekanik aluminium water atomized Heru Sukanto
Mekanika: Majalah Ilmiah Mekanika Vol 17, No 2 (2018): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v17i2.35126

Abstract

The powder size used in the research were maximum of 297mm and maximum of 105m resulted by water atomization. Both powder sizes were dry mixed by ratio of 65:35 %wt and was added by 1,25% wt of wax. Mixing was taking a place in steel cylinder with diameter of 2” roteted at 140 rpm for 2 hr. Green body was formed by pressing pressure of 280, 340, 400 and 435 Mpa. Sintering was conducted in argon and temperatures variation of 500, 550, 600 and 650oC for 2 hr.The results show thet sintering temperature change have no significant effects on density and mechanical properties while presing pressure have dominantly effects. Traverse rupture strength, density and hardness growth with  increasing pressing pressure but they will decrease with increasing sintering temperature. The best increasing of mechanical properties was occurred at temperature sintering of 500oC and compaction pressure of 400 Mpa.
STUDI EKSPERIMENTAL PERPINDAHAN KALOR KONVEKSI, PENURUNAN TEKANAN DAN FAKTOR GESEKAN PADA ALAT PENUKAR KALOR MENGGUNAKAN MICRO-FIN TUBE Ahmad Imam Rifa’i; Budi Kristiawan; Agung Tri Wijayanta
Mekanika: Majalah Ilmiah Mekanika Vol 18, No 1 (2019): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v18i1.35040

Abstract

Micro-fin is the popular technique for increasing heat transfer performance of the heat exchangers. In this research, the heat transfer coefficient of water inside counter-flow heat exchangers with micro-fin was investigated by experiment at the Reynolds number (Re) was varied from 4000-10,000. The results show that the heat transfer coefficient increase with increasing Reynolds number. Furthermore, effect helical micro-fin increasing pressure drop and friction factor at turbulent flow region.
Two-Phase Flow Characteristics on The Extensive Expansion Channel Latif Ngudi Wibawanto; Budi Santoso; Wibawa Endra Juwana
Mekanika: Majalah Ilmiah Mekanika Vol 16, No 2 (2017): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v16i2.35056

Abstract

This research was conducted to find out the flow characteristic of two phases through channel with sudden expansion in the form of change of flow pattern and pressure recovery. The test was conducted with variation of superficial velocity of water 0.2-1.3 m / s and superficial air velocity of 0.2-1.9 m / s resulting in pattern of three flow patterns ie bubble, plug, and slug. The expansion channel resulted in some changes to the flow pattern that originally plugs in the upstream channel into bubble in the downstream channel and the slug becomes plug. Pressure recovery experimental results were compared with the homogeneous model flow equation and Wadle correlation, the two correlations had predictions with standard deviation values of 0.32 and 0.43.
Cu Addition Effect Analysis on Matrix Of Remelting Piston Aluminium Composite with Silica Sand Reinsforcement to The Impact Strength and Micro Structure on Aluminuim Matrix Composite Using Stir-Casting Method Fajar Paundra; Teguh Triyono; Wahyu Purwo Raharjo
Mekanika: Majalah Ilmiah Mekanika Vol 16, No 1 (2017): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v16i1.35051

Abstract

AMC (Aluminium Matrix Composite) is material which has a great potential for being developed. This research was done to find effect added of Cu variation for impact strength and microstructure on Al-Si composite. Mass fractions of sand silika is 3% and Cu variation adding is 0, 1, 2, 3 & 4%. Composite manufacture is using stir casting method with stirring 600 rpm during of 5 minutes on semi solid temperature. Speciments were tested using optical microscope and impact charpy testing machine. The value impact of composite without adding Cu is 0,333 J/mm2 after added Cu value down. Until adding Cu 4% the value impact is 0,104 J/mm2. Micro photograph showed the result of porosity and SiO2 unform distribution with the adding of Cu to the composite. From the test results it is known that the strength of the impact decreases with mass fraction addition Cu. This is because the addition of Cu can increase the porosity and formed CuAl2 phase which are brittle.
EXPERIMENTAL STUDY THE EFFECT ANGLE OF BLADE ON THE ELECTRICAL POWER OUTPUT OF PROPELLER PICOHYDRO TURBINE Abdullah Shalih; Purwadi Joko Widodo; Dwi Aries Himawanto
Mekanika: Majalah Ilmiah Mekanika Vol 18, No 2 (2019): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v18i2.35405

Abstract

This study aimed to analyze the effect of angle of blade on the horizontal flow to the performance of the propeller water turbine. The experiments were performed using several test parameters including the angle of blade on the variation mass flow rate of water. With potential head 2 meters and variated turbine blade angle to achieved optimal power generated.  The result showed that the variation of angle of blade with 300 angles and 11.6 l/s mass flow rate of water was the best variation to improve the performance of the propeller water turbine. The best variation can generated 32 Watt of electric power.
Pengaruh variasi kecepatan putar dan diameter tool terhadap sifat mekanik sambungan fssw aluminium alloy 5052 dan baja ss400 Wahid Ramadhan; Nurul Muhayat; T Triyono
Mekanika: Majalah Ilmiah Mekanika Vol 17, No 1 (2018): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v17i1.35046

Abstract

Friction stir spot welding (FSSW) is a development from solid state welding to jointa different materials (dissimilar). Dissimilar FSSW is widely used in the automotive industry due to the advantages of joining these two materials with weight savings while exploiting the best strength. This research aims to know the effect of welding parameters of rotation speed and tool diameter on mechanical properties on dissimilar FSSW aluminum alloy 5052 and SS400 steel. Variations in rotational speed used is 800, 1250, 1600, 2000 rpm and tool diameter 10, 12, 14 mm. Plunge depth and dwell time in this research were made uniform. This research used a lap joint configuration with aluminum plate placed on the top and steel plate placed on the bottom. Physical characteristics were analyzed through observation of macro and microstructures, while mechanical characteristics through vickers hardness testing and shear tensile testing. The results indicate that the diameter of 10 mm tool and 1600 rpm rotation speed produce the highest tensile shear load value of 2.4 kN with interface fracture.
Pengaruh kecepatan gerak torch pemanas pada proses automatic flame hardening terhadap nilai kekerasan dan kekuatan tarik baja karbon medium Andi Purwanto; Teguh Triyono; Sukmaji Indro Cahyono
Mekanika: Majalah Ilmiah Mekanika Vol 17, No 2 (2018): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v17i2.35127

Abstract

Steel material was widely used and obtained in the industry and automotive application. The hardness of the surface area and the ductile of the core were produced by using heat treatment, in this case, automatic flame hardening method was used. The heat treatment process was done in order to increase the surface temperature by using a carburizing flame and then the cooling process by using water cooling medium continously followed. The aim of this research was to identify the effect the heating torch velocity on the surface hardness and the tensile strength of the medium carbon steel using the automatic flame hardening process. Some variations were used in this research were heating torch velocities at 10 mm/min, 20 mm/min, 30 mm/min, and 40 mm/min. The results shows that the heating torch velocity at speed 10 mm/min was the most optimal parameter. The maximum hardness of the surface area is reached 398.9 VHN, while the highest tensile strength was 647.3 MPa and the perlit-ferrit phase was also formed. By these results, the hard properties on the surface area and the ductile properties in the middle area of the specimen could be obtained.
DIAGNOSA KERUSAKAN BANTALAN BOLA MENGGUNAKAN METODE SUPPORT VECTOR MACHINE Muhammad Fathurrohman; R. Lulus Lambang G. H; Didik Djoko Susilo
Mekanika: Majalah Ilmiah Mekanika Vol 18, No 1 (2019): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v18i1.35041

Abstract

Bearings are the critical part of any rotating machine. The catastrophic failure of the bearing can lead to fatal and harmful to the operation of the machine. Therefore, predictive maintenance based on condition monitoring of bearing is very important. The objective of this research is to apply Support Vector Machine (SVM) method for fault diagnosis of the ball bearing. The research was carried out at the bearing test rig. Four types of ball bearing condition, such as normal, inner race defect, ball defect, and outer race defect were measured of the vibration signals using data acquisition with a sampling frequency of 20 kHz at the constant speed of 1400 RPM. Various features were extracted from vibration signals in time domain, such as RMS, variance, standard deviation, crest factor, shape factor, skewness, kurtosis, log energy entropy and sure entropy. PCA transformation was employed to reduce the dimension of feature extracted data. SVM classification problems were solved using MATLAB 2016a. The results showed that the application of RBF kernel function with the C parameter =1 was the best configuration. The training model accuracy was 98.93% and the testing accuracy of SVM was 97.5%. Finally, the research results show that the SVM classification method can be used to diagnose the fault condition of the ball bearing..
Natural Convection Numeric Simulation on Metal Freezing Using Differential Method Heri Suprianto; Eko Prasetyo Budiana; Purwadi Joko Widodo
Mekanika: Majalah Ilmiah Mekanika Vol 16, No 2 (2017): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v16i2.35057

Abstract

The research of modeling of natural convection in metal solidification process with finite different method was conducted to determine temperature distribution and fluid flow profil with variations value Rayleigh number. The research conducted by solving governing equation of natural convection with finite difference approximation. Governing equation of natural convection consist of continuity equation, momentum equations, and energy equation. The ADI (Alternating Directional Implicit) method was used to discriteze for governing equation of natural convection. Finite difference method was written in Fortran language whereas the temperature distribution and fluid flow profile were visualized with Matlab software. The results of this research was validated by comparing the results obtained with Rajiv Sampath research. Comparison of the results of research showed good agreement. The result showed that solidification process occurs faster at Ra 10^4 compared with 10^5 and 10^6
Welding Current and Shielding Gas Flow Rate Effect to The Intermetalic Layer Formation of Tungsten Inert Gas (Tig) on Dissimilar Metals Weld Joints Between Galvanized Steel and Aluminium Aa 5052 By Using Al-Si 4043 Filler Gilang Sigit Saputro; Triyono .; Nurul Muhayat
Mekanika: Majalah Ilmiah Mekanika Vol 16, No 1 (2017): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v16i1.35052

Abstract

Tungsten Inert Gas welding of galvanized steel-aluminium useful for weight reduction, improve perform and reduce cost production. The effect of welding parameters, welding current and shielding gas flow rate on the intermetallic formation and hardness of dissimilar metals weld joint between galvanized steel and aluminium by using AA 5052 filler was determined. In this research, welding speed was consistent kept. The welding parameters were obtained by using welding currents of 70, 80 and 90 A, shielding gas flow rate of 10, 12 and 14 litre/min. The intermetallic layer thickness increased by welding currents of 70 A to 80 A, but then it dropped on 90 A. The higher of a shielding gas flow rate, the lower the thickness of the intermetallic layer. The higher of a welding current, the lower the hardness of weld. The higher of a shielding gas flow rate, the greater the hardness of weld. As a result,the maximum hardness by current variation of 70 A and a shielding gas flow rate of 14 Litre/min was 100.9 HVN.

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