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All Journal Rekayasa Mesin International Journal of Mechanical Engineering Technologies and Applications (MECHTA) GMPI Conference Series
Djarot B. Darmadi, Djarot B.
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Humanities Automotive Engineering Computer Science & IT Decision Sciences, Operations Research & Management Energy Engineering Industrial & Manufacturing Engineering Mechanical Engineering Physics Social Sciences

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Analisis Penyerapan Energi Dan Pola Deformasi Crash Box Dengan Variasi Sudut Tirus Dinding Crash Box Pada Uji Simulasi Tabrakan Arah Frontal Choiron, Moch. Agus; Darmadi, Djarot B.; Anwari, Bintang Rahmaddian
Jurnal Rekayasa Mesin Vol 6, No 1 (2015)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1518.226 KB) | DOI: 10.21776/ub.jrm.2015.006.01.11

Abstract

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.
Pengaruh Variasi Sambungan pada Crash Box Multi Segmen terhadap Kemampuan Penyerapan Energi dengan Uji Quasi Static Halman, Halman; Choiron, Moch. Agus; Darmadi, Djarot B.
Jurnal Rekayasa Mesin Vol 9, No 1 (2018)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (411.487 KB) | DOI: 10.21776/ub.jrm.2018.009.01.7

Abstract

Along with the elevating number of cars, accidents due to car crashes are increasing. Therefore, technology is needed to reduce the occurrence of the drivers’ injuries. Crash box is one of the potential passive safety technology which is widely observed today. Crash box is installed between bumper and chassis, aims to reduce the cassualties when the car crashes. In this article, crash box research was conducted by real experimental method through quasi-static test to evaluate the energy absorption capability of circular-shaped multi-segment crash box. Crash box material was made from aluminum A6063. The connection on each segment is a chamfer with 45o angle. The connections between segments 1 and 2 were varied with 3 connection models, those are 1/4, 1/3 and 1/2 of the total length, i.e.120 mm. The results of the study showed that, the highest energy absorption obtained from the crash box with connection of 1/2 and the energy absorption is 5249.726 J. Crash box type of 1/4 and 1/3 exhibit energy absorption of 3886.238 J and 3106.027 J respectively. Generally, the deformation pattern on the crash box is mixed-mode (axisymmetric-diamond). 
Model Termal Proses Pengelasan Keliling Multipass Pada Sambungan Pipa API-X70 Darmadi, Djarot B.
Jurnal Rekayasa Mesin Vol 5, No 3 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Thermal model is the first step in a welding model which may be coupled with mechanical and/or metallurgical model andmistakes in thermal model mislead the next steps. This paper discusses validated thermal model using transformed volumetric Goldak’s heat source model. Birth and death technique was used to represents growing weld bead. Well matched temperature histories of the model and measurements confirmed the correctness of the proposed thermal model.Keywords : Thermal model, Transformed heat source, Birth and death technique
Hardening Baja AISI 1045 Menggunakan Gel Aloe Vera Sebagai Media Pendingin Budiyanto, Eko; Choiron, Moch. Agus; Darmadi, Djarot B.
Jurnal Rekayasa Mesin Vol. 7 No. 2 (2016)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (979.156 KB) | DOI: 10.21776/ub.jrm.2016.007.02.3

Abstract

Quenching is a cooling method of heat treatment for metal hardening. Quenching refers to the process of rapidly cooling metal parts from the austenitizing or solution treating temperature, typically from within the range of 815 to 970 °C for steel. The selection of a quenchant medium depends on the hardenability of the particular alloy, the section thickness and shape involved, and the cooling rates to achieve the desired microstructure. The liquid quenchants of oil is commonly used in industrial manufacture. But, oil is not environmental. The aim of this research research is to find new quenchant for change oil as quenchant to more environmental. Gel aloe vera is purposed for it. The material used in this study is AISI 1045 steel. Cooling curve and cooling rate is measured by finite element model, ANSYS APDL 14.5. True experimental is done to view microstructure and measure hardness of steel. Simulation result shown that gel aloe vera has almost similar cooling curve and cooling rate with oil. Microstructure result of steel for gel aloe vera as quenchant is martensite in surface, bainite in center, and pearlite in between surface and center. Hardness number of steel for gel aloe vera as quenchant is 189.63 HVN in surface, 182.566 HVN in center, and 162.866 HVN in between surface and center. By simulation and true experimental analisys concluded that gel aloe vera has opportunities to change oil as quenchant for hardening process.
Perilaku Tarik Komposit Laminat Serat Kulit Waru-Aluminium Suteja, Suteja; Purnowidodo, Anindito; Darmadi, Djarot B.; Sari, Nasmi Herlina
Jurnal Rekayasa Mesin Vol 10, No 1 (2019)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2019.010.01.3

Abstract

Waru fiber-aluminium laminate composite is engineering materials which have high stiffness, strength properties and weight to strength ratio. The aim of this study is to find out the effect of the number of waru fiber to tensile strength on laminate composite waru fiber-Aluminium. The process of laminating composite waru fiber-aluminium is done by vacuum infusion resin method with layers variation 1, 2, 3, 4  and fiber direction 45/45 angle woven basket. The result shows that the tensile strength of the waru-Al fiber composite decreases and the elongation value of the composite increases due to the addition of layers of fiber waru lower bond strength on adhesive-aluminum and adhesive-waru. The lowest tensile strength of 153,642 MPa has occurred in composite with 4 layers of waru fibre.
Perubahan Sifat Mekanik Hasil Pengelasan Gesek Aluminium 6061 Akibat Perubahan Temperatur Lingkungan Kido, Muhammad Ikram; Sugiarto, Sugiarto; Darmadi, Djarot B.
Jurnal Rekayasa Mesin Vol 12, No 1 (2021)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2021.012.01.11

Abstract

Friction welding is a welding technique that utilizes heat due to surface friction between a rotating and pressing workpiece. This study aims to analyze the effect of environmental temperature variations on the mechanical properties of Al 6061 alloys, friction welding specimens with variations in room temperature (27ºC), 50 ºC, 75 ºC, 100 ºC, 125 ºC, and 150 ºC. Welding is carried out using a lathe with a rotation speed of 1600 rpm, a workpiece diameter of 15 mm, a champer angle of 15º, a friction force of 65 bar for 6 seconds, and a final compressive force of 325 bar for 60 seconds. Changes in mechanical properties in terms of tensile strength and hardness. The results showed that the higher working environment temperature produced greater tensile strength than Al 6061 friction weld joints. From macro-micro observations, it was found that specimens with large tensile strength (specimens welded at 100 ºC, 125 ºC, and 150 ºC) had a large area (Zpl) and finer granules when compared to specimens with small tensile strength (specimens welded at room temperature (27 ºC), 50 ºC and 75 ºC).
PENGARUH KOMPOSISI LAPISAN NI-CR PADA BAJA ASME SA 210 C TERHADAP LAJU EROSI SUHU TINGGI Utomo, Slamet Prasetyo; Darmadi, Djarot B.; Widodo, Teguh Dwi
Jurnal Rekayasa Mesin Vol. 15 No. 1 (2024)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v15i1.1501

Abstract

The purpose of this study was to determine the high temperature erosion rate of the NiCr coating on ASME SA 210 C steel using the combustion oxy fuel thermal spray method. In Circulating Fluidized Bed (CFB) boiler, there is circulation of fly ash, silica sand and air in a high temperature environment which causes erosion. High temperature erosion can be minimized by using Ni-Cr alloy coating sing the combustion oxy fuel thermal spray method. NiCr alloy is proved a able to provider a metal alloy layer composition that can withstand temperatures of 600°C with a fly ash impact speed of 200m/s. The metal alloy compositions that have been studied are NiCr, NiCrCo, NiCrWc, NiCrWcCo, and NiCrCoMo. The results of this study indicates that metal alloys are generally atteche to the substrate and withstand at a high temperatures (600°C). The highest hardness provide by NiCrWcCo alloy which is 177.46 HV. The lowest hardness is found in the composition of the NiCrCo alloy (161.71 HV). The lowest high temperature erosion rate was found in the NiCrWcCo alloy, which was -0.00481 gram/minute. This low erosion rate because the NiCrWcCo alloy produces a good weeting effect for metal alloys and has a high hardness value.
DURASI PERAWATAN OPTIMUM UNTUK FASILITAS PRODUKSI MINYAK DAN GAS DI KILANG TUBAN EAST JAVA Yahya, Indra Nur; Mahatwan, Dian; Setiawan, Ari; Darmadi, Djarot B.
Jurnal Rekayasa Mesin Vol. 15 No. 1 (2024)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v15i1.1839

Abstract

Electric Submersible Pump (ESP) is one of the most critical oil & gas equipment in Tuban East Java (TEJ) field. This research applies Reliability Centered Maintenance (RCM) to oil & gas to optimize maintenance methods for ESP at the TEJ field. The RCM was applied based on the historical failure events at equipment which caused Loss Production Opportunity (LPO). Start with Pareto chart, the RCM followed by Failure Modes and Effect Analysis (FMEA) that produced the Risk Priority Number (RPN) for the 80% problems. The last step provided the optimum maintenance periods using Weibull’s statistic. The result shows that flat cable in ESP has the highest RPN. Flat cable requires an optimum maintenance period of 509 days and a total cost of US$59,342. The total cost consists of Periodic Maintenance (PM) and Risk costs.
Stress analysis of steam turbine rotor using Fluid-Structure Interaction simulation Fauzi, Katanda Fajar; Choiron, Moch. Agus; Widodo, Agung Sugeng; Irawan, Yudy Surya; Darmadi, Djarot B.; Purnowidodo, Anindito
GMPI Conference Series Vol 3 (2024): The 10th Asian Academic Society International Conference (AASIC)
Publisher : Gemilang Maju Publikasi Ilmiah (GMPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53889/gmpics.v3.419

Abstract

Steam Power Plant generates electricity due to a device that extracts heat energy from steam and converts it into mechanical work on the rotor. Turbines operate at high pressures and temperatures which may cause potential failures in the rotor. This study aims to determine the stress distribution on the turbine rotor to predict potential failures. The turbine studied is a 15 MW steam turbine with a rotation speed of 3000 rpm, inlet steam pressure of 2 MPa, and inlet steam temperature of 471.2 OC. The study focused on the Curtis stage. Fluid-Structure Interaction (FSI) simulation was performed to determine the interaction between the fluid and the turbine rotor. Computational Fluid Dynamic (CFD) was performed to determine the temperature and pressure hitting the rotor. The temperature and pressure distribution data from the CFD simulation is transferred to the structural simulation as the load received by the rotor. In addition to fluid loads, the rotor experiences centrifugal loads due to rotation and gravity loads. The largest stress received by the turbine rotor is at the front of the rotor with a stress of 347.39 MPa.
STUDY ON THE SHRINKAGE POROSITY OF AUTOMOTIVE PARTS QUALITY: THE INFLUENCE OF REINFORCED SHELL MOLD THICKNESS IN INVESTMENT CASTING Khoiruddin, Sukhoiri; Darmadi, Djarot B.; Huang, Cheng-Fu; Lee , Sheng-Chan; Chan, Chien-Wei
International Journal of Mechanical Engineering Technologies and Applications Vol. 6 No. 2 (2025)
Publisher : Mechanical Engineering Department, Engineering Faculty, Brawijaya University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/MECHTA.2025.006.02.7

Abstract

This study investigates the effect of shell mold thickness on shrinkage porosity observed through numerical simulation using a computer-aided numerical testing (CAE) approach and testing of mechanical, thermal, and physical properties of shell molds. This study investigated whether the thermal properties of different shell mold layer thicknesses. The results showed that the modulus of rupture (MOR) had a value of 6.66 MPa, the permeability was in the range of 1.8x10-¹² m² to 6.6x10-¹² m², the heat transfer coefficient (HTC) had a value in the range of 900 W/m²-K to 660 W/m²-K. The CAE simulation shows that the initial coating thickness will cause problems in the thick corner area for automotive parts. To reduce the hot spot area is to increase the thickness of the mold shell to reduce the percentage of hot spots, which can reduce the possibility of shrinkage formation by 34% that occurs at a mold shell thickness of 6.5 layers can be reduce about 24% compared shell thickness of 4.5 layers. In this study, the best solution to increase the productivity of investment casting is the selection of mold thickness and here for objects that have high dimensions and accuracy must be correct in determining the use of shell mold thickness because different objects will certainly affect the defects that occur.
Co-Authors Agung Sugeng Widodo Anindito Purnowidodo Ari Setiawan Bintang Rahmaddian Anwari, Bintang Rahmaddian Chan, Chien-Wei Eko Budianto EKO BUDIYANTO Fauzi, Katanda Fajar Halman, Halman Huang, Cheng-Fu Khoiruddin, Sukhoiri Lee , Sheng-Chan Mahatwan, Dian Moch. Agus Choiron Muhammad Ikram Kido Nasmi Herlina Sari Sugiarto S Suteja Suteja, Suteja Teguh Dwi Widodo Utomo, Slamet Prasetyo Yahya, Indra Nur Yudy Surya Irawan