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All Journal Department of Naval Architecture Rekayasa Mesin Jurnal Rekayasa Mesin Journal of Mechanical Engineering Science and Technology SELAPARANG: Jurnal Pengabdian Masyarakat Berkemajuan Angkasa: Jurnal Ilmiah Bidang Teknologi KACANEGARA Jurnal Pengabdian pada Masyarakat Mekanika: Majalah Ilmiah Mekanika Janaka : Jurnal Pengabdian Masyarakat Jurnal Pendidikan dan Teknologi Indonesia Jurnal Ilmiah Wahana Pendidikan Society: Jurnal Pengabdian Masyarakat Jurnal Rekayasa elektrika Jurnal Abdimas Taawun: Jurnal Pengabdian kepada Masyarakat Rekayasa: Jurnal Penerapan Teknologi dan Pembelajaran Jurnal Panjar : Pengabdian Bidang Pembelajaran
Aldias Bahatmaka
Universitas Negeri Semarang
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Economic Empowerment of Indonesian Migrant Workers in South Korea Through Digital-Based Financial Literacy Prajanti, Sucihatiningsih Dian Wisika; Bahatmaka, Aldias; Diantoro, Markus; Pujiarti, Herlin; Retnaningsih, Prihatini
Jurnal Abdimas Vol. 29 No. 1 (2025): June 2025
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/abdimas.v29i1.31052

Abstract

Indonesian Migrant Workers (PMI) contribute significantly to the national economy through remittances, but still face challenges in managing their finances wisely. The low level of financial literacy and limited utilization of digital financial services cause many PMIs to have difficulties in long-term financial planning. This service program aims to empower Indonesian migrant workers in South Korea through digital-based financial literacy training using the Design Thinking approach. Five stages in this method: Empathize, Define, Ideate, Prototype, and Test, are used to design learning media that suits user needs. The results of the activity showed that the developed media, in the form of online modules, leaflets, and training videos, were rated as excellent by experts and migrant practitioners with an average score of 3.71 on a scale of 4. The evaluation also showed that this media is easy to understand, relevant to the needs of migrant workers, and has the potential to be developed sustainably. This service not only improves the financial literacy of migrant workers, but also opens up opportunities for program replication in other migrant communities.
ANALYSIS OF THE THRUST ON PROPELLER SHAFT ANGLE ON FISHING VESSEL USING CFD Prasdika, Tegar Oki; Bahatmaka, Aldias; Andriano, Kriswanto
Jurnal Rekayasa Mesin Vol. 16 No. 2 (2025)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v16i2.2073

Abstract

Indonesian fishing vessels need a prime mover capable of propelling the vessel forward and backward. According to data from the Ministry of Maritime Affairs and Fisheries, many vessels in Indonesia are spread across various State Fisheries Management Areas of the Republic of Indonesia waters. Most of the ships are in the State Fisheries Management Area of the Republic of Indonesia, 712 area, from a total of 4,989 vessels found in the area. This study aims to determine the thrust and torque values generated from the propeller using Ansys CFD (Computational Fluid Dynamics) software to determine the thrust force on the ship. The method used is the operation of the Ansys Fluent program on a computing device to calculate and simulate the effect of thrust on the propeller against the tilt angle of the shafts at 0°, 5°, 10°, 20°, 30°, 40°, 50°, and 60°. Before simulating, a validation process has been performed with an error below 5% in straight conditions without tilt. The results show propellers with various shaft angles have different thrust and torque values. In the simulation of a 50° tilt angle, the thrust value is 55809 N and the torque is 7211.15 Nm, while at a 60° tilt angle, the thrust value is 54582.4 N and the torque is 6193.81 Nm. Therefore, the propeller tilt position of 50° has the appropriate thrust and torque and can produce the optimal thrust force compared to other angles.
Analyzing the Total Resistance and Wave Pattern of Purse Seine Vessels with Photovoltaic-Powered Naryanto, Rizqi Fitri; Bahatmaka, Aldias; Wibowo, Muhammad Yusuf; Ghyferi, Andi Abdullah; Fahmi, Fiqri Fadillah; Hyoung Cho, Joung
Rekayasa Vol. 22 No. 2 (2024)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v22i2.10634

Abstract

With 64.97% of its territory consisting of sea, Indonesia is one of the world's largest maritime nations and produces approximately 8.02 million tons of fish annually. Traditional fishing vessels play a crucial role in supporting livelihoods, yet their design is often based on hereditary methods rather than hydrodynamic optimization. This study uses catamaran hull forms as a design reference to analyze the total resistance and wave patterns of purse seine vessels with photovoltaic-powered systems. Computational methods are employed to predict vessel performance efficiently. The resistance analysis applies the Slender Body approach and Savitsky's mathematical model, supported by comparative studies for validation. Particular attention is given to the influence of chine configurations on resistance characteristics and wave formation. Results indicate that the addition of chines increases the Froude number and contributes to reducing total resistance. Among the variations, single chine geometry demonstrates the lowest resistance, making it the most efficient configuration for catamaran fishing vessels. While chine modifications affect the wave pattern, the hull maintains a relatively clean wake distribution. These findings highlight the potential for improving vessel design through careful chine geometry optimization combined with computational modeling. The study underscores the importance of modern hydrodynamic analysis in advancing traditional fishing vessels toward higher efficiency and sustainability. Future research is recommended to incorporate more advanced computational approaches, such as Computational Fluid Dynamics (CFD), examine water-hull interactions and enhance vessel performance under operational conditions.
Karakteristik Variasi Lateral Tilt Angle pada Friction Stir Welding Material High Density Polyethylene Terhadap Kekuatan Tarik dan Bending Azara, Salsa Bila; Ramadhani, Risky; Budi Darsono, Febri Budi; Bahatmaka, Aldias; Kriswanto, Kriswanto; Firmansyah, Hendrix Noviyanto
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 17, No 2 (2025)
Publisher : Institut Teknologi Dirgantara Adisutjipto

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28989/angkasa.v17i2.3004

Abstract

Friction Stir Welding (FSW) is a solid-state joining method suitable for thermoplastics like HDPE, which has lighter and more flexible properties. This study aims to examine the tensile and bending strength of HDPE joints influenced by parameters such as TRS 930 rpm, a feed rate of 20mm/min, and variations in the Lateral Tilt Angle (LTA) of 0°, 0.5°, 1°, and 1.5°, where the tool's position is sideways relative to the tool's movement direction as the main variable. Resulting in maximum tensile strength (UTS) values of 3.15 MPa, 16.0 MPa, 16.9 MPa, and 8.59 MPa. LTA 1° produced the highest UTS, while LTA 0° produced the lowest UTS because the heat input was not sufficient to perfectly bond the welding material. The bending strength values produced were 4.25 MPa, 14.3 MPa, 4.17 MPa, and 28.8 MPa. The highest stress is found at a 1.5° variation and the lowest at a 1° variation, due to uneven heat distribution during the FSW process. Therefore, choosing the right TLA during the FSW process is key to achieving HDPE joints with good mechanical strength
Efek Sandblasting Terhadap Karakterisasi Pelapisan Coating 95MXC Pada Stainless Steel 304 Menggunakan Metode TWAS (Twin Wire Arc Spray) Puspitasari, Windy Desti; Fitriyana, Deni Fajar; Anis, Samsudin; Bahatmaka, Aldias; Irawan, Agustinus Purna; Siregar, Januar Parlaungan; Cionita, Tezara; Manalu, Janviter
Jurnal Rekayasa Mesin Vol. 19 No. 1 (2024): Volume 19, Nomor 1, April 2024
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v19i1.5392

Abstract

Impeller adalah komponen utama pompa sentrifugal yang sering mengalami kegagalan seperti erosi, korosi dan kavitasi. Untuk mencegah kegagalan tersebut, salah satu cara yang digunakan adalah memberikan pelapis dengan metode TWAS. Pada penelitian yang telah ada, coating dengan metode TWAS menjadi salah satu pilihan yang banyak digunakan, namun belum banyak penelitian yang membahas mengenai pengaruh pengulangan sandblasting pada coating metode TWAS. Penelitian ini bertujuan untuk mengetahui pengaruh pengulangan sandblasting pada impeller pompa berbahan baku stainless steel 304 dengan metode Twin Wire Arc Spray Coating dengan NiAl sebagai bond coat dan FeCrBSiMn sebagai top coat. Penelitian ini menggunakan spesimen tanpa diberikan pelapisan dan spesimen tebaik yakni yang diberi pelapisan dengan satu pengulangan sandblasting. Karakterisasi dilakukan untuk mengetahui kekasaran permukaan (ISO 8503), kekerasan lapisan (ASTM E384), coating (ASTM D4541), dan laju korosi (ASTM G102). Pengujian SEM dan analisis ImageJ dilakukan untuk mengetahui struktur lapisan. Hasil penelitian menunjukan sandblasting dengan satu pengulangan memiliki hasil kekasaran permukaan dan ketebalan lapisan terendah. Namun, memiliki hasil karakterisasi lapisan paling optimal dengan porositas dan unmelt terendah, kekerasan tertinggi dengan 1081.6 HV dengan coating yang sudah sesuai dengan standar yakni 14.5 MPa dan semakin banyak pengulangan sandblasting, semakin tinggi laju korosinya. Kesimpulan dari penelitian ini adalah satu pengulangan sandblasting dalam metode TWAS sudah memberikan kualitas terbaik yang dapat meningkatkan performa dan penggunaan impeller pompa.
Optimization Design of NACA 4412 Airfoil Based on Genetic Algorithm for Efficiency and Maximum Lift Force Laksono, Aryo Eko; Bahatmaka, Aldias; Fitriyana, Deni Fajar; Laksono, Galih Tri; Habibullah, Muhammad; Nubli, Haris; Hyung, Cho Joung
Jurnal Rekayasa Mesin Vol. 20 No. 2 (2025): Volume 20, Nomor 2, Agustus 2025
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v20i2.6531

Abstract

The NACA 4412 airfoil, renowned for its exceptional subsonic aerodynamic performance, faces critical operational constraints including elevated drag characteristics and premature stall onset at high angles of attack. While previous investigations have independently examined internal slot modifications and gurney flap implementations for aerodynamic enhancement, the synergistic potential of their combined application to the NACA 4412 configuration remains largely unexplored. This research presents a comprehensive optimization study that strategically integrates internal slot geometry with gurney flap configuration to maximize lift coefficient (CL) and aerodynamic efficiency (CL/CD) through advanced genetic algorithm optimization. The methodology employed high-fidelity computational fluid dynamics simulations using FLUENT with Spalart-Allmaras turbulence modeling, validated against experimental data to ensure accuracy. PCHIP numerical interpolation techniques were utilized to estimate aerodynamic coefficients across comprehensive angle-of-attack ranges not directly simulated. The optimized configuration demonstrated remarkable performance improvements, including a 75.68% increase in lift coefficient, an extension of the critical stall angle from 14° to 16°, enhanced aerodynamic efficiency, and significantly improved flow stability with reduced separation characteristics. These findings establish that the synergistic combination of internal slot and gurney flap modifications can fundamentally transform NACA 4412 aerodynamic performance, particularly excelling in high-angle-of-attack operational scenarios.
Robust Stochastic Model Predictive Control for Autonomous Vehicle Motion Planning Subiyanto, Subiyanto; Hangga, Arimaz; Bahatmaka, Aldias; Salim, Nur Azis; Sutrisno, Deyndrawan; Yunus, Elfandy; Budi Arif Prabowo, Setya; Hilmi Farras, Muhammad; Sanggrahita, Diadora
Jurnal Rekayasa Elektrika Vol 20, No 3 (2024)
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17529/jre.v20i3.39281

Abstract

This work presents a Robust Stochastic Model Predictive Control (RSMPC) framework for real-time motion planning autonomous vehicles, addressing the complex multi-modal vehicle interactions. The proposed framework involves adding expert policy from observations to the dataset and applying the Data Aggregation (DAgger) method to filter unsafe demonstrations and resolve expert conflicts. A Dual-Stage Attention-based Recurrent Neural Network (DA-RNN) model is integrated to predict dual class variables from the dataset, producing a set containing constraints collision-avoidance predicted to be active. The RSMPC framework enhances formulation optimization by eliminating irrelevant collision avoidance constraints, resulting in faster control signals. The framework is applied iteratively, continuously updating observations and solving the RSMPC optimization formulation in real-time. Evaluation of the DA-RNN model achieved a recall value of 0.97 and a high accuracy rate of 98.1% in predicting dual interactions, with a minimal false negative rate of 0.026, highlighting its effectiveness in capturing interaction intricacies. Validated through simulations of interactive traffic intersections, the proposed framework demonstrably excels, showing high feasibility of 99.84% and a 15-fold increase in response speed compared to the baseline. This approach ensures autonomous vehicles navigate safely and efficiently in complex traffic scenarios, paving the way for more reliable and scalable autonomous driving solutions.
Penerapan teknologi pengering pelet untuk peningkatan kualitas dan produksi pakan ternak di CV Sibad Engineering Semarang Bahatmaka, Aldias; Fitriyana, Deni Fajar; Darsono, Febri Budi; Wibowo, Muhammad Yusuf; Fahmi, Fiqri Fadillah; Hidayat, Indra Nurul; Buana, Lanang Puspa; Ghyferi, Andi Abdullah
KACANEGARA Jurnal Pengabdian pada Masyarakat Vol 8, No 1 (2025): Februari
Publisher : Institut Teknologi Dirgantara Adisutjipto

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28989/kacanegara.v8i1.2576

Abstract

Pakan ternak merupakan faktor terbesar yang mempengaruhi produktivitas ternak. Dalam hal ini, mitra masih mengalami kendala dalam proses pengeringan pelet sebagai pakan ternak. Hal yang masih dilakukan dengan melakukan proses pengeringan pakan ternak terdahulu yaitu masih dilakukan secara konvensional dengan dijemur dibawah terik sinar matahari, sehingga tidak efektif dalam mengeringkan pakan ternak. Oleh karena itu perlu penerapan teknologi pengeringan dari hasil pengolahan pakan ternak menggunakan mesin rotary dryer. Mesin pengering dengan rotary dryer ini, pakan ternak dapat dikeringkan menggunakan drum pengering yang terbuat dari baja tahan karat dan dengan sistem kontrol komponen PLC. Hasil pengeringan menggunakan mesin pengering rotary dryer dihasilkan dalam bentuk serbuk atau butiran. Penerapan teknologi mesin rotary dryer ini dirancang untuk mencapai beberapa tujuan, termasuk meningkatkan efisiensi pengeringan pakan ternak dan meningkatkan kualitas dan produksi pakan ternak. Penerapan teknologi mesin pengering rotary dryer ini diharapkan dapat meningkatkan kualitas dan produksi pakan ternak di CV SIBAD Engineering Semarang.
NUMERICAL ANALYSIS OF MOUNTING BRACKET STRUCTURE ON THE DAMPING EFFECT OF STABILIZER STEERING DAMPERS Wibowo, Muhammad Yusuf; Bahatmaka, Aldias; Rusiyanto, Rusiyanto; Fitriana, Deni Fajar; Ghyferi, Andi Abdullah; Anwar, Ahmad; Ridananda, Ayyub; Chasan, Ahmad
Jurnal Rekayasa Mesin Vol. 16 No. 1 (2025)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v16i1.1657

Abstract

Due to bumps or holes in the road, certain regions' road surface is still unsuitable for riding at high speeds. Many motorcycles used stabilizer steering dampers to reduce weave and wobble. Bracket is a structure that holds the stabilizer steering dampers to the motorcycle steering. Bracket plays a significant role in maintaining the stabilizer steering dampers as well as stopping any vibration due to the dynamic conditions. This paper presents Finite Element Analysis of a bracket, which is analyzed material aluminum 6061 and aluminum alloy cast. In this study, we have explored using Static Analysis to calculate the internal force, displacement, and stress of structural brackets. Hence in this study, we have performed Modal Analysis to determine the natural frequencies of the bracket for safety. And also, we have performed Transient Analysis to study the behavior of structure brackets over time in response to time-varying loads and vibrations in dynamic conditions.
PENGARUH MATERIAL TERHADAP DEFORMASI, STRAIN, DAN SAFETY FACTOR PADA BRACKET CALIPER MENGGUNAKAN METODE ELEMEN HINGGA Ghyferi, Andi Abdullah; Bahatmaka, Aldias; Wibowo, Muhammad Yusuf; Anwar, Ahmad; Ridananda, Ayyub; Vandika, Anggi
Jurnal Rekayasa Mesin Vol. 15 No. 3 (2024)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v15i3.1700

Abstract

The purpose of this study is to analyze the deformation, equivalent elastic strain, and safety factor of a bracket bracket made from two different materials by using the Finite Element Method, specifically aluminum alloy 6061 T6 and cast iron EN GJL 100. The result of this study is that the Aluminum Alloy 6061T6 material has a deformation of 3.57E-04 whereas the Cast iron EN GJL 100 material is 2.75E-04. In the elastic strain equivalent test, the Aluminium alloy 6061 T6 material is 3.00-E07 and in the Cast Iron EN G JL 100 materials is 2.32E-07. In the safety factor test, Cast Iron En G J L 100 material was better than 1.8617 compared to the Alumium Alloys 60 61 T6 materials are 1.5125. This shows that Cast Iron E GJ L 100 materials are better in deformations, eqeuivalent elastic stations, and safety factors in this case.
Co-Authors Abdurrahman Abdurrahman Agustinus Purna Irawan Andi Abdullah Ghyferi Andriano, Kriswanto Anindya Ardiansari Anwar, Ahmad Ari Dwi Nur Indriawan Musyono Arimaz Hangga, Arimaz Arrijah, Hanalinda Kubrus Asri, Sarwi Azara, Salsa Bila Buana, Lanang Puspa Budi Arif Prabowo, Setya Budi Darsono, Febri Budi Chasan, Ahmad Cho, Joung Hyung Cionita, Tezara Darsono, Febri Budi Didik Supriadi Dony Hidayat Al-Janan Eko Sasmito Hadi Fahmi, Fiqri Fadillah Fidia Fibriana Fiqri Fadillah Fahmi Fitriana, Deni Fajar Fitriyana, Deni Fajar Ghyferi, Andi Abdullah Godham Eko Saputro Hanif Hidayat Hendrix Noviyanto Firmansyah, Hendrix Noviyanto Herlin Pujiarti Hidayat, Hanif Hidayat, Indra Nurul Hilmi Farras, Muhammad Hutagalung, Christian Imanuel Hyoung Cho, Joung Hyung, Cho Joung Imam Pujo Mulyatno Imanu Danar Herunandi Indah Anisykurlillah Irawaty Irawaty Iskandar, Ranu Karnowo - Khoirul Huda Kriswanto Kriswanto, Kriswanto Kurniawan, Ahmad Khusom Kusuma, Anwar Widjaya Laksono, Aryo Eko Laksono, Galih Tri Leksono, Panggah Bowo M. Harlanu, M. Manalu, Janviter Markus Diantoro Mayangsari , Effelie Dewi Mera Kartika Delimayanti Muhammad Habibullah Muhammad Khumaedi Muhammad Yusuf Wibowo Natalia Desy Putriningtyas, Natalia Desy Nubli, Haris Prasdika, Tegar Oki PUDJI ASTUTI Puspitasari, Windy Desti Puteri, Berliana Ayarent Putrananda , Musdika Bagas Satria Putrananda, Musdika Bagas Satria Rafif Dimas Pratama Ramadhani, Risky Retnaningsih, Prihatini Ridananda, Ayyub Rizki Setiadi Rizqi Fitri Naryanto Rumapea, Fedrik Immanuel Rumondang, Juwita Ria Rusiyanto Rusiyanto, Rusiyanto Salim, Nur Azis Samsudin Anis Sandi Pratama , Fajar Rizqi Sanggrahita, Diadora Sari, Linda Setiadi, Rizki Siregar, Januar Parlaungan Sonika Maulana Sucihatiningsih Dian Wisika Prajanti Sukoco, Imam Sunyoto Sunyoto Supriadi, Didik Sutrisno, Deyndrawan Syafei, M. Hilman Gumelar Vandika, Anggi Wara Dyah Pita Rengga Warsiti Warsiti Warsiti Warsiti Wibowo, Muhammad Yusuf Widya Aryadi Widya Hary Cahyati Winarko, Chandra Adi Won, Lee Sang Yunus, Elfandy