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All Journal KAPAL Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Department of Naval Architecture Jurnal Teknosains Rekayasa Mesin International Journal of Marine Engineering Innovation and Research
Ahmad Firdhaus
Department Of Naval Architecture, Faculty Of Engineering, Diponegoro University, Semarang
Automotive Engineering Biochemistry, Genetics & Molecular Biology Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Transportation

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Benchmark Study of FINETM/Marine CFD Code for the Calculation of Ship Resistance Firdhaus, Ahmad; Suastika, I Ketut; Kiryanto, Kiryanto; Samuel, Samuel
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 18, No 2 (2021): June
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v18i2.39727

Abstract

Benchmarking can be used to test CFD programs for selecting turbulence models, grid dependency studies, testing different numerical schemes and source codes, and testing different boundary conditions. CFD simulation in this study uses FINE™/Marine 7.2-1 software. The solver process at NUMECA uses the ISIS-CFD flow solver developed by EMN, which uses the incompressible unsteady Reynolds-average Navier stoke equation (RANSE). The solver is based on the finite volume method, and Turbulence models use SST k-ω models. The free surface flow around a model surface ship (DTMB 5415) advancing in calm water under steady conditions is numerically simulated. The geometry of the DTMB 5415 ship hull was provided in igs file format. The 1996 International Towing Tank Conference has recommended the DTMB 5415 combatant as a benchmark case for CFD computations of ship resistance and propulsion. The results compare well with the available experimental data. They allow an understanding of the differences that can be expected from vicious and potential flow methods due to their different mathematical formulations. It is demonstrated that the complementary application of these methods allows good predictions of the total ship resistance.
Comparative Analysis of Slamming Phenomenon Prediction between U and V Hulls using Strip Theory Method Muhammad Luqman Hakim; Ahmad Firdaus; Gita Marina Ahadyanti; Totok Yulianto
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 19, No 3 (2022): October
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v19i3.46805

Abstract

Choosing the right hull shape is important in designing a ship, for example, a U-section or V-section of the hull. The hull shape will affect various aspects, such as design, resistance, seakeeping, structure and production. The ship hull must be properly designed so that it can operate according to the ship’s mission. From the seakeeping aspect of the ship's motion at sea, the difference in the hull shape will result in different motions and dynamic effects such as the slamming phenomenon. Based on the difference in the hull shape cases, this study analyzed the difference in the probability of slamming between the U and V hulls. Both hulls were made based on Formdata and almost all parameters were made the same. Parameters that cannot be forced to be the same are WSA (wetted surface area),  (coefficient of waterplane area), and  (distance of keel to buoyancy), where those parameters determine the difference in the results. The calculation of RAO (operator amplitude response) was obtained using the strip theory method which assisted by Maxsurf Motion software. The results became the input for the calculation of the slamming probability. The study results show that the U hull has a higher probability of slamming occurrence than that of the V hull, with the difference in values ranging from 20% to 35%. Therefore, the U hull will get more frequent slamming loads, so it has the potential to have a higher structural failure (fatigue) than that of the V hull.
Passengers and Crew's Evacuation from Passenger Ships Under Fire: An Agent-Based Model Simulation Study Ahmad Firdhaus; Imam Pujo Mulyatno; Muhammad Luqman Hakim; Zen Zen
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 20, No 1 (2023): February
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v20i1.50714

Abstract

The characteristics of the passengers have a significant impact on how the evacuation procedures are carried out. During an evacuation, the amount of time it takes depends on how quickly passengers move. There is a correlation between age and travel speed, but not always. As a result of this problem, a significant number of passengers were unable to make it to the assembly point in time for the evacuation, which may have resulted in fatalities. An evacuation simulation will be carried out aboard passenger ships in the event of a fire. This research will employ agent-based modeling to perform the simulation, and it will include modifications for day and night, as well as for the number of emergency stairs used. The findings of this study are the simulation times for the evacuation of passengers and crew for each scenario, with the shortest time for evacuation occurring during the daytime with operational emergency stairs, clocking in at 36.51 minutes, and the longest time for evacuation occurring during the night with damaged emergency stairs, clocking in at 47.43 minutes. Both times are given in minutes. According to the findings, the evacuation circumstances satisfied the standards set by the IMO, which demanded that the entire amount of time spent evacuating be less than or equivalent to sixty minutes
Effects of Collision with a Self-Propeller Oil Barge Ship on a Navigational Buoy Wilma Amir Amiruddin; Ahmad Firdhaus; Hartono Yudo; Firmansyah Aulia Rakhman
International Journal of Marine Engineering Innovation and Research Vol 8, No 2 (2023)
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v8i2.16324

Abstract

A navigation buoy is a navigational aid tool that is very important in supporting the safety of shipping lanes. However, navigation buoys are often lost and damaged, caused by several factors, one of which is being hit by a ship. Therefore, it is essential to conduct this research to determine the damaging effect on the navigation buoy after being hit by a vessel and to determine the effectiveness of using medium-density polyethylene material in the navigation buoy structure. This study uses a finite element numerical simulation method by making three variations of speed, as well as two variations of the angle of impact, namely 0° and 45°, which lasted for 0.1 seconds and was assisted by FEA software. The simulation results indicate that the largest maximum deformation occurs when the ship strikes the buoy with a speed of 7 m/s at an angle of 0° of 0.6 m. In this scenario, there is also a significant damage condition that results in tearing the buoy shell's surface by as many as 413 elements, or 1.24 m. The most extraordinary kinetic and internal energy produced occurred at a speed of 7 m/s with an angle of 45° of 147.15 kJ and 45.70 kJ. Therefore, it can be stated that the amount of buoy damage caused by a ship collision is dictated or impacted by the starting speed of the ship and the angle of impact state the most important part of your findings and achievements
IMO-COMPLIANT ANALYSIS OF THE LARGE ANGLE STABILITY OF CHEMICAL TANKERS DURING THE LOADING AND UNLOADING LIQUID CAUSTIC SODA Firdhaus, Ahmad; Pujo, Mulyatno Imam; Luqman, Hakim Muhammad; Sekar, Wangi Nimas Ayu
Jurnal Rekayasa Mesin Vol. 14 No. 3 (2023)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v14i3.1409

Abstract

MT. Sinar Masela 8831 DWT is a ship transporting oil and chemicals certified by IMO Chemical Class 2,3. According to Chapter B, SOLAS CHAPTER VII, regarding water safety, loading and unloading oil and chemicals is categorized as dangerous due to water damage and pollution. Various studies are needed to expedite the loading and unloading process to reduce damage and pollution in the waters. One of these studies is regarding the stability of ships in accordance with IMO criteria. The study was conducted to determine the ship stability on the MT. Sinar Masela is in the loading-unloading process. This study applies eight conditions with seven-compartment tanks on the ship using software to analyze the stability calculation when the loading-unloading process meets the stability criteria set by IMO A.749(18) Ch 3. The results show the measure of stability in eight conditions with a seven-compartment tank during the loading and unloading process has a higher GZ value in all states, which has met the IMO stability criteria. Comparison of stability calculations on loading and unloading has an average difference of 0.226 m at 2.075 deg at the GZ value in each condition.
CFD Analysis of Interference Factor in Hydrofoil-Supported Catamarans (HYSUCAT) Firdhaus, Ahmad; Kiryanto, Kiryanto; Rindo, Good; Trimulyono, Andi
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 21, No 1 (2024): February
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v21i1.61750

Abstract

Catamaran, with its distinctive dual-hull design, offers unique advantages in maritime applications, including improved stability and space utilization over traditional monohull vessels. However, the interaction between the two hulls generates complex hydrodynamic phenomena, significantly influencing the vessel's overall performance. One critical aspect of this interaction is the interference factor, which affects the hydrodynamic resistance encountered by the vessel. The purpose of this paper is to investigate the changes in hydrodynamic characteristics that occur when hydrofoils are incorporated into typical catamaran hull forms. This is accomplished through the utilization of advanced Computing Fluid Dynamics (CFD) simulations. In this study, a Delft-372 catamaran with a concept design is modified by installing a foil system with a high Reynolds number in order to reduce its overall resistance. The new system is then analyzed in order to determine the impact that it has on interference factors. For the purpose of achieving a comprehensive understanding of hydrodynamic behavior, the simulations are carried out under a variety of operating conditions, which include a variety of speeds. Simulations result indicate that the interference factor consistently increases drag for hydrofoil-supported catamarans to more than double that of monohulls across all speeds, particularly when hydrofoil-induced flow disturbances adversely affect the hull's boundary layer, leading to reduced efficiency.
Impacts of temperature and coating pigment ratios on the corrosion rate of ss400 steel Budiarto, Untung; Firdhaus, Ahmad; Hakim, Muhammad Luqman; Tuswan, Tuswan; Yusuf, Fauzan Ammar Fata
Jurnal Teknosains Vol 13, No 2 (2024): June
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/teknosains.85518

Abstract

Steel is the primary shipbuilding material; however, it erodes quickly. Adequate protection requires hard, durable, and adhesive coatings. This study examines how aluminium-graphite pigment and heat treatment affect epoxy-coated SS400 steel plate corrosion, adhesion, and coating resilience. This study used a 1:1 and 3:1 pigment ratio with 100°C and 150°C heat treatment. The coating layer was 250 μm thick and comprised 80% epoxy and 20% aluminum-graphite. The maximum adhesion strength, 19.62 MPa, was achieved with an aluminium-graphite pigment ratio of 1:1 and 100°C heat treatment. The top coating resistance was 6.86 Joules under identical conditions. The lowest corrosion rate, 0.047 mmpy, was at a 3:1 aluminum-graphite ratio and 150°C heat treatment. This discovery has significant consequences for shipbuilding steel corrosion resistance.
Karakterisasi Sifat Fisis dan Mekanis Besi Cor FCD 45 untuk Kelayakan sebagai Bahan Baku Jangkar Kapal Hendriyanto, Heri; Sisworo, Sarjito Joko; Firdhaus, Ahmad
Jurnal Teknik Perkapalan Vol 12, No 1 (2024): Januari
Publisher : Diponegoro University

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Abstract

Besi Cor FCD 45 berpotensi untuk dijadikan bahan baku jangkar, oleh karena itu perlu dilakukan karakterisasi. Karakterisasi sifat fisis adalah sifat yang berhubungan dengan elemen penyusun logam sedangkan karakterisasi sifat mekanis adalah sifat dari struktur logam jika dikenai gaya atau tekanan secara mekanis. Penelitian ini bertujuan apakah besi cor FCD 45 layak untuk bahan baku pembuatan jangkar kapal sehingga perlu dilakukan beberapa pengujian. Pengujian besi cor FCD 45 terdiri dari uji tarik, uji impak, uji kekerasan dan mikrografi. Hasil rata-rata tegangan tarik adalah 481,3 MPa. regangan tarik 0,9%, dengan modulus elastisitas 72,48 GPa. Rata-rata nilai impak didapat setelah memperhatikan standar deviasi adalah 0,072 MPa. Pada uji mikrografi matrik yang terbentuk yaitu ferrit dan perlit, dimana matrik ferrit lebih banyak dibandingkan dengan matrik perlit sehingga sifat material cenderung ulet dan tidak memiliki kekerasan yang tinggi. Nilai rata-rata kekerasan setelah memperhatikan standar deviasi adalah 241,33 HV. Jika hasil tersebut dibandingkan dengan aturan BKI maka besi cor FCD 45 tidak memenuhi untuk pembuatan jangkar.
Analisis Antrian dan Waktu Tunggu Terminal Peti Kemas Semarang Arrasyid, Fikri; Amiruddin, Wilma; Firdhaus, Ahmad
Jurnal Teknik Perkapalan Vol 11, No 3 (2023): Juli
Publisher : Diponegoro University

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Abstract

Waktu tunggu kapal diartikan sebagai jumlah waktu yang dihabiskan sejak permohonan pengajuan tambat setelah kapal tiba di lokasi pelabuhan sampai kapal di gerakkan menuju tambatan. Peningkatan arus peti kemas di Terminal Peti Kemas Semarang (TPKS) per tahunnya berbanding lurus dengan peningkatan jumlah kapal yang dapat menimbulkan antrian kapal apabila tidak dilakukan penyesuaian pada fasilitas pelabuhan. Tujuan penelitian ini adalah untuk menganalisis antrian kapal yang terjadi di Terminal Peti Kemas Semarang (TPKS) pada kondisi aktual serta kondisi mendatang serta simulasi untuk menentukan jumlah server paling optimal. Model antrian yang berlaku di Terminal Peti Kemas adalah model Multiple Channel Single Phase. Penelitian ini menggunakan 2 metode analisis, yaitu metode peramalan dengan menggunakan Triple Exponential Smoothing untuk mengetahui jumlah kedatangan kapal di masa mendatang serta metode analisis antrian untuk mengetahui waktu tunggu dan utilitas server antrian yang terjadi di Terminal Peti Kemas Semarang pada kondisi aktual serta kondisi mendatang. Berdasarkan hasil analisis antrian pada Terminal Peti Kemas Semarang (TPKS) jumlah server paling optimal untuk menampung kedatangan kapal hingga tahun 2026 adalah 5 server.
Analisis Hull Strength Kapal Ikan 5 GT Bahan Fiberglass Menggunakan Metode Elemen Hingga Purba, Siska Dearni Ajijah; Mulyatno, Imam Pujo; Firdhaus, Ahmad
Jurnal Teknik Perkapalan Vol 12, No 2 (2024): April
Publisher : Diponegoro University

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Abstract

Hull Strength pada kapal ikan 5 GT bahan fiberglass yang memiliki laminasi CSM 300, CSM 450, dan WR 800 menurut BKI memiliki tegangan ijin bahan 9,80E+07 N/m2 dan modulus elastisitas 72,3 GPa. Analisis penelitian ini berfokus pada perhitungan kondisi torsional, sagging dan hogging kapal dengan kondisi gelombang trochoid tertinggi h = 0,55 m. Perhitungan menggunakan simulasi numerikal  Metode Elemen Hingga untuk mengidentifikasi area kritis yang rentan terhadap tekanan tinggi pada lambung kapal. Dari hasil perhitungan Analisa menggunakan Metode Elemen Hingga, menunjukkan bahwa pada kondisi torsional kapal mengalami tegangan maksimal sebesar 1,75E+07 N/m2 yang lokasinya berada dibagian depan dan belakang, kemudian pada kondisi sagging kapal mengalami tegangan maksimal sebesar 2,34E+07 N/m2 yang lokasinya berada di midship kapal, dan pada kondisi hogging kapal mengalami tegangan maksimal sebesar 2,32E+07 N/m2 yang terjadi pada ruang palka ikan 1. Melalui perhitungan factor of safety, didapat nilai tegangan maksimum yang berada dibawah tegangan ijin dan tegangan bahan yang telah ditetapkan oleh BKI, kemudian didapat pula validasi model sebesar dengan persentase validitas sebesar 94,27 %. 
Co-Authors Andi Trimulyono Arrasyid, Fikri Firmansyah Aulia Rakhman Gita Marina Ahadyanti Good Rindo Hartono Yudo Hendriyanto, Heri I. K. Suastika Imam Pujo Mulyatno Imam Pujo Mulyatno Kiryanto Kiryanto Luqman, Hakim Muhammad Muhammad Luqman Hakim Muhammad Luqman Hakim Pujo, Mulyatno Imam Purba, Siska Dearni Ajijah Samuel Samuel Sarjito Joko Sisworo Sekar, Wangi Nimas Ayu Totok Yulianto Tuswan Tuswan Untung Budiarto Wilma Amiruddin Yusuf, Fauzan Ammar Fata Zen Zen