R.E.M. (Rekayasa Energi Manufaktur) Jurnal

Methods and Characteristics of Quality Control of Composite Materials

2025-03-26T08:31:15+00:00

In modern industry, the demand for high-quality and reliable composite materials is increasing day by day. Ensuring the required operational properties of these materials directly depends on the methods and characteristics of their quality control. This article provides detailed information on the main and general directions of modernization programs adopted in our country, including the improvement of standard requirements, innovative, convenient, and at the same time high-performance methods of quality control and testing of composite materials. In particular, special attention is paid to the introduction of modern equipment and technologies, as well as the effective use of local raw materials and production capabilities[1,4].

Today, the development and improvement of non-destructive testing methods, precision measurement technologies, and automatic quality control systems for composite materials is becoming increasingly important. The use of ultrasonic, radiographic, thermal, optical, and electromagnetic control methods makes it possible to detect internal defects in materials, evaluate their physical and mechanical properties, and monitor the stability of technological processes. In addition, the introduction of digital technologies, artificial intelligence, and modern software complexes ensures the objectivity and accuracy of control results[2,3].

The article also analyzes international experience in ensuring the quality and reliability of composite materials, the role of certification and standardization processes, and the importance of creating regulatory frameworks adapted to the requirements of global markets. As a result, the formation of a comprehensive quality control system covering all stages — from raw material selection to final product testing — is of great importance in increasing the competitiveness of domestic composite materials and expanding their application fields

Windshield Damage Analysis on ATR 42/72-600 Aircraft at PT. DEF

2025-03-26T08:30:54+00:00

Windshield damage on ATR 42/72-600 aircraft at PT. DEF has caused operational disruptions, including flight delays, increased maintenance costs, and potential safety risks. Repeated damage to the Windshield is caused by various factors, namely inspection and maintenance errors, improper installation procedures, damage to the heating system or pressure distribution, glass material degradation, and exposure to extreme weather and UV rays. In this study, the analysis was carried out using a quantitative method with a fishbone diagram to identify the main causes of damage and appropriate mitigation steps. The results of the analysis showed that the main factors contributing to the damage were errors in inspection, installation errors, and material degradation. After implementing mitigation steps such as improving technician training, revising maintenance procedures, and improving material selection, there was a significant decrease in the frequency of Windshield damage. An indication of the success of these mitigation steps can be seen from the repairs carried out during January to June 2024 which succeeded in reducing damage and rejects on the Windshield by 40% compared to 2023, improving the quality of maintenance, inspection and material durability. In terms of maintenance costs for spare parts, there is a decrease in spending on purchasing spare windshields, namely USD 15,375 (PPG Inc.) x 10 units = USD 153,750 in 2023 to USD 21,915 (Saint Gobain) x 3 units = USD 65,745 in 2024 (June), which is 42% until mid-2024. This step increases operational reliability, cost efficiency, flight safety, and employee productivity, customer satisfaction also increases along with reduced flight delays and cancellations due to technical problems. Overall, the study succeeded in reducing Windshield damage and increasing the company's operational efficiency and reliability

Analysis of Pitch Angle Optimization on Horizontal Axis Wind Turbine to Increase the Coefficient of Power (Cp) Value by Simulation and Experiment

2025-03-28T02:58:30+00:00

Energi terbarukan merupakan isu yang sangat penting pada saat ini. Penggunaan pembangkit listrik berbahan bakar fosil harus dikurangi secara sistematis agar tidak memberikan pencemaran lingkungan. Turbin angin merupakan salah satu pembangkit listrik energi terbarukan. Namun demikian penelitian tentang turbin angin harus senantiasa ditingkatkan karena turbin angin memiliki efisiensi yang terbatas. Tidak seperti mesin pada umumnya yang mana efisiensinya cukup tinggi. Penelitian ini bertujuan melakukan optimasi sudut pitch pada turbin angin sumbu horizontal untuk meningkatkan nilai coefficient of power (Cp) secara simulasi dan eksperimental. Optimasi ini harus dilakukan agar gaya lift yang terjadi pada bilah turbin angin sumbu horizontal memiliki nilai optimum dengan memperhatikan gaya drag yang terjadi. Sudut pitch pada turbin dibuat bervariasi dari posisi dekat hub sampai dengan posisi tip. Ada tiga jenis variasi yang dilakukan yaitu 20⁰-0⁰, 25⁰-5⁰ dan 30⁰-10⁰. Simulasi dilakukan dengan software Qblade pada tiga jenis variasi itu kemudian dilakukan eksperimen di laboratorium. Hasil simulasi dan eksperimen menunjukkan pada variasi 20-0 memiliki efisiensi paling tinggi dibanding yang lain. Hasil ini merupakan rekomendasi pada proses pembuatan bilah turbin angin sumbu horizontal.

Optimization of Steam Methane Reforming Process Through Addition of Hydrogen Gas to Hydrogen Plant in Oleochemical Industry

2025-03-31T08:36:51+00:00

Steam Methane Reforming (SMR) merupakan teknologi produksi hidrogen yang beroperasi pada suhu 750-900°C menggunakan katalis berbasis nikel dengan sifat sangat endotermik. Penelitian ini mengkaji pengaruh penambahan hidrogen pada umpan sebagai alternatif optimasi proses di PT Ecogreen Oleochemicals Batam, merespons perubahan komposisi gas alam dari 86% menjadi 82% metana dan peningkatan etana-propana. Perubahan ini menyebabkan ketidakstabilan proses dan pembentukan karbon yang berlebih, mengakibatkan deaktivasi katalis ketika peningkatan rasio steam-to-carbon tidak memungkinkan karena keterbatasan operasional. Hasil penelitian menunjukkan korelasi antara suhu reformer, konsumsi bahan bakar NG, dan yield produk. Penambahan hidrogen terbukti efektif mencegah pembentukan karbon dan mempertahankan stabilitas proses. Studi ini memberikan solusi praktis untuk optimasi produksi hidrogen melalui keseimbangan penambahan hidrogen, suhu reformer, dan efisiensi bahan bakar.

Analysis of the Effect of Wind Speed on the Formation of Porosity Defects in GTAW Welding with Grade A Plate Material and ER70S-G Electrodes

2025-04-29T01:58:32+00:00

Porosity merupakan salah satu cacat las yang dapat mempengaruhi kualitas dan kekuatan hasil pengelasan. Salah satu faktor eksternal yang berkontribusi terhadap munculnya porosity adalah kecepatan angin selama proses pengelasan. Penelitian ini bertujuan untuk menganalisis pengaruh variasi kecepatan angin terhadap pembentukan cacat porosity pada hasil pengelasan GTAW (Gas Tungsten Arc Welding) menggunakan material pelat baja grade A dan elektroda ER70S-G. Eksperimen dilakukan dengan memvariasikan kecepatan angin pada nilai 0 m/s, 2 m/s, 4 m/s, dan 6 m/s menggunakan kipas angin industri yang diatur pada jarak 1 meter dari titik pengelasan. Spesimen uji berupa pelat baja grade A ketebalan 10 mm disambung menggunakan metode pengelasan GTAW dengan parameter arus 160 A, voltase 20 V, dan kecepatan pengelasan 2 mm/s. Pengamatan cacat porosity dilakukan melalui pengujian radiografi. Hasil penelitian menunjukkan bahwa peningkatan kecepatan angin berbanding lurus dengan jumlah dan ukuran porosity yang terbentuk. Pada kecepatan angin 0 m/s, tidak ditemukan cacat porosity yang signifikan. Seiring peningkatan kecepatan angin, jumlah porosity meningkat secara signifikan, dengan cacat terbanyak ditemukan pada kecepatan 6 m/s dengan rata-rata diameter porosity mencapai 2,5 mm. Analisis statistik menunjukkan korelasi positif kuat (R² = 0,92) antara kecepatan angin dan pembentukan porosity. Penelitian ini menyimpulkan bahwa kecepatan angin memiliki pengaruh signifikan terhadap kualitas hasil pengelasan GTAW, dengan batas kecepatan angin maksimal yang direkomendasikan adalah 2 m/s untuk meminimalkan pembentukan cacat porosity.

Analysis of Power Transformer Core Retaining Plate Damage During Ship Transportation Using Response Spectrum Method

2025-05-03T08:33:28+00:00

Inti transformator daya diletakan di dalam tangki dengan kondisi pressfit 4 sisi di bagian dasar tangki dan 4 bagian sisi atas ditopang dari 4 arah terhadap gerakan longitudinal - transversal kemudian 2 pedestal atas inti transformer ditekan dengan tutup tangki di bagian bawahnya. Pada waktu transportasi di laut transformator ini mengalami impak yang terekam sebesar 4.1g, kemudian dengan penyidikan visual terlihat lepasnya pelat penahan dan inti transformator mengalami pergeseran dan kerusakan sehingga transformator harus dimanufaktur kembali di pabriknya. Analisa dinamika menggunakan metoda elemen hingga (finite element method) diperlukan untuk mengetahui apakah kegagalan penopang sudah terjadi di atas nilai percepatan 1g, sehingga nilai 4.1g adalah benturan inti transformator ke tangkinya. Pemodelan dibuat 3D shell wall modeling orisinil untuk penopang dan tangki, sedangkan model inti transformator bentuknya disederhanakan menjadi kotak shell untuk memudahkan meshing. Parameter input menggunakan High Required Response Spectrum 0.5g dari IEEE std 693-2005 sedangkan parameter dinamik yang diukur adalah besarnya ragam getar, fenomena resonansi dan tegangan (stress) pelat. Hasil data analisa dinamik dengan menggunakan metoda elemen hingga yaitu transformator mengalami resonansi dengan dek kapal, atau bila terjadi impak di badan kapal akibat goyangan ombak di percepatan di atas 1g maka pelat penahan telah mengalami tegangan di atas kekuatan tariknya (Tensile Strength).

Tensile Strength and Microstructure Analysis of HDPE and PP Plastic Waste-Based Composites with Cassava Pulp Filler

2025-05-05T07:50:09+00:00

Waste is unused material from human or industrial activities. High Density Polyethylene (HDPE) is a safe plastic, while Polypropylene (PP) is a recyclable thermoplastic, potential as a matrix in composite particle boards. Specimen testing includes tensile tests and macro-microstructural analysis. The highest tensile strength, 23.642 MPa, was found in 100% HDPE composition. A blend of 60% HDPE, 30% PP, and 10% cassava pulp reached 16.026 MPa. In contrast, the lowest strength, 4.420 MPa, was in 60% PP, 35% HDPE, and 5% cassava pulp. Increasing HDPE boosts material strength due to its strong and flexible mechanical properties, but too much cassava pulp weakens it. Macro analysis showed air cavities in the specimen's center, while micro analysis revealed HDPE and PP did not mix homogeneously, with cassava pulp more mixed in PP.

Development of Rooftop Solar Power Plant (PLTS) on Parking Areas for EV Charging Station at Sumsel-8 Mine Mouth Power Plant

2025-05-05T07:40:26+00:00

The PLTU MT Sumsel-8, a coal-based power plant, has significant potential to implement renewable energy solutions to enhance energy efficiency and operational sustainability. One viable solution is the construction of a rooftop solar power plant (PLTS) in the parking area with an off-grid system. This system is designed with a capacity of 162 kWp to meet the electricity needs of supporting facilities at the power plant, such as lighting, cooling systems, and office operations. In addition to generating clean energy, the installation of solar panels on the parking lot roof also provides additional benefits, including vehicle protection from solar heat and the optimization of previously underutilized land. However, before implementing this system, a comprehensive feasibility study is required, encompassing technical, economic, and environmental evaluations. Simulation results using Helioscope software indicate that the proposed PLTS system with the stated capacity can generate 225.413,2 kWh of energy per year. Considering the energy storage capacity of electric vehicles, the simulation results suggest that the energy production can provide enough charging capacity for 7 to 8 vehicles per day for vehicles with battery capacity 77 to 82,5 kWh and up to 23 vehicles per day for smaller capacity battery which is 26,7 kWh. This study is expected to offer recommendations for the implementation of rooftop PLTS at PLTU and contribute to the strategy for sustainable energy options in Indonesia.