The fishing ship propulsion system will affect the performance of the ship and impact the fishermen’s income. A crucial factor is the level of efficiency produced by propellers mounted on fishing vessels. In B-series propellers, propeller efficiency can be optimized by varying the size of the geometric dimensions. This propeller optimization process can be done after the ship resistance value is known. In Cirebon waters, as in other regions in Indonesia, the selection of propellers by fishermen is still unclear. Most are only based on the availability of goods on the market, without looking at how big the actual ship resistance occurs. In this research, one of the fishing boats that will be built will be chosen to estimate the ships’ resistance. After that, by considering the engine used as its driving source, the geometry dimensions that can produce the highest efficiency are sought. Estimation of ship resistance is sought by the Holtrop method, and propeller optimization is carried out with the help of software. From the results of this study, the value of ship resistance commonly used by Cirebon waters fishermen is 2.608 kN at an operational speed of 7 knots. Optimized propeller design provides a 6 percent increase in efficiency compared to previously used propellers.
The government of Indonesia has a regulation called local content to push the manufacturing industries in order to increase their competitiveness. In order to reach that goal, technology transfer has been done, but it is a long way to go and impractical. So, one way to go is by the understanding of the product that has to be made. Reverse engineering is a specific technique to use because of its practicality. As the name implied, reverse engineering is the inverse of engineering design because the starting point is the product itself instead of the idea. In this paper, the product used as a case is the body of the fire-safe valve. The final goal of the reverse of the body part of the valve is the idea behind it or called the design intent. However, it is going to be a long process, and as the first step that will be presented in this paper, the goal is to get its CAD model of the fire-safe valve body.
Published paper on modelling of propeller turbine blade and runner is not commonly found, especially those using Autodesk Inventor. One of them is titled CAD Modelling of Axial Turbine Blade using Autodesk Inventor. However, the road taken is quite complicated and should be repeated from the beginning whenever new geometrical characteristics of a new axial propeller turbine will be modelled. Currently, Autodesk Inventor has introduced the new tool that help sketching the spline lines either in 2D plane or 3D space simplifying the task of 3D modelling of propeller turbine blade, called Equation Curve. The Equation Curve tool requires the codes for creating the spline lines. To create the codes, two sources have been used: NACA report no. 460 and modelling methodology proposed by Milos in his paper. In NACA report no. 460, it is explained that NACA 4 Digit Series is created by combining mean line with the thickness variation curve of Gottingen 398 and Clark Y. This airfoil has 4 different lines with their own equation. The equations can be used for sketching in 2D plane. However, the solid model of the runner blade is formed from the airfoils in cylindrical surface. Then, as explained by Milos in his paper, the procedure is as follows: sketch the airfoil in 2D plane that is the tangent of cylindrical surface, move the airfoil to its center, rotate to its stagger angle, and project it to cylindrical surface. The result of this process will be the equations of lines in 3D space. Transform them to the Inventor codes. Input these codes to 3D Equation Curve tool to create the 4 lines for each cylindrical surface section of blade. Making the solid model of runner the following step is required: use loft command to create blade surfaces, use the stitch command to solidify, use the pattern command to create other blades, create hub, and lastly combine blades and hub. The solid model of the runner then is tested by simulating it using ANSYS Fluent. The hydraulic efficiency of the model is 85%.
Dies merupakan salah satu peralatan dalam dunia manufaktur yang dipilih karena kecepatannya dalam menghasilkan produk seragam dengan kapasitas produksi sangat besar. Salah satu industri pengguna dies yang paling banyak adalah manufaktur otomotif pada bagian bodi (karoseri). Perkembangan industri jenis ini berkembang sangat pesat di Indonesia dan menopang pereknomian. Bagian bodi dari produk otomotif terdiri dari beberapa bagian. Salah satu bagian bodi ini bernama fender. Fender merupakan bagian bodi yang melingkupi komponen roda. Pada makalah ini, objek dari penelitian adalah pemilihan pegas sebagai langkah pada proses perancangan dies pembentuk fender truk. Pegas ini berfungsi untuk menjamin besar gaya yang harus diberikan agar pelat yang dipotong dapat menghasilkan fender yang sesuai. Gaya rata-rata yang dibutuhkan adalah 216,84 kgf. Kajian akan dilakukan dengan menggunakan pendekatan teoritik yang kemudian dimasukkan ke dalam perangkat lunak. Kajian ini memberikan alternatif cara pemilihan pegas pada komponen dies. Berdasarkan hasil kajian maka dipilih pegas berjenis SWM. Spesifikasi pegas sebagai berikut: diameter 40 mm, panjang 45 mm dengan konstanta pegas 22,2 kgf/mm. Jumlah pegas yang diperlukan adalah 6.
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