Studi Karakteristik Stabilitas dan Konstruksi Kapal Berbahan High Density Polyethylene (HDPE)

The development of fishing and marine tourism requires the support of naval architecture, especially in small boat. The use of wood as the main material for shipbuilding has recently become a problem considering the decreasing availability of wood, while the use of fiber is classified as less environmentally friendly because it uses chemical resin and difficult to repair when it breaks and cannot be recycled. The aim of this research is to design the High-Density Polyethylene (HDPE) boat. The design was carried out by using naval architect design software. The stability of boat was calculated by using three loading conditions such as when leaving the port, in the sea and when returning to the port. The International Maritime Organization (IMO) safety criteria was using to evaluation of boat stability where the three loading conditions have met the IMO standard. The construction of HDPE boat was carried out by using DNV rules.

Pengembangan Alat Bantu Arbor untuk Pembuatan Roda Gigi pada Mesin Frais Vertikal

The machining process is included in the classification of metal cutting processes, which are used to change the shape of metal or non-metallic product by cutting, peeling or separating. One of the machines used in this cutting process is a vertical type milling machine. This machine functions to make a product, one of which was a gear. The supporting equipment needed to make this gear was a vertical arbor tool. The material used in the manufacture of this product was a cast carbon steel type using the design method for manufacturing and assembly (DFMA), which began by examining and identifying needs, conceptualizing and designing products and making these products tailored to the dimensional specifications of standard and common cutter modules in the market. The results of the manufacture of this tool were directly tested for the manufacture of gears of various sizes and produced products whose deviations were within the tolerance of the measuring instrument, namely in the range 0 to 2%. In addition, the von Mises stress simulation at an engine speed of 150 Rpm, 450 Rpm and 750 Rpm and the resulting maximum stress was still below the yield limit, so it was safe to use.

The Influence of Different Slicer Software on 3d Printing Products Accuracy and Surface Roughness

Rapid Prototyping (RP) is a manufacturing process that produces a 3D model CAD to be a real product rapidly by using additive manufacturing technology. In this case, the product will print layer by layer uses a 3D printer machine. The 3D printer requires slicer software to convert CAD data into data that a 3D printer machine can read. Research is done to analyze the effect of three kinds of slicer software on 3D printing objects on the accuracy and surface roughness of the product. The 3D model CAD is sliced using three different slicer software, namely Ideamaker, Repetier Host, and Cura. The slice model result from each slicer will be printed on a 3D printer machine with the same process parameters to be compared. Then the product's dimensional and surface roughness will be measured to determine the effect of each slicer on product quality. The best quality of the product reflected the most suitable slicer software for the 3D printing machine that used. The best results achieved by Cura slicer because it has resulted in small dimensional deviations (max 0,0308±0,0079) and stabile high surface roughness of the product (max 1,585+059).

Analisis Ketidaksesumbuan Poros (Misalignment) pada Rotordinamik Berdasarkan Sinyal Suara

This research aims to identify misalignment of the rotor dynamics based on sound spectrum characteristic. In this study, rotor dynamics consist of motor, shaft, coupling and bearings. Three types of misalignment were considered, namely parallel, angular, and combination misalignment. In order to obtain the best signal, microphones were used as sensors to capture sound signal placed on coupling and each bearing. The signal obtained was in time series. The sound signal in the time domain is then filtered to remove noise signals, which are then transferred to be signals in the frequency domain using Fast Fourier Transform (FFT). From the test results, it is found that in the case of parallel misalignment, the sound frequency spectrum is obtained with a peak amplitude at 2x rpm. The case of angular misalignment obtained a sound spectrum with a peak amplitude value and is dominant at 1x rpm than 2x rpm. Meanwhile, in the case of a combination of parallel and angular misalignment, a peak amplitude sound spectrum appears at 1x rpm and 2x rpm with relatively close spacing between the peaks of the sound spectrum. The result shows that sound signal can be used for identification of misalignment of the rotor dynamics.

Analisis Variasi Arus Pengelasan Kombinasi SMAW-FCAW dengan Kampuh Double V-Groove terhadap Kekerasan dan Struktur Mikro Dissimilar Material JIS G3101-SS400 dan ASTM A36

This study aims to determine the effect of variations of the current with combining two welding techniques SMAW and FCAW in double v-groove against the hardness and microstructure of the dissimilar material of JIS G3101-SS400 and ASTM A36. JIS G3101 SS400 and ASTM A36 each with a thickness of 10 mm were used as the materials. The combination of SMAW welding with E7018 electrodes and FCAW with E71T-1 were used as the welding techniques. The current used in SMAW welding were 60 A, 75 A, and 90 A. While in FCAW welding the current used were 190 A, 205 A, and 220 A. Hardness and microstructure tests were carried out on each sample. The results of the study showed that the current in welding process affect the hardness value and microstructure of material. The higher the welding current, the value of hardness of the material going to decrease and vice versa. The highest hardness values in SMAW and FCAW welding are at currents of 60 A and 190 A. Then the current in the welding process also affect the microstructure produced in the weld and HAZ. The formed microstructure containing pearlite and ferrite. The higher welding current, the percentage of pearlite produced increase and the percentage of ferrite decrease.

Pengaruh Campuran Bahan Bakar Biodiesel WCO - Diesel terhadap Karakteristik Api Hasil Pembakaran Spray Difusi pada Concentric Jet Burner

Biofuels from waste cooking oil (WCO) represent a sizable opportunity not only in terms of energy production but also as a way for sustainable development despite their low yield, higher viscosity, lengthy production time and cost. Alternatively, biodiesel can be blended at an appropriate blending ratio with convention diesel oils. The biodiesel and its blends is proved to give better emission characteristics than conventional diesel oils. This study aims to experimentally investigate the effect of the fuel blend on the combustion characteristics of WCO biodiesel. The characteristic are the droplet size, flame height, flame width and temperature distribution. In this study, the blended fuel are B0 (Solar), B10, B20, B30, B40 and B100 (WCO biodiesel). Measurement and visualization of the combustion flame for each variation of the fuel mixture was were tested at different pressures, namely 4 bar and 5 bar. The experimental results show that the droplet size increases with increasing WCO concentration in the fuel; on the other hand, visualization and calculations show that the height and width of the flame of the fuel mixture decreases Observation on the temperature distribution shows that the WCO biodiesel mixture has the potential to increase the fire temperature at certain points

Pengaruh Double Chamfer terhadap Distribusi Suhu dan Daerah Zpl pada Sambungan Las Gesek AL6061 dengan Simulasi Komputer

Welding is one of the metal joining processes in manufacturing. CDFW (continuous drive friction welding) is a welding process to join two workpieces by applying pressure at one end of the object and rotating another one where the friction action applies at interface. The purpose of this study is to study temperature distribution on the surface of the welding area and the heat-affected zone represented by a fully plasticized zone (Zpl) and to get an insight of a friction welding process. The variables of CDFW used were double chamfer angle, upset pressure, and burn off length. The initial area of friction was equal that is at a diameter of 14 mm. The method of modeling the CDFW friction welding is via computer simulations using ANSYS 18.1 software. This research uses aluminum material type Al6061. The Taguchi method was applied in designing the simulations. In this modeling, the model with the double chamfer of 15 °, the upset pressure of 120 MPa, and the burn-off length of 9 mm has a small ZPl area of 10.256 mm2. Whilst the specimen model, with a double chamfer angle of 45 °, the upset pressure of 240 MPa, and the burn-off length of 7 mm has a large Zpl area of 56.55mm2. The area of a narrow fully plasticized area caused by small chamfer angle and an upset pressure of 240 MPa. The area of fully plasticized zone shows how much material can be integrated during the friction welding process and how much strength of the weld metal. The model with the chamfer angle of 15 º, the upset pressure of 240 MPa, and the burn-off length of 9 mm has the widest temperature distribution and the highest maximum temperature. Meanwhile, the model with the chamfer angle of 30º, the upset pressure of 120 MPa, and the burn-off length of 9 mm has the narrowest temperature distribution and the lowest maximum temperature. The smaller chamfer angle increased upset pressure and burn-off length result in the wider temperature distribution, higher maximum temperature, and smaller Zpl.

Pengaruh Sintering Serbuk Batuan Basalt sebagai Bahan Penguat pada Komposit Polyester terhadap Sifat Fisik dan Mekanik

Basalt rock has great potential in Lampung Province but is only used as a building construction material. Basalt has superior characteristics such as abrasion/wear resistance, compressive strength and chemical reaction resistance making it suitable as a filler or reinforcement for composites. This study aims to determine the effect of basalt rock powder sintering as a reinforcing filler on the mechanical and physical properties of polymer matrix composites. The parameters used included variations in sintering temperature: 8500C, 9500C, and 1.0500C, variations in particle size: 100 < X < 150 mesh, 150 < Y < 200 mesh and 200 < Z < 270 mesh, and the volume fraction comparison of basalt sintering powder and polyester resin. 70: 30%, 80: 20%, and 90: 10%. The experimental design uses the L9 3^3 taguchi orthogonal array run 9 specimens. Taguchi analysis shows that the parameters that affect the mechanical and physical properties are the sintering temperature. sintering temperature contributed 61.77% to wear, and 87.58% to compressive strength, and 95.32% to composite density. The experimental results with the best value obtained a wear value of 0.235 x 10-7mm2 / kg, a compressive strength of 118.873 MPa, and a density of 2.272 gr/cm3.

Quality Function Deployment (QFD) and TRIZ in Briquette Cookstove Design and Simulation

Poor cookstove design can harm the user's health and environment. This research aims to obtain an efficient cookstove design, environmentally friendly and operated easily. The cookstove design process using a combination of QFD and TRIZ. QFD able to capture customer needs through a questionnaire and interview. The data collected then processed to build a House of Quality (HoQ), one of the tools in QFD. QFD results in the design parameter of the briquette cookstove, which is incorporated in the concept design. The TRIZ method is utilized to understand the problem that might occur in the concept design and focus on solving the root causes. The next step is a detailed design where the dimensions, combustion chamber capacity, and supporting features are explained. The combination of QFD and TRIZ result in a briquette cookstove concept design which is easy to clean and operate. The combustion system is Top-lit Up-Draft (TLUD). The burning chamber has two air inlets, namely primary and secondary. The primary air inlet supplies the air from the bottom of the burning chamber, partially burns the briquette, and produces flue gas. The secondary air inlet is in the shape of an oval to supply air in the burning chamber's upper part to burn the flue gas completely. A complete combustion process will increase combustion efficiency and reduce emissions. A computational simulation shows the velocity distribution inside the burning chamber.

Karakteristik Aerodinamika Pontoon Pesawat NXXX Versi Amfibi

Seaplanes are aircraft that can take off and landing on water. A seaplane’s requirement is its need to take off and landing on watery conditions which is equipped with a pontoon. Pontoon of a seaplane needs to be evaluated in terms of aerodynamics characteristics when a seaplane flies. The purpose of this study is to determine the correlation of various geometric combinations of deadrise angle, step height, and constant cross-section length with the values of coefficient of drag (CD), coefficient of lift (CL) and coefficient of moment (CM). The methodology was carried out by simulating Computational Fluid Dynamics (CFD) using OpenFOAM software. The results of this study could be concluded that deadrise angle affected coefficient of drag (CD), coefficient of lift (CL) and coefficient of moment (CM) with each value of 0.0055, 0.0044, -0.0036, while step height didn’t influence significantly on coefficient of drag (CD) and didn’t affect coefficient of lift (CL) and coefficient of moment (CM). Constant cross-section length didn’t affect significantly on coefficient of drag (CD) and coefficient of lift (CL) but increasing constant cross-section length increased coefficient of moment (CM) with a value of -0.0039.