Jurnal Teknik Mesin
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Low-frequency Stick-slip of A Creep Groan on A Simple Caliper-slider Experimental Model
Get PDFThis paper discussed a preliminary study of low-frequency stick-slip of a creep groan using a simple caliper-slider model. The experiment model is constructed based on the real operating system behind a vehicle braking system. The model consists of a sliding bar, a caliper and an arm. The analysis shows that the main frequency of generated low-frequency stick slip of the creep groan is 100 Hz with sound pressure level of 70 dB. It is found that the low-frequency stick-slip motion the result of the vibration in tangential direction. The frequency of the generated stick-slip is close to the bending natural frequency of the system. Several parameters that are important in the generation of the low-frequency of stick slip are the sliding velocity and the contact roughness. Therefore, further study of creep groan should take into account these important parameters as well as other operating parameters
FEM Simulation of Polycarbonate Alloys-made Sheet under a Drop Weight Impact Test: Deformation and Failure Performances
Get PDFThis paper presents a study of deformation and failure performances of a plastic sheet made of polymer alloys subjected to drop weight impact of a cylindrical mass with hemispherical tip at a certain velocity by using dynamic explicit finite element code of MSC. Dytran. An available material model in the finite element system, called piecewise linear plasticity, was applied in the simulation for describing the large strain, non-linear behavior of the polymeric materials. Maximum plastic strain failure criterion was used to simulate the impact failure. In the simulation, the mass served as a rigid surface strikes perpendicularly the potential impact region of an arbitrary designed- plastic sheet that was considered in the form of a fully-clamped circular thin plate. Contact between the mass and plate was applied and friction coefficient m between the mass and plate was assumed to be a constant value of 0.3. In order to study effect of the assumed friction coefficient value, additional simulations of the impact test have been performed using m = 0. Some limitations in the use of the material model were illustrated through the analysis of results from two types of tough polycarbonate (PC) alloys: PC/ABS and PC/PBT blends. Impact force-displacement relationships of each alloy were then compared to the test result
Kaji Optimasi Desain Cetakan Injeksi Moulding pada Unit Pengolahan Limbah Plastik Dinas Kebersihan dan Pertamanan Kota Banda Aceh
No full textHigh impact of product damage by injection molds process on polymer waste processing unit was seriously affected to quality and sustainability production. In this study effect of injection mold design was minimized by investigated and redesign injection molding system. The main equipments of injection molding system which is available at Unit Pengolahan Limbah Plastik Dinas Kebersihan dan Permanan Kota Banda Aceh are polymer waste cutting, splitting and cleaning devices and injection molding machine. According to observation conducted previously on current injection molding product and mold found that failure of product caused by mis-design of mould. Products defects occurred are sink mark, weld line and air trap. Mold-Flow software was used to modeling and simulating injection mold process. Based on simulation result and discussion found that defected products have been able minimized. By modifying sprue location and redesign mold, products defect minimized and injection pressure still remain to push polymer to mold inlet at range 0,72-0,48 Mp
Rekayasa Komposit Serat Sabut Kelapa sebagai penguat dan Styrofoam Sebagai Matriks
Get PDFCoconut fibre which is extracted from outer shell of a coconut is a type of natural fibre used as composite board reinforcement in this research. The fibrebinder used in this research was stryrofoam which is a material from polysterene. This research was aimed at finding out the appropriate composition by weight between coconut fibre and polysterene and to find out the physical, mechanical and morphological characteristics of composite board resulted from the engineering process. The construction of composite board was started by cutting the fibres with the length of 5 mm, then dyeing them into NaOH for 4 hours. After those process, the fibres were dried and weighted. The Styrofoam was dissolved into silane before it was weighted based on its composition. After the coconut fibre and polysterene mixtures were mixed,they were poured into the composite board mold. The benefit of this composite board is that it is more water resistant. The test results for tensile, density, moisture content, and thickness swelling meet the Indonesian National Standard (SNI) 03-2105-2006. The flexural strength of composite board which meets the standard is the compositions of 30:70, 40:60, and 50:50, while the compositions of 60:60 and 70:30 do not meet the standard
Evaluasi Pembangkit Listrik Tenaga Angin Kecepatan Rendah Sebagai Penggerak Refrigerator Es 300 Kg/Hari Untuk Nelayan
Get PDFGenerally, the fishermen in the fishing village of Lancang only 20 trips/month of the year. The average total amount of ice required for the first type of fishing boat is 300 kg ice/day and 150 kg of ice/day for both types of fishing vessels. So, based on the total number of observations of ice demand data is 9000 kg/month (300 kg ice/day). One solution that can be taken is the utilization of wind energy resources owned by the village to generate electrical energy as the driving engine refrigerator. Methods of research conducted in three phases, the first stage is filled with wind potential measurement, processing and analysis of wind speed data. In the second stage of the development of modeling performed to evaluate the performance of Genesis turbines based on the data load and wind potential. The third stage is filled with measurements of 10 KW wind turbine performance and then made comparisons with modeling results. From the analysis of wind speed data obtained from the measurement results obtained by the average wind speed reaches the village of Lancang 3-5 m/s at a height of 15 m above sea level. Based on analytical results obtained using the software Homer wind turbine energy production is 7.474 kWh/year and the results of measurements of overall performance of the turbine can be concluded that wind turbines are the object of study is only able to deliver an average power 3-7 KW
Karakterisasi Material Penyimpan Kalor Laten Menggunakan Metode T-History
Get PDFThe capacity of energy storage and temperature storage has come into consideration in choosing thermal energy storage system. Absorbed or released material either big or small can be determined by finding the value of the specific heat (Cp) and the latent heat fusion (HL). Available method to determine latent heat of fusion (H), specific heat (Cp), temperature melting (Tm) and thermal conductivity (k) are conventional calorimetry method, Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). Measurement of physical properties of phase change material using DTA and DSC has disadvantage due to small weight that used for sample (1-10 mg), so that thermophysic of sample usually different when the material is used in large quantities. In this study, T-history method is used to determine thermophysic heat storage material. Examination results show the match value in latent heat (Hm) of paraffin with DSC testing results are 249.42 KJ / kg with 251 KJ / kg. The results of calculations using the T-History for paraffin obtained at temperature Tm 52.72 to 59.9 0C; Cp of 2.54 to 3.57 KJ / Kg.K; Hm at 249.42 KJ / Kg; k of 0, 18 W / mK. For bee-wax Tm obtained at temperatures from 52.4 to 61.79 0C; Cp of 2.65 to 3.45 KJ / Kg.K; Hm of 171 KJ / Kg; k of 0.234 W / mK. For fat cow obtained at temperature Tm 40.82 to 44.10C; Cp of 3.19 to 4.16 KJ / Kg.K; Hm at 60.13 KJ / Kg; k of 0.181 W / mK. It can be concluded after examanination that Paraffin is a good material as a phase change material (PCM) in comparison to bee-wax and beef fat
Optimasi Penyerapan Panas Memanfaatkan Energi Matahari pada Kolektor
Get PDFSolar energy is a renewable energy that can be utilized for human needs for various purposes such as electricity, heating, hair, and so forth. Solar collector is a device that collects solar energy and converts it into thermal energy and redirects the energy back into the fluid. Three variations of barrier angle were prepared in order to optimize the absorption of solar energy in a collector. Multiple pass turn were utilized to maximize the heat absorption. The size of the collector is 250 cm 85 cm. Each side of absober box is coated with aluminum of 10 mm thick. Iron sand is used as absorber with thickness of 6 m. The collector box is tilted with 15 angle. Measurements were carried out for each multiple pass turn angle ; 130, 180 and 90. The tests were carried out in an open field in front of the Faculty of Engineering, Syiah Kuala University. The results show that temperature tends to be similar for all three variations of barrier angle. For the barrier angle of 130, the highest temperature achieved was 93.3C during 12:00 to 13:00 pm. The highest temperature achieved for the other two variations are 91.2C for the barrier angle of 90 and 90.2C for the barrier angle of 180
Pengaruh Komposisi Paduan Al-Si Terhadap Kerentanan Hot Tearing
Get PDFHot tearing and hot cracking is a metal alloy casting product defects caused by several factors such as alloy composition, casting temperature, mold temperature, mold shape and even casting system itself. The study has been developed to find the phenomenon of the hot tearing by varying the alloy composition, techniques and methods. Increasing Si alloy composition can improve hot-tear, mold modification CRCM (constrained Rod Casting Modified) Horizontal method can be used to analyze the hot tearing. The material used is aluminum with Si composition is 0.24pwt as base and material ADC12 as additive with Si composition is 10.56pwt to increase Si composition. Hot-tearing sensitibility value obtained by using the equation then showing into the chart HTS footprint. HTS values for Si alloy with a composition of 0.24pwt is 12 and the HTS value for alloys with compositions 1.05pwt Si is 18. Cracks formed in the product starting with the smooth (hairline cracks) category to the complete (specimen broken) category. The higher Si content can increase the cracked in product castings, so that the higher Si composition more tendency to tear
Modeling of Underground Heat Exchanger for Heat Pump and Air Conditioning Systems
Get PDFAir conditioning and heat pump systems can use the ground as a medium to dump or absorb heat energy to increase efficiencies. As compared to the air, the ground has lower temperature in the summer and higher in the winter. In this research, the vertical U tube underground heat exchanger that can be used to harvest geothermal energy, has been modeled by using two dimensional finite difference methods. The model is not only able to estimate the water temperatures out of vertical U tube underground heat exchanger, but also capable of calculating the temperature profile change of surrounding soil under various water entering heat exchanger and weather conditions. The heat transfer process between the underground heat exchanger and soil has been investigated and profiles of soil and water temperatures are presented
Pengembangan Algoritma untuk Menganalisis Frekuensi Pribadi Poros dengan Rotor Ganda
Get PDFVibration analysis is very essential to be considered in designing a rotor shaft. By the development of computer technology, the vibration analysis of the rotor shaft can be easily performed by numeric method. The objective of this research is to develop an algorithm to determine the natural frequency of a rotor shaft of a dual rotor system. The equation of motion of the system is derived from the kinetic and potential energy. By applying Lagranges equation and converting them into matrix form, the equations can be easily solved numerically. Through this approximation is developed computer program. The model is a rotor system built of a rotor shaft and two disks. The rotor shaft is numerically divided into several line elements. From the global matrices of the elements, it is resolved the eigen values of the system which are then converted into the natural frequencies. The validation of the program result with analytical calculation shows a very close result