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This article focuses on the production of tensile test (ASTM D638-03) specimens using fused deposition modelling technique as preliminary study for preparation of 3D-printed SUAV wings. Carbon-PLA (nylon 6/66 copolymer adding with 20% of carbon fiber) was used as 3D filament. There were 7 printing orientations: 0o, 15o, 30o, 45o, 60o, 75o, and 90o based on tensile axis with 3 specimens for each direction (21 specimens in total). Printing parameters were set using open-source slicing application CURA. It was found delamination and fracture outside the gauge length causing high deviation of the mechanical properties value. So, the result of the testing test seems like do not comply with theoretical aspect of relationship between fiber orientation and tensile properties of composite materials. Taking care of printing parameters and increasing the number of specimens has an opportunity to achieve high precision results since precise data is crucial as a starting point for the development of SUAV wings.

Gray cast iron has graphite flakes which makes it relatively weak and brittle. The addition of magnesium to gray cast iron resulted in nodular cast iron which has spherical graphite. The aim of this research was to investigate the changes in the microstructure and strength due to the addition of magnesium to gray cast iron. Microstructure observations were made by metallographic testing using Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Tensile testing was carried out to measure the yield strength, tensile strength, and modulus of elasticity. The addition of magnesium to gray cast iron was observed to increase the yield strength by 179%, tensile strength by 238%, and decrease the modulus of elasticity by 94%.

The research objective is to investigate the formation of new compounds and the mechanical properties of Double Side Friction Stir Welding (DS-FSW) welding with Cu particle reinforcement. Aluminum alloys of AA6061 and 12 μm Cu powder were chosen as the main materials. The addition of Cu particles is conducted in single groove and double groove. The DS-FSW process uses CNC milling with a feed rate of 80 mm/minute and 1000 rpm of tool rotation. Observation of the microstructure was carried out by using optical metallography, and X-ray diffraction. Microhardness testing was done to determine the mechanical properties of the material. The results showed that the increase in the hardness value of 23.39% occurred in the double groove material. MMCs detected were Al2Cu, and AlCu2Mn.

Using the nanoindentation technique, the creep deformation behavior of Zr55Co25Al15Ni5 bulk metallic glass (BMG) in the range of 0.94–1.03 glass transition temperature (Tg) and different loading rates was studied. The Maxwell–Voigt model was applied to describe the deformation and relaxation kinetics of BMGs near the glass transition. According to the results, the serrated behavior of deformation, as the indicator of shear events, disappeared at higher loading rates and temperatures. This event was due to the high rate of defect formation and propagation at higher temperatures under the indenting process. Based on the Maxwell model, it was found that the creep deformation can be divided into two distinct characteristic relaxation times in the range of 0.1–0.68 S and 8.3–24.8 S, respectively. At the higher temperatures, the creep deformation tends to have higher relaxation times, which corresponds to the viscoplastic behavior of material.

Nodular cast iron is a type of cast iron with spheroid graphite surrounded by ferrite matrix and / or pearlite. The size of the graphite and its matrix affects the mechanical properties of the cast iron. This research was conducted to investigate the effect of Magnesium composition on strength, stiffness and toughness of nodular cast iron. Magnesium addition is performed by adding FeSiMg alloys. After that, the composition of magnesium was investigated by using spectrometry. Then tensile test was conducted to obtain the yield strength, tensile strength and modulus of elasticity. Further, impact test was performed to determine the impact energy needed to break the material. The result showed an increase of yield strength, tensile strength and stiffness and a decrease of toughness.

Sand casting is one of manufacturing process that still exist today. Numerous products are produced to serve industrial and domestic use. Defect could lead to product performance, and unfortunately inevitable in a casting process. This paper aim to investigate typical defect resulted from sand casting process. An aluminum cooling fan was selected as the model since it has complicated shape with different thicknesses. The casted fan was investigated under photo micro for defect analysis. Porosity, gas inclusion, pinhole, and shrinkage were found as the common defects occured at different part of the fan.

The objectives of the study is to investigate the formation of intermetallic compound and the mechanical properties of the underwater welding. AISI 4012 steel was selected as the material and two types of electrode E6013 and E7018. The variations of electric current used in this study were 80,100, and 120 amperes. The underwater welding was conducted in plain water pool and 3 meters depth by using SMAW. Tensile test and SEM-EDS were carried out to investigate the tensile strength and appearence the intermetallic layer.The results of this study indicated that the highest value of tensile stresswas found on the use E7018 electrodes and 80 amperes electric current. While the lowest value was found in the use E6013 electrodes with 120 amperes. Intermetallic layer was detected base on the SEM-EDS investigation.

Fresh vegetables and fruits need oxygen (O2) to carry out their metabolic activities, particularly respiration. The procedure where the actively respiring commodity is sealed in film packages made of polymer to change the CO2 and O2 levels of concentration inside the package environment required to increase shelf-life and preserve freshness is referred to as modified atmosphere packaging (MAP). To affect the product's metabolism being packaged or the activity of organisms that cause degradation to extend the time of preservation, it is frequently desired to create an environment high in CO2 and low in O2. MAP changes the environment and increases moisture preservation that has a bigger impact on quality preservation. Moreover, packing separates the product from the surrounding environment, assisting in the creation of circumstances that, if not hygienic, at the very least minimize exposure to infections and pollutants, as well as physiological damage. MAP is a dynamic mechanism that occurs concurrently throughout permeation and respiration. As a result, MAP design necessitates the assessment of the product's intrinsic features, such as film permeability, optimal O2 and CO2 gas concentrations, and respiration rate. The goal of MAP design is to specify parameters that will provide the greatest feasible environment within the package for increasing the product's shelf-life in the quickest possible time. This is accomplished by synchronizing the packed produce's respiration rate with O2 and CO2 gas penetration rate through the film. The current study contains a detailed discussion of all of these elements of MAP.

Arang daun bambu tutul sebagai kajian produk nanopartikel dan penghasil silica yang memiliki berbagai keunggulan dari segi sifat fisika dan kimia. Pada penelitian ini produksi nanopartikel menggunakan High Energy Milling (HEM) tipeshaker mill untuk memproduksi nanopartikel dari arang daun bambu tutul. Pada penelitian ini dilakukan uji PSA untuk menganalisa ukuran partikel, untuk menganalisa distribusi morfologi partikel dan komposisi kimia yang terkandung dalam material menggunakan uji SEM dan EDX. Siklus yang digunakan pada penelitian adalah 2 juta siklus dengan putaran motor listrik 1000 rpm, dan diameter bola baja 1/4 inchi. Tabung stainless steel berjumlah 4 dengan diameter tabung 2 inchi dan tinggi tabung 120 mm dengan perbandingan volume ruang kosong tabung yaitu 1:1, 1:2, 1:3, dan 1:4 dengan material. Penelitian ini bertujuan untuk mengetahui pengaruh volume ruang kosong tabung dan rata – rata diameter partikel, distribusi partikel, dan komposisi yang terkandung dalam partikel hasil tumbukan dengan alat shaker mill. Hasil penelitian ini menunjukkan bahwa volume ruang kosong tabung sangat berpengaruh pada mekanisme tumbukan. Dari uji PSA semakin besar volume ruang kosong tabung, semakin kecil ukuran partikel material yang dihasilkan. Hasil uji SEM dan EDX didapatkan unsur kimia karbon yang paling tinggi 68,47 % pada volume 1:1 ruang kosong tabung. Sehingga arang daun bambu tutul merupakan sumber potensi sebagai penghasil silica.

Garbage is a serious problem if it is not managed properly, both organic and non-organic. Inorganic waste, for example, plastic, metal, glass, and charcoal from coal combustion are difficult to decompose in the soil. HDPE (high-density polyethylene) plastic is one type of inorganic waste that is difficult to decompose, but this plastic can be recycled. The objective of the study is to develop light cement blocks by using the waste of HDPE, coal bottom ash and cement. The research guide was referred to SNI (Indonesian National Standard). The SNI-03-6825-2002 is for testing of the compressive strength and SNI 03-0349-1989 for the testing of the water absorption. The size of the specimen was 5 x 5 x 5 cm. In this study, the compositions of HDPE: coal bottom ash were varied by 70%: 0%, 60%: 10%, 50%: 20%, and 40%: 30%. The Holcim cement was 30% of the volume fraction. Testing was conducted after the specimens stay in 7 and 28 days. For the 7 days old of specimens, the highest compressive strength has resulted from 50%:20% composition with the value of 5.88 N/mm2. For the 28 days old specimens, the highest compressive strength was 8.34 N/mm2. The lowest water absorption test was delivered by the more coal bottom ash in the composition of 40%:30%. It was 16.971%. The more coal bottom ash, the less water absorption. The mean of specimens density was 1.076 gr/cm3. The result of the research shows that recycles HDPE and coal bottom ash as concrete block meet the required strength.

The Abaqus software was used to simulate the creep behavior of a cylindrical tube of Sanicro-25 austenitic steel under an internal pressure of 11.3 MPa at a uniform temperature at 750 °C. The data used for the simulation input were obtained from the experimental data of a previous work. The hidden information of material parameters was estimated from the shape of creep strain versus time plots obtained from the experimental data. The validated results between the simulation and the experimental data produced the material parameter of the creep power law which were set at 2.6 x 10-22 for the power law constant and 9 for the stress exponent. The parameters were further used to explore the stress and strain inside and outside of the tube wall and the thickness changes of the tube wall.

The purpose of this research is to investigate the corrosion resistance of 5052 aluminum alloy to increasing salinity in sea water. Salt spray chamber was used to measure and compare the corrosion rate of 5052 aluminum alloy with weight reduction method. The experiment was conducted by varying the three concentrations of NaCl solution to compare the corrosion rate of the metal. The test specimens used were aluminum alloy 5052 with length of 6 cm, width of 4 cm and thickness of 0.7 cm. The tests were carried out for 48 hours, aggressive NaCl solutions with concentrations of 3.5%, 4% and 5% were used as an artificial sea water corrosion medium and the temperature in the test chamber was maintained at 35 °C. Corrosion rate for 3.5% NaCl solution, 4% NaCl solution and 5% NaCl solution were 0.197 mm/year, 0.541 mm/year and 0.558 mm/year, respectively. The higher concentration leads to greater corrosion rate.

Pengurangan berat bahan pada komponen kendaraan merupakan salah satu isu yang ada di dunia industri otomotif. Suspensi pegas daun merupakan salah satu item potensial untuk menurunkan berat kendaraan karena menyumbang 10% - 20% dari berat unsprung weight. Tujuan penelitian ini adalah untuk melakukan optimisasi desain pegas daun dan analisa statik pegas daun pada kendaraan roda 3. Optimisasi desain dilakukan dengan Design of Experiment (DOE) pada pegas daun Original dengan tiga variasi desain masing-masing yaitu modifikasi 1, modifikasi 2 dan modifikasi 3. Modifikasi 1 dilakukan dengan pengubahan desain tanpa menggunakan alur/slot, Modifikasi 2 dilakukan dengan pengubahan desain dengan menggunakan 3 alur/slot , dan Modifikasi 3 dilakukan dengan pengubahan desain dengan menggunakan 1 alur/slot. Metode penelitian ini dilakukan dengan menggunakan konsep reverse engineering yang diawali dengan mengumpulkan data-data geometri pegas daun pada kendaraan roda 3. Data-data tersebut dipakai sebagai acuan dalam mendesain komponen mengunakan software CATIA V5. Assembly komponen menjadi kesatuan dilakukan setelah semua bagian sistem pegas daun selesai digambar. Setelah gambar desain dihasilkan pada CATIA V5 tersebut, dilakukan analisa tegangan Von Mises dan displacement yang terjadi pada 3 variasi mesh dan variasi beban 2550 N, 2648 N, 2746 N, 2844 N, 2942 N, 3040 N, 3138 N, 3236 N, 3334 N, dan 3432 N. Hasil analisis tegangan Von Mises dan displacement pada 3 modifikasi pegas daun dengan variasi 3 mesh dapat disimpulkan bahwa perbandingan antara tegangan von mises dan variasi beban adalah linier yaitu semakin berat beban maka tegangan von mises akan semakin besar dan semakin banyak elemen maka tegangannya juga semakin besar. Pada 3 modifikasi pegas daun yang telah dibuat bahwa pegas dengan tanpa alur pada modifikasi 1 memiliki tegangan von mises paling tinggi dibandingkan dengan pegas daun yang dibuat beralur/slot. Dan pegas daun modifikasi 3 yang menggunakan 1 alur/slot menghasilkan tegangan von mises dan displacement yang lebih rendah dari modifikasi 1. Pegas daun modifikasi 2 yang menggunakan 3 alur/slot menghasilkan tegangan von mises dan displacement yang lebih rendah dari modifikasi 3. Keywords: Pegas Daun, Metode Elemen Hingga, Simulasi, Analisa Statik, Von Mises, CATIA

The objective of the research was to propose a 90 degree steering mechanism system. The application of this steering system can be implemented on off-road cars, military vehicles, and city cars. The advantage of the systems is its flexibility in movement. Therefore, the vehicle will have high degree of moving in any direction. The mechanism was designed in 2D and 3D model. Subsequently, the components were joined in assembly and the kinematic simulation was done by using CATIA. Clash detection among the components was carried out in assembly workbench of CATIA. The results of this study will help the automotive industries to develop a real 90 degree steering system. All components were completely designed in 3D solid by using CATIA. Furthermore, the clash among the component in the product assembly could be eliminated by part editing. In the final assembly, none of the clash was detected.

The objective of the research is to design truck frame of 120 PS series. The method used in the research is reverse engineering, by re-designing the existing frames and taking its measurements. The measurement results are then used to design a frame in the CATIA V5 software. After the modeling, it will obtain the three-dimensional design in solid form. Static analysis was then performed to see the truck’s frame strength under the static load. The given loads vary from 8, 10, 12, and 16 ton. Based on the load, the maximum Von Mises stress results are 1.37 x 107 N/m2, 1.98 x 107 N/m2, 2.37 x 107 N/m2 and 3.16 x 107 N/m2 respectively. The maximum stress condition is still in the safe category based on comparison with the yield stress of steel material used of 2.5 x 108 N/m2. While the maximum strain that occurred at each loading was 0.025 mm, 0.0832 mm, 0.0999 mm and 0.133 mm, respectively.

The process of sheet metal forming is one of the very important processes in manufacture of products mainly in the automotive field. In sheet metal forming, it is added a certain size at the die to tolerate a result of the elasticity restoration of material. Therefore, when the product is removed from the die then the process elastic recovery will end within the allowable tolerance size. Extra size of the die is one method to compensate for springback. The aim of this research is to optimize the die by entering a springback value in die design to improve product quality that is associated with accuracy the final size of the product. Simulation processes using AutoForm software are conducted to determine the optimal parameters to be used in the forming process. Variations the Blank Holder Force of 77 N, 97 N, and 117 N are applied to the plate material. The Blank Holder Force application higher than 97 N cannot be conducted because the Forming Limit Diagram indicates the risk of tearing. Then the Blank Holder Force of 37 N, 57 N and 77 N are selected and applied in cup drawing process. Even though a few of wrinkling are appear, however there is no significant deviation of dimension between the product and the design of cup.

Dissimilar welding of aluminum is an innovation used to increase the effectiveness and efficiency in making a product or component. It has been applied on the automotive industry, aerospace, and shipbuilding. Aluminum has low weldability in compared with steel material because of the oxide layer on the surface of aluminum. The welding problems of aluminum can be overcome by using a solid state welding such as friction stir welding (FSW). The objective of this study was to determine the strength of the welding joint and the microstructure of dissimilar welding joint with different series of aluminum. The tensile testing was performed with the weld directions of 0° and 45° to assess the formability, hardness testing, and microstructure of FSW. In this study, welding process was conducted to combine aluminum 1100 series (low strength aluminum) and aluminum 6061-T6 series (high strength aluminum) in the 2 mm thickness of aluminum sheet. The analysis was done by making comparison of the strength between dissimilar and similar aluminum series. The results showed that the dissimilar weld types, both in angle orientation of 0° and of 45° had fracture location on the HAZ area of 1100 aluminum series. The highest results of tensile strength were 78.07 MPa and 75.26 MPa for weld angle orientation of 0° and 45°, respectively. Weld angle orientation had significant effect to the strain where value of the welding direction of 0° was 10.99% and of 45° was 13.8%. Hardness test in the weld zone generated diverse values because the material stirring was not homogenous, whereas the similar welding was more stable in the welding area. Microstructure investigation on the dissimilar aluminum welding found a hook defects in the weld nugget. In the HAZ area, the grain size of 6061-T6 increased while of 1100 material decreased. It might be affected by the temperature and the aluminum characteristic. Meanwhile, in weld nugget, the grain size increased due to the stirring tool joint and heating during the welding process.

Brass is an alloy between copper (Cu) and zinc (Zn) where the majority of the elements are copper. Brass that undergoes a cold rolling process will experience changes in microstructure and mechanical properties. This study aims to find out the effect of cold rolling process on changes in microstructure and hardness of brass. The composition of brass is analyzed by using Energy Dispersive Spectroscopy technique, while microscope optic is used to obtain microstructure photograph of brass. The hardness of brass is measured before and after cold rolling process. The test results show that cold rolling process causes the increase of hardness on brass, change of grain shape, and the appearance of deformation bands on brass.

The objective of the research is to design the outer rear door of Esemka Rajawali 2 by using reverse engineering method. Esemka car is one of the national cars being developed in Indonesia. Esemka Rajawali 2 has a Sports Utility Vehicle (SUV) model with 1.6L engine version, 1,597 cc inline DOHC. Reverse engineering method is used to obtain geometry data from the existing products and to reconstruct into three-dimensional drawing model. The three-dimensional model is used to design the mold or dies. Dies design is done by using CATIA V5 software. The process of die making plays an important role because it will be produced with a variety of car body components with particular desired shape. Design of a car body consists of various models, shapes, and construction. After the mold designs are completed, static analysis was done to determine the stresses that occur in the mold. This research has succeeded in modeling a three-dimensional model of the rear door using reverse engineering method. The dies design was successfully created using CATIA V5 software. From the static analysis results, by employing a maximum load of 50,000 N, the mold is still in a safe condition based on the yield stress of the used material.

In this paper, a dynamic explicit method was used to simulate U-bending processes of aluminium and its springback. The simulation was carried out using a free software of finite element analysis code namely Impact. The model was taken from a benchmark model in Numisheet'93. The numerical results of the dynamic explicit code were compared with the results of the experimental works. After the optimization was done using the simulation process, it was found that the springback results showed a good agreement with that done by the experimental results. The software Impact was capable of simulating the U-bending processes and predicting the occurrence of springback.

Tailored welded blank (TWB) consists of steel sheets of different thicknesses and strength which welded into one sheet to reduce weight and production costs, to increase dimensional accuracy and strength. Since a tailored blank is composed of different sheets of metals having different thicknesses and properties, the forming of tailored blanks then creates a lot of technical problems especially in the scheme of deformation. The objective of this work was to evaluate the drawability of tailored blanks. In order to assess the forming behavior of the tailor-welded blanks under the influence of weld orientations, a finite element and experimental methods were conducted. Three welded specimens with weld lines oriented at an angle of 0°, 90° and 45° with respect to the direction of load were investigated. The finite element result showed in a good agreement with the experimental result. The result of the experiment showed that a welded part was characterized by a higher strength and lower plasticity compared to those of the base material. Hence, the weld influences the strain distribution of the tailor-welded specimens. This phenomenon depends strongly on the direction of the weld against the direction of tensile load. The lowest strains occur in the specimen with a longitudinal weld.