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In the world of the automotive industry there are still several problems that must be resolved, such as what happened in one of the workshops, there was a shortage of tools to repair bent truck frames because of the accident. One of the tools needed to repair the frame is the bending tool, with this the planning process for making the tool has a problem with the ability of the hydraulic tool to be used to repair the frame of the Mitsubishi Center 125. With the simulation method using SolidWorks software, it can be seen that the force load on the frame of the Mitsubishi center 125 will then obtain data that can be analyzed using the finite element method. In the simulation, try to use a force load of 1 ton.f to 20 ton.f at two points, namely the center and side, then can be seen that the displacement of the object that occurs. The results of the simulation are increasing the force load, the degree of change in shape is increasing along with the damage to the object and the highest change of 500 mm so it requires the ability of hydraulic tools that have a compressive capacity of more than 20 tons.

This study explores the geometrical deviations that occur in cold stamping, which are caused by the spring-back effects in elastic metals after forming. The primary aim is to introduce and assess the Combination Approach. This approach seamlessly integrates the Displacement Adjustment and Spring Forward methods for die compensation. This multi-stage process meticulously corrects dimensional errors and effectively reduces spring back through iterative processes. Using the NUMISHEET model, numerical simulations have shown a significant reduction in spring back errors, with up to a 55% reduction achieved with optimized die surfaces after five iterations. The proposed Combination Approach improves the accuracy of die design and contributes significantly to the stamping industry by incorporating established techniques within finite element software. This research broadens the scope of die compensation strategies, creating new opportunities for achieving precise die design in stamping.

This study explores the optimization of membrane reactor configurations to enhance hydrogen production through CH4 tri-reforming. The investigation employs ceramic membranes for oxygen, vapor, and carbon dioxide distribution within the reactor bed. A differential evolution algorithm is utilized alongside cuckoo search algorithm (CSA) and support vector regression (SVR) to determine optimal values for O2/CH4, H2O/CH4, and CO2/CH4 ratios, membrane thickness, and shell pressure, with hydrogen yield as the objective function. Results demonstrate that the oxygen membrane reactor achieves the highest hydrogen yield, reaching 2.02 and 1.75 for direct methanol synthesis and Fischer–Tropsch processes, respectively, representing a 7.98 % and 10.03 % increase compared to the conventional tri-reforming reactor. Furthermore, CSA and SVR emerge as invaluable tools, facilitating robust optimization and predictive modeling. The CSA efficiently navigates complex solution spaces to identify optimal parameters, while SVR accurately models relationships between input variables and hydrogen yield. Incorporating these methodologies enhances the effectiveness of membrane reactor design and synthesis gas production. This study contributes to advancements in clean energy technologies by providing insights into efficient hydrogen production methods using membrane reactors.

The 7th Mechanical Engineering, Science, and Technology (MEST) Conference was held at the Muhammadiyah University of Surakarta, Siti Walidah Main Building, seventh floor, 21–22 December 2023, in the Mechanical Engineering department [...]

The publishers have received certification from the volume editors of the proceedings that all papers published in the conference proceedings of the 7th Mechanical Engineering, Science and Technology (MEST) conference were subjected to peer review, organized by the volume editors [...]

Friction stir welding (FSW) is a pivotal solid-state method revolutionizing metal joining diverse manufacturing sectors. This study explored the transformative potential of FSW in welding various metal types, both ferrous and nonferrous, by its ability to create a minimal heat-affected zone (HAZ), thereby mitigating alterations to the microstructure. This research delved into the utilization of filler materials during the FSW process. The investigation centers on scrutinizing the microstructure within the weld nugget area of FSW, employing a 3.1 mm thick aluminum 6061-T6 sheet in a butt joint configuration. Brass and zinc, each 0.2 mm thick, were selected as fillers. Microstructural analyses conducted via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) specifically targeted the weld nugget and HAZ regions. The EDS analysis revealed a higher presence of zinc fillers within the weld nugget than brass, indicating more evenly dispersed grains. SEM observations also highlighted larger grain sizes associated with brass, which could lead to welding defects such as voids and cracks. As such, the study concluded that using zinc fillers manifests a superior microstructure compared to brass during the FSW process involving aluminum 6061-T6.

This study aimed to investigate the influence of Al2O3 nanoparticle concentration and flow rate on the convective heat transfer coefficient in a heat sink. A testing apparatus was constructed to examine a microchannel heat sink coupled with an Al2O3 nanoparticle fluid. Temperature sensors were strategically placed at the microchannel heat sink’s entrance (T-in) and exit (T-out). Furthermore, a heating element (T-heater) was utilized to monitor the temperature of the nanoparticle fluid. This experimental setup allowed for precise temperature measurements in the system. Aluminum oxide (Al2O3) nanoparticles were thoroughly dispersed in water for 15 min using a magnetic stirrer, resulting in a uniform mixture with concentrations ranging from 0.2% to 1%. The experiments involved altering the flow rates within the range of 0.2 to 1.4 L per minute, enabling the monitoring of temperature changes (T). The heat transfer coefficient positively correlated with escalating concentrations of Al2O3 particles. Incorporating nanoparticles up to a concentration of 1% significantly enhanced the heat transfer coefficient by 17.29%. Additionally, a direct relationship was observed between the heat transfer coefficient and the increase in the flow rate of the Al2O3/water nanofluid. Specifically, when the flow rate was increased from 0.2 to 1.4 lpm, a significant enhancement in the heat transfer coefficient of 29.95% was achieved.

This research aims to determine the effect of the volume fraction of coconut shell composite, with an epoxy matrix at 10% coconut shell water content, on the composite’s tensile strength, impact, density, and fracture results with the macrostructure. The materials used to make this composite are coconut shell particles, with a diameter of 1mm at a water content of 10%, and epoxy matrix and hardener, in a ratio of 1:1. Variations in volume fraction are 10%, 20%, 30%, 40% and 50%. The composite was manufactured using a press mold. Composite testing was in accordance with ASTM standards for tensile testing, using ASTM D 638-02 and impact testing using ASTM D 256-00. Macro photo results that determine the type of fracture that occurred were taken of the fracture resulting from tensile and impact tests. The test results showed that the highest tensile strength was at a volume fraction of 40% of 21.59 MPa, and the lowest was at 10% of 7.15 MPa. The highest impact value was shown in a composite with a volume fraction of 50% of 0.074 J/mm2, and the lowest had a volume fraction of 10% of 0.010 J/mm2. The highest density was a composite with a volume fraction of 50% of 1.067 gr/cm3, and the lowest had a volume fraction of 10% of 1.014 gr/cm3. In observing the fracture after tensile and impact testing, it can be seen that the fracture was brittle, and the direction of crack propagation is perpendicular to the direction of the tensile stress that is acting to produce a relatively flat fracture surface.

The aim of this study is to investigate the thermal performance of water-based Carbon Nano Material (CNM) nanofluids, particularly in the convective heat transfer coefficient (h) parameter, and to analyze the effects of nanoparticle concentration and flow rate on an experimental heat transfer system. To achieve this, the researchers prepared the nanofluid through a 2-step method. In the first step, we mixed the nanoparticles with the base fluid using a magnetic stirrer to ensure homogenization, with the CNM-Water ratio set at 30, 75, 120, and 150 ppm. In the second step, we characterized the prepared samples, determining their size, composition, and particle morphology through PSA and SEM-EDX examination, as well as measuring their density (ρ) and specific heat (Cp). The experiments were carried out using a flow rate simulation test rig with a data acquisition system, at different flow rates of 0.2, 0.6, 1, and 1.4 L/min. Temperature (T) was measured at the inlet, outlet, and heater to determine the convective heat transfer coefficient value. The study successfully investigated the direct impact of CNM concentration and flow rate, with the results showing a consistent and expected value of the coefficient compared to previous studies. The highest coefficient value was observed at 150 ppm CNM-Water ratio and a flow rate of 1.4 L/min, with a value of 1825.37 W/(m2.K).

Abstract Structural rejuvenation is one of the key topics in the field of metallic glasses (MGs). In this work, we evaluated the combined effects of annealing treatment and elastic cyclic loading to discover pathways for promoting structural rejuvenation and improving the mechanical properties in the MGs. Using molecular dynamics (MD) simulations, it was revealed that the sole cyclic loading led to the increase of rejuvenation degree; however, a saturated state was observed upon the 40th cycle. On the other side, the sample exposed to the combined treatment exhibited a slight relaxation at the first step of cycling process and then a sharp rejuvenation degree was detected in the material. The thorough analyses indicated that the change in the fraction of coordination polyhedrons at the relaxation stage was the main reason for the extra rejuvenation in the sample exposed to the combined treatments. The results also suggest that the combination of rejuvenation treatments improves the magnitude of rejuvenation in the amorphous alloys. It should be noted that the increase of rejuvenation in the alloying systems accompanied with a reduction in the tensile strength and an enhancement in the homogenous plastic deformation.