World Conference on Mechanical Engineering

Homogeneously cooling performance in passenger buses with large interior volumes is an increasingly important issue for passenger comfort. Due to large interior volume in passenger buses, cabin cooling may take a long time to provide the cabin regime temperature. For this reason, it is getting more important for passenger comfort that cooling cycle in the air conditioning unit located in the ceiling section of passenger buses should work in optimum condition and safely. In this study, a bus developed by ANADOLU ISUZU has experienced an increase in the compressor output pressure value with the increasing refrigerant temperature in cooling circuit activated the air conditioner, and a decrease in the cooling load to be sent to the cabin has occurred. There are many variables for improvement of the refrigeration cycle, and this will increase the time spent on the improvement. It is aimed to produce solutions with minimum variables. For this reason, CFD simulations were carried out in Ansys FLUENT 2020 software to intake more air in the condenser and reduce the temperature of the system circuit. For the simulations, the temperature of the cycle was reduced by using the RANS equations. With the work done, this study provides a development purpose for many new vehicles that will be released to the market.

In a Class-III commercial vehicle project to be produced by Anadolu Isuzu company, data obtained from lane change and bump pass tests performed with a prototype vehicle, virtual vehicle model verification studies were carried out with a virtual vehicle model created as part of R& D studies. In order to be able to perform the physical tests performed on the prototype vehicle in a virtual environment, the same road models were also created in virtual conditions and virtual tests were performed using the MSC Adams/Car program. Since the characteristics of the wheel installed on the test vehicle are not fully known, it will be able to differ depending on the wheel used in the virtual model. Especially in the lane change test, the reaction of the wheels and the driver's behavior will affect the test data. In order to evaluate the data decisively, it is aimed to verify the peaks between the maneuvers. In addition, the method of obtaining values appropriate to the test data by changing the wheel parameter values that most affect the lateral sliding angle of the wheels with the help of pSeven optimization software was followed. The minimum and maximum lateral slip angle values obtained in the test results were determined as the target and optimization analyses were performed. Vertical displacement values of the chassis were compared and verified with 4-poster virtual analyzes. As a result of virtual analyses, the virtual vehicle model was verified with test data by providing competencies at certain speeds in wheel center movement, damper displacement, chassis vertical displacement changes and lateral slip angle values.

Significant efforts have been made in the past decade in fitness-for-service (FFS) and Engineering Critical Assessment (ECA) procedures, that provide a concise framework to relate crack size with applied loading using failure assessment diagrams (FAD) to evaluate the severity of crack-like flaws. These approaches rely in the use of fracture toughness data measured from deeply notched specimens under bend loading to guarantee high levels of stress triaxiality which drive the fracture process. Annex N of BS 7910 procedure describe the methods of including in-plane constraint in the analysis of engineering structures containing flaws that provide conservative acceptance criteria. Most real structural components such as offshore pipelines have small in-plane or out-of-plane dimensions that could cause a reduction in crack-tip constraint to a sufficient amount leading to an increase in effective fracture toughness of the components. The transferability of experimentally measured fracture toughness data to structural piping components therefore, remains essential in accurate predictions of in-service residual and remaining life of these components. As part of efforts to validate these procedures for shallow-cracked specimens, fracture tests on API 5L X65 pipe steel for pin-loaded single-edge notch tension (SENT) and three-point single-edge notch bend (SENB) specimens was carried out at room and -120℃. The results were indexed in terms of the fracture parameter J and the constraint parameter, T. The knowledge gained can be used to develop fracture mechanics methodology and selection of suitable specimens for testing of cracked pipes.

Human emotions and behavior are important factors that impact driving safety. To address the issue of emotional instability in driving, an algorithm was developed to identify human emotions. The study involved data collection from 20 volunteers, and the obtained data was compared with trained data to evaluate the effectiveness of the algorithm. The results indicated a high level of precision and accuracy of the proposed algorithm in recognizing three primary emotions: happiness, sadness, and anger. The accuracy and precision of the algorithm were measured using a confusion matrix approach, which compared the expected and confirmed readings of the system for each emotion. This study provides a foundation for further research to expand the range of emotions that can be detected and to improve the accuracy of the system. Future research could also explore the use of additional data processing techniques and more comprehensive datasets to enhance the system's effectiveness. The development of such systems can help mitigate the risk of accidents caused by emotional driving and improve road safety.

Due to the evolution of the global market and the progress of studies in the investigation for new renewable methods for obtaining energy and ways to minimize the emissions of gases produced by industrial activity, in the exploration for more efficient and sustainable resources for energy distribution and storage, hydrogen is an element of paramount importance to be studied and evaluated. Therefore, the reference work aims to evaluate the perspectives of hydrogen production in Brazil. Firstly, the current Brazilian scenario of hydrogen production was evaluated, which follows the global trend, having in its large part of hydrogen production from the reform of natural gas, also called gray hydrogen, focusing on the refining and fertilizer sectors that, in general, makes use of processes with high carbon dioxide emissions. Next, the prospects of hydrogen production in Brazil over the years will be analyzed. Thereby, it is concluded that Brazil has a prominent position to become an exporter of low-carbon hydrogen, since it presents excellent and favorable climatic conditions for electricity generation through wind, solar and hydro sources.

The process of firing with a weapon system is a complex thermodynamic and mechanical one. For the case of a multiple guided / unguided rockets weapon systems, the structure of the platform is subjected to considerable efforts. The purpose of this research article is to optimize the firing process when launching multiple unguided rockets from LAROM platform, a Romanian mobile multiple unguided rockets launcher that can operate with the standard 122 mm rockets, as well as with the more advanced 160 mm rockets. The variant firing GRAD 122 mm rockets, with a strike range up to 20 km was considered for the evaluation. The authors calculated, for different scenarios of rockets launched, the minimum forces, moments and oscillations. The assessment took into consideration the induced forces on the launch facility (tipping part, chassis). Having the theoretical results, conclusions could be drowned regarding the optimization of the firing process for the launching scenarios considered. The optimization is performed for the launch order determinations, considering the rockets available on the pods, and for the time required between the launchings.

In the contemporary context, drawing a clear line between internal and external security in current operations can be challenging, given the prevalence of asymmetric threats. Thus, armed forces and internal security institutions frequently perform similar duties, so both need a broad range of equipment and capabilities. For example, the inability of the defense troops to carry out highly complex night combat actions led to the development and use of pyrotechnic illumination systems and, subsequently, night vision equipment. These illuminating devices are generally developed to secure camps and protect borders. This research focused on developing heterogeneous mixtures used as pyrotechnic compositions in illumination systems. Thus, various composite formulations based on barium nitrate (as oxidizer), magnesium powder (as metallic fuel), and a polymeric binder (polyurethane/polyurea) were obtained and characterized through specific analytic investigations. The innovation of this research consists of environmentally responsible pyrotechnic formulations, incorporating a ‘green’ blend of polyester-polyols obtained from recycling polyethylene terephthalate waste. In addition, the polyurea/polyurethane binder will improve the processability of these energetic mixtures and minimize the risks associated with the manufacturing process. Both newly developed and conventional pyrotechnic compositions were comparatively analyzed to assess the improvements brought by the introduction of the binder, in terms of safety and performance.

This paper deals with the subject of finite element modeling of the impact phenomenon between hard penetrators and plates made of High Entropy Alloys (HEAs). For many years, alloying has been employed to give materials desirable qualities. Experimental determinations of the mechanical response of the material at high strain rates by simplified constituent laws are conducted using the Hopkinson Bar System, the method consisting on evaluating the difference of the mechanical impedance between the sample and the bars of the installation. The elastic wave generated by the impact passes through the incident bar, reaching the specimen, at which point a complex process of transmission/reflection is taking place. Due to the fact that experimental impact conditions in the studies were specific to the normal impact, at 0 degrees, the virtual models were made in LSDYNA, 2D axially symmetrical. During the simulation, plastic-kinematic type material models were use, using as input data the values resulting from the static and dynamic characterization tests of the HEA like materials obtained. The simulation results were consistent with the observed experimental results.

The present work is an investigation of the reacting nozzle flow for a rocket engine using liquid oxygen and methane as propellants. The RL10A-3-3A rocket engine is selected as the baseline of this study, due to the availability of its nozzle profile. The simulations in this study were carried out using the commercial CFD software ANSYS Fluent. The first case is the simulation of the actual rocket engine nozzle flow with hydrogen. For this case, the reduced Evans and Schexnayder reaction model, with 6 species and 8 reactions, is used. Keeping the same chamber pressure, methane is then used as fuel instead of hydrogen for the second case. The third case is for a much higher chamber pressure using methane. A reduced model of the reaction mechanism for oxygen/methane combustion, with 8 species and reactions, is employed. A comparison of the obtained results for the three cases shows that the expansion of the hot gases produced in the combustion chamber through the nozzle is much more important for the hydrogen case compared to the methane case. Nonetheless, a much higher chamber pressure improves the hot gases expansion of the methane case. Finally, results show that liquid methane can be a viable replacement for hydrogen as a reusable rocket propellant.

In order to improve the hardness and wear resistance of the thermally sprayed NiCrCoFeCBSi/40 wt.% WC coating, a transverse oscillating laser beam technique was applied for the post-remelting the coating. A single-module optical fiber laser was used for the experiments: power - 300 W, power density - >9554 W/cm2, laser speed - 250-1000 mm/min, transverse oscillation amplitude – 0 mm, 1 mm and 2 mm. The molten pool geometry and microstructure of the samples, hardness and tribology of the processed layers were investigated by applying scanning electron microscopy, energy dispersive spectroscopy, Vickers hardness measurements and “Ball-on-Disc” dry sliding tests. Oscillating laser treatment with 1 mm amplitude, 250–750 mm/min laser operating speed and preheated samples up to 400 °C gave a satisfactory result. Wide and shallow melt pools were obtained with a depth of about 200–350 µm, a hardness of about 1100–1200 HV0.2 and minimal cracks. Compared to the furnace remelted coatings, laser beam oscillation and preheating coatings increased hardness and wear resistance by ~2.8 times and ~2.9 times, respectively.

This international research project is focused on Artificial Intelligence assisted design scenarios for the bio-inspired and evolutionary algorithm-driven Water-Energy-Food Nexus masterplans for future carbon-positive infrastructure, landscape, and buildings in Greater Miami Islands. The scenarios align with the Paris Agreement of the 21st International Conference of Parties (COP 21), and the UN framework convention on Climate Change (UNFCCC) supports professional, municipal, architectural and urban design practices that reduce greenhouse gasses by operating cities with zero carbon emissions. In addition, Miami benefits from several large-scale grants focused on strategic solutions for adapting to global warming, sea-level rise, flooding, hurricane impacts, heat waves, and saltwater intrusion. This research paper presents the critical results of a research effort through a transdisciplinary, four-year research project funded by European Union Horizon 2020, EU Belmont agencies and the U.S.-National Science Foundation (NSF), working in collaboration with numerous partners globally. It critically compares transdisciplinary methods, AI-ML-driven experiments, and coding for bio-inspired scenarios for infrastructure, architectural, and city scales from 2018 to 2100 and beyond. All iterative methods include the Parametric Open Data integration workflow and bio-scripting synthetic biology growth computational approaches. These methods quantified social and economic impacts from SLR and storm surges for designing adaptive, blue-green infrastructure and buildings from 2018 through 2100. The paper's critical comparison of the results of several methods and open-access synthesis is the development and comparison of several combined scenarios of different sizes for different units and locations in the low-lying areas of Miami.

AI-assisted Generative Design (GD) with genetic (GA) and evolutionary algorithm (EA) methods, digital twin modeling, and topology optimisations (TO) have undergone tremendous developments in recent years due to their essential applications in many fields of industrial and product design, medicine, synthetic biology, infrastructures, automotive technology, aviation, architecture, engineering and construction industries. The paper discusses an awarded realization project of an AI-assisted generative competition design with evolutionary topological optimisation and cloud computation workflows for a fabricated Steel Bridge. The structural analysis and fitness-tested geometry generation are for a 50 m robot 3d stainless steel bridge mixed with low-cost carbon steel components for special EN-Code permitting in Germany. The bridge must be assembled next year in June 2023. The paper questions the sustainability and production characteristics of a 3d-printed bridge versus a lighter hybrid version of prefabricated steel tube geometries and organically robot 3d-printed steel nodes and posts. It will critically describe and compare the performance-based optimisation workflows of this bio-inspired computed 3d Hybrid Wire and Arc Additive Manufacturing (WAAM) steel pedestrian and bicycle bridge. In the future, we aim to make AI-ML-assisted generative design and topology optimisation workflows more efficient in generating outcomes that demonstrate a balance between the designer's artistic (subjective) preferences and the structure's technical (objective) code-permitting requirements. In summary, the paper will critically compare the GD techniques with the GA and EA algorithm workflows with topological optimisations that use natural mechanisms that emulate the behaviors of living systems.

In the present work, we investigate numerically the flow configuration and the Residence Time Distribution (RTD) for a Newtonian fluid between two concentric cylinders. The inner cylinder is rotating and the outer one is maintained at rest with a small axial rate imposed at the inlet. We also consider three different aspect ratios, two for a finite-length cylinder ( , ) and one for an infinite-length cylinder ( ). The Lattice Boltzmann Method (LBM) based on Bhatnagar-Gross-Krook (LBGK) approximation is used to solve the momentum and concentration equations. Two Lattice Boltzmann models are used, the two-dimensional nine velocities model (D2Q9) for the flow field, and the two-dimensional four velocities model (D2Q4) for solving the concentration. The outlet particle concentration is also traced to determine the Residence Time Distribution. The Lattice Boltzmann Method permitted to directly get the particle concentration tracing at the outlet of the reactor, due to its consideration of the time variable (unsteady flow). The obtained results show that the imposed axial flow at the inlet has a significant impact on particle diffusion. Nevertheless, we observe that the longer the reactor gets, the weaker this impact becomes. The Residence time distribution peak has a direct link with the flow rate, which is dependent of the reactor geometry (length).

Basalt fiber-reinforced polymer composites are a good alternative to glass and carbon fiber-reinforced composites in the industry for polymer composites used in aerospace, marine, and automotive. The aim of this study was to investigate failure analysis of filament wound basalt-reinforced plastic (BFR) composite pipes made of Basalt/epoxy with a surface crack under tensile force. The BFR composite pipes were produced of four antisymmetric layers with (±55°)4 winding angles employing the filament wound method. Split-disk tests (according to ASTM D-2290 standard) were performed at a 0° crack angle and the crack-to-thickness ratio of a/t= 0.25, a/t= 0.50, and a/t= 0.75. It was determined that the surface crack of 0° parallel to the axis of the composite pipe reduces the strength of the pipe, and also the strength considerably decreases with the increase of the crack depth. The hoop strengths of BFRP composite pipes that have surface cracks were determined, and the dependence of the hoop strength on the crack-to-thickness ratio was discussed in detail.