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Temporal changes in the flexural properties of 3D-printed ABS specimens
No full textThis study investigates the environmental aging effects on 3D-printed
Acrylonitrile Butadiene Styrene (ABS) produced using Fused Deposition
Modeling (FDM) and Digital Light Processing (DLP) techniques. The
materials in filament (FDM) and resin (DLP) forms were exposed to UV
light, humidity, and temperature fluctuations over two months. Mechanical
testing via three-point bending and Fourier Transform Infrared
Spectroscopy (FTIR) were employed to assess the impact of these
environmental factors. Results showed notable mechanical strength and
structural stability differences between the FDM-printed filament and DLPprinted resin ABS under aging conditions. The filament-based ABS
exhibited superior mechanical properties, retaining its strength over time,
while the resin-based ABS degraded significantly shortly after printing.
Despite exposure to ambient environmental conditions, the chemical
composition of both materials remained stable throughout the research
period.no. 451-03-65/2024- 03/200105; no. 451- 03-66/2024-03/20002
DESIGN AND APPLICATION OF A TWO-PART QUADRANGULAR DEVICE FOR FABRICATION OF UNIFORM TEST SAMPLES FOR BOND STRENGTH TESTING BETWEEN ARTIFICIAL TOOTH AND DENTURE BASE
No full textTo improve the precision and standardization of biomechanical testing of bond strength between artificial teeth and denture bases, an innovative two-part quadrangular device was developed using 3D printing technology (Bambu Lab X-1 Carbon) with polymeric materials. The development was based on a digital model of a scanned artificial tooth (Atos Core 200), which served as a reference for producing uniform and reproducible samples. The lower part of the device is designed for forming the denture base and is filled with wax, while the upper part contains an opening with a specially designed guiding surface matching the dimensions of the scanned tooth, enabling precise positioning at a 90° angle relative to the base. This ensures that each sample is identical in orientation and dimensions, which is crucial for reducing variability in testing. The fabricated samples then undergo a standard dental laboratory waxing procedure identical to the waxing phase of removable denture models. This process ensures full compatibility with real clinical conditions of removable denture fabrication, contributing to the validity and relevance of the obtained results. The unique design of the device allows easy and safe removal of samples without damage, further increasing the reliability of mechanical testing. The produced test samples are then tested on a universal testing machine using a device for bond strength testing under variable loading angles, simulating the complex biomechanical conditions present during functional mandibular movements. This innovative approach enables more precise evaluation of adhesive properties between the tooth and denture base and represents a significant step forward in the development and optimization of removable dental prostheses, with the potential to improve their longevity and clinical reliability
Fractional-order Iterative Learning Control Enhanced Intelligent PID for Articulated Robots
No full textIn the ever-changing landscape of technological advancements, robotics plays a significant part in meeting growing industry demands. Considering the nonlinear, coupled nature and uncertainties of multi-body robotic systems, the ability of articulated manipulators to successfully track the trajectory imposed by a given task is a hallmark of a well-designed control system and remains a crucial aspect of robotics research. Motivated by the potential of control strategies based on the ultra-local models with regard to application in modern robotic systems and recognizing the potential of iterative learning control (ILC) in addressing the repetitive nature of robot manipulation tasks performed by articulated robots, this study proposes a novel control scheme combining an intelligent PD (iPD) controller and a fractional-order iterative learning controller (FOILC). Simulation results with comparative analysis are presented to illustrate the performance improvement and robustness of the proposed controller for the 3-DoF articulated robot
Comprehensive Method For Predicting Gas Turbine Cycle Performances Considering The Impact Of Various Fuels
No full textGas turbines have advanced significantly in recent years, particularly in compressor and turbine efficiency because of aerodynamic breakthroughs based on numerical flow simulations. Additionally, modern energy demands have driven the adoption of alternative, environmentally friendly fuels such as hydrogen, ammonia, and methanol. These fuels significantly influence combustion gas composition, turbine inlet temperature, mass flow, blade cooling, and overall performance. Traditional cycle performance tools often rely on 0D maps for compressors and turbines, which have limitations in simulating these recent advancements. The proposed method replaces such maps with a 2D approach, utilizing detailed flow calculations for compressors and turbines at each operating point. It integrates combustion processes and secondary air systems and iteratively determines the turbine inlet temperature for precise predictions. This method accurately simulates air bleeds, cooling injections, and adjustments in inlet guide and stator vanes while accounting for the effects of fuel composition on performance. This paper demonstrates the methodology using an industrial gas turbine in which natural gas, hydrogen and hydrogen carriers are used as fuels. It shows the consequences of this for several components as well as the main thermodynamic operating parameters. The approach is fast and effective, enabling the optimization of diverse designs throughout development
Investigating the Ability of Turbulence Models to Predict Stall
No full textA detailed numerical study of the flows around the airfoil NACA 23012 near stall, at angles-of-attack ranging between 12.4° and 16.2°, Mach number M = 0.18 and Reynolds number Re = 1.8 million, was conducted by Reynolds-averaged Navier–Stokes (RANS) equations closed by the commonly employed Menter’s k–ω shear stress transport (SST) turbulence model in contrast to the wall-modelled large eddy simulation (WMLES). All these flow simulations were performed in ANSYS FLUENT on the same, sufficiently refined computational mesh with dimensionless wall distance y + ≈ 30. The comparison of the obtained numerical and available experimental results points to the inability of RANS modeling to adequately capture the flow in the post-stall region whereas it performs satisfactorily in the attached, pre-stall region. Although relative errors of lift and drag coefficients remain within an acceptable range, the numerical stall seems delayed or not predicted at all. On the other hand, WMLES manages to reproduce the expected trend of aerodynamic coefficients, while the actual numerical values appear underrated in comparison to the measured values. Both modeling approaches are critically evaluated with regard to the flow separation phenomenon appearing at airfoils at high angles-of-attack and some conclusions are provided
Experimental and numerical analysis of the fatigue fracture behavior of the Ti-6Al-4V alloy
No full textThis paper presents the results of an experimental and numerical
analysis of the fatigue fracture behavior of the selected Ti-6Al-4V
alloy, which was chosen because of its frequent use in industrial
applications.under Contract 451-03-136/2025-03/20021
Sustainable development and circular economy supported by artificial intelligence tools
No full textThis paper researches how artificial intelligence (AI) can support sustainable
development and the circular economy. It focuses on the use of AI tools in resource
optimization, waste reduction, and improving manufacturing processes in line with the
principles of the circular economy. The aim is to demonstrate how AI can contribute to
sustainable practices across industries, from agriculture to manufacturing and recycling,
enabling economies that minimize environmental impact. The study analyzes current AI
technologies such as data-driven optimization, predictive analytics, robotics, natural
language processing, sensor technology and their application in resource consumption
pattern recognition, product lifecycle prediction, and recycling improvements,
considering sustainability principles and environmental issues. While AI offers significant
potential, the paper also discusses challenges such as high implementation costs, the need
for training, and ethical concerns regarding data usage. The conclusion of the study
emphasizes the need for an integrated approach in AI tool implementation, with special
attention to the social, economic, and environmental aspects of sustainable development
A Computational Study on the Influence of Explosive Type on Shaped Charge Jet Velocity in 64 mm Warhead
No full textConstant development of protective materials and armored systems requires continuous improvements in the field of anti-tank ammunition development. One of the most commonly used anti-tank explosive ordnance are shaped charge projectiles/warheads. Serbia has been globally recognized for decades in the production of high-quality hand-held rocket launchers equipped with various calibers of shaped charge ammunition. One of the most famous representatives is the 64 mm hand-held rocket launcher, better known as “Zolja“. Although it has been in use for decades and it has insufficient capabilities against more modern protection systems, retaining the traditional design and long-established production technologies, along with the use of more potent and modern explosives, could significantly enhance its penetration power. This paper uses analytical calculation and numerical simulation to analyze how different explosive materials affect the velocity of shaped charge jet of 64 mm M80 warhead, which ultimately directly impacts its penetration capabilities
50 godina Zajednice za jedinstveno upravljanje proizvodnim i tehnološkim resursima - JUPITER sistem i konferencija
No full textОвај рад представља подсећање и преглед трајања Заједнице за јединствено управљање
производним и технолошким ресурсима, која је познатија као ЈУПИТЕР систем. У циљу научне и стручне верификације резултата истраживачких пројеката и одређивања будућих праваца развoја ЈУПИТЕР система, покренута је и ЈУПИТЕР конференција као научно-стручни скуп чланова Заједнице и других чинилаца индустрије прераде метала, научно истраживачких институција и факултета.COMUNITY FOR UNIQUELY MANAGEMENT OF PRODUCTION AND
TECHNOLOGICAL RESOURCES - JUPITER SYSTEM AND CONFERENCE
This paper presents a reminder and overview of the duration of the Community for the uniquely
management of production and technological resources, which is better known as the JUPITER
system. In order to scientifically and expertly verify the results of research projects and determine the future development directions of the JUPITER system, the JUPITER conference was launched as a scientific and professional gathering of members of the Community and other members of the the metalworking industry, scientific research institutions and faculties
Concept of a reconfigurable CNC machine with distributed control
No full textThe emergence of Industry 4.0 has changed manufacturing by integrating advanced digital technologies, enabling extensive real-time interconnection between information technologies and operational technologies within Industrial Control Systems. This ubiquitous information exchange enables manufacturing systems to operate flexibly and respond quickly to changing market demands and a growing diversity of products. The reconfiguration of manufacturing systems, both physical and functional, is driven by the Industrial Internet of Things, which employ Cyber-Physical Systems as its core enabling technology. This transition initiates a shift from centralized control systems, where a single central unit manages all control tasks, to a distributed control system architecture. Within a distributed control system, the main control task is achieved through the intensive cooperation of smart devices, such as sensors and actuators, equipped with computation and communication modules. In this work, we present a concept of a Computerized Numerical Control (CNC) system with distributed control, based on the cooperation of Low-Level Controllers, which execute local tasks while receiving primary control commands from a High-Level Controller. The proposed approach considers both functional and physical properties to ensure system reconfigurability and scalability