Machinery - Repository of the Faculty of Mechanical Engineering, University of Belgrade
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Static Calculation of Container Structure Loaded by Wind and Snow Using the Finite Element Method
No full textThe paper describes analytical and numerical methodology analysing the stress state of structural elements of the
special-purpose container. Research is based on the container supporting structure and the stress state under the
effect of additional loads from wind and snow is determined. Numerical analysis is carried out using the finite
element method in the ABAQUS® software package. After
the numerical calculation, it is concluded that the designed
container will not reach a critical condition due to additional loads. Some of the safety issues should be considered
early in the container life cycle, already during design and
manufacture. It is usually required to apply measures for
safe and healthy work which are determined by regulations
in the field of safety and health at work, and in connection
with the work to be performed
Positioning of Architect in Emerging Architecture
No full textThis research investigates the evolving role and positioning of the architect within data-driven and artificial intelligence design processes in emerging architecture. As digital thinking continues to reshape architectural practice, the study explores the intersection between computational approaches—exemplified by the “digital chain” as the direct design-fabrication connection (Hovestadt, 2005), AI and traditional, analogue design methods. Through qualitative inquiry, including a focus group of digitally engaged architects, the study emphasizes the enduring relevance of human-centric skills such as intuition, empathy, and creativity in an increasingly algorithmic design environment.
Positioning is interpreted both as the architect's evolving role and their influence within design-realization cycles. Drawing from theorists such as Negroponte, Schoen, Carpo, Lawson, Cross, Leach, and Colomina, the research frames architecture as a hybrid space where the human factor remains an unpredictable yet essential force. Computational design is viewed not merely as automation but as an extension of natural intelligence, enhancing creative potential through artificial intelligence.
Through the lens of leading digital practitioners—Gramazio & Kohler, Burry, Aish, and Menges—the research identifies a shift in architectural authorship: from isolated design stages to integrated, continuous involvement across ideation, digital tooling, and fabrication. Key findings include the redefinition of digital methods through traditional integration, the architect’s expanded control over realization, and the necessity for new competencies among digitally professionals.
Rather than prescribing fixed roles, the study proposes flexible “zones of influence” with(in) the digital and artificial. It argues that architects must act as conduits between human insight and machine precision—preserving creative identity while navigating the demands of a data-driven and AI, collaborative, and technologically mediated future
IMPLEMENTATION AND OPTIMIZATION OF THE DELTA 3D PRINTER CONTROL SYSTEM
No full textThis paper deals with the implementation of a control system for a Delta 3D printer, which was carried out to enable its use in educational applications. A detailed diagnostic was performed on essential hardware components of the Delta 3D printer, including the Arduino MEGA, RAMPS 1.4 board, stepper motors and their drivers, micro switches, display module, and other electronics. A customized version of the Marlin firmware, adapted for a Delta configuration, was then installed on the Arduino MEGA microcontroller. Key parameters such as build plate dimensions, print height, Delta radius, motor microstepping, and maximum motor speed and acceleration were configured. To optimize stepper motor performance, reference voltages were adjusted, and TL smoothers were installed to ensure stable and quieter operation. The final system evaluation included measuring motor voltage levels, verifying filament flow rates, checking the dimensional accuracy of printed parts, and validating the parameter setup. After hardware and firmware calibration, various slicing software tools available online were tested and compared. The aim of the analysis was to identify the most suitable slicing software for the optimized Delta system, as well as the optimal configuration of its parameters, in order to achieve the highest possible print quality
Analysis of the effect of undercuts in misaligned welded joints
No full textThe goal of this paper was to investigate the effect of undercuts, combined with other weldingdefects, onthe integrity of welded joints, and was inspired by previous work on the subject of welded joints withdiffernetdefect combinations. Research presented here relied on the fracture mechanics principles, namelytheFailureAssessment Diagrams (FADs), which was used to determine critical crack lengths, assuming a crackwhichhad initiated in the weld face undercut, for two different cases, both of which had vertical plate misalignmentas one of the defects. Based on the obtained results, it was concluded that a crack in the undercuts was safe, showinggoodagreement with actual behaviour of misaligned specimens during tensile tests. Actual failure of speci<menswith such defect combinations, as determined by experimental and numerical means, would occur inthevicinity of other defects, such as incomplete root penetration
PSO-BASED RESONANT CONTROLLER FOR TRAJECTORY TRACKING OF ROBOT MANIPULATOR
No full textThis paper addresses the problem of path following for robotic systems. Specifically, a robot manipulator with three degrees of freedom must consecutively track an elliptic curve in space while adhering to a prescribed velocity law. Given that robots are highly nonlinear mechanical systems, achieving this objective is a complex task. Therefore, the mathematical model of the robot manipulator is transformed into a more manageable linear form, based on the actuator dynamics. To achieve high-accuracy path following, a model-based resonant controller is proposed. While this type of controller is not novel within the control community, its application in robotics remains relatively unexplored. To minimize tracking error, a particle swarm optimization (PSO) algorithm is employed, with an appropriate objective function designed to achieve the desired goal. The primary contribution of this paper lies in the integration of this metaheuristic algorithm with the complex resonant controller. Extensive simulations are conducted for various velocities of the robot’s end-effector, and the results are consistent with the expected dynamic behavior.451-03- 137/2025-03/200105 from 04.02.2025
451-03-137/2025-03/20010
Cavitation erosion damage of pyrophyllite samples reinforced with cordierite, mullite and zirconium-silicate
No full textThis study investigates the cavitation erosion resistance of pyrophyllite-based composites reinforced with 20 wt.% of cordierite, mullite and zirconium-silicate, sintered at 1200 °C. The phase composition and microstructural features of the sintered samples were analyzed using XRD and scanning electron microscopy (SEM). Cavitation resistance was evaluated using the ultrasonic vibratory method with a stationary sample according to ASTM G32, by monitoring the mass loss and surface degradation as a function of exposure time. The results show that the addition of refractory phases with higher hardness significantly improves the cavitation resistance of pyrophyllite. Among the investigated compositions, the sample reinforced with cordierite (P+C) exhibited the lowest cavitation rate (0.145 mg/min) and minimal surface damage, attributed to its compact and homogeneous microstructure that suppresses microcrack initiation and propagation. The samples containing zirconium-silicate (P+Z) demonstrated moderate improvement, while mullite-reinforced samples (P+M) showed the least enhancement due to their elongated grain morphology facilitating brittle fracture. These findings indicate that cordierite is the most effective reinforcing phase for improving the cavitation durability of pyrophyllite-based ceramics, enabling their potential application in hydrodynamic systems exposed to cavitation-induced wear
A mathematical model of the effect of pitch angle on power performance of a small HAWT
No full textOptimization of wind turbine aerodynamic performances implies solving the problem in the domains such as airfoil selection, blade rotation angle, number of blades, etc. The current article studies the effect of blade rotation angle (β = 5, 7 and 10°) at the flow velocity in the wind tunnel (Vw = 5.8; 8.3 and 11.5 m/s) and a specific number of revolutions on the horizontal axis wind turbine – HAWT output power. The experiment involved two models of blades. Based on planning the experiment, mathematical models were created to be applied in practice. The highest number of revolutions (n = 192 RPM) and generator output (P = 18.8 W) were achieved at the velocity of Vw = 11.5 m/s and β = 10°
Influence of Geometry Parameters on Shaft’s Load-Carrying Capacity
No full textThe load-carrying capacity of shafts is an important feature in the design and performance of machinery. This paper presents a comprehensive study aimed at understanding and quantifying the influence of geometry factors, including shaft diameter and the position of load between shaft supports, on the shaft’s load-carrying capacity. The load-carrying capacity criterion is the fatigue safety factor. This paper offers a systematic exploration of the influential geometry factors affecting shaft load-carrying capacity, individually and in combination. The paper concludes by considering the simultaneous influence of all the aforementioned factors. A new factor is introduced, representing the effect of geometry parameters. This factor allows for a holistic approach to shaft design, enabling engineers to make informed decisions that maximize load-carrying capacity with the changing geometry of shafts
Modelling and Simulation of an Electromagnetic Vibratory Actuator Using CAD Software
No full textThe paper presents a model of an electromagnetic actuator that is used as an excitation element of vibratory conveyors and feeders. Considering the nonlinearity of the electromagnetic actuator, it is important to investigate its model and perform certain simulations. The model was checked with the EMWorks simulation package. Key simulation results are presented at the end of the paper.IEEE Catalog Number: CFP25JAH-ART
ISBN 979-8-3315-1579-
Тablice za proračun protoka vode kroz hidrantsku mlaznicu
No full textU nizu merenja koja su izvršena u Centru za protivpožarnu tehniku Mašinskog fakulteta u Beogradu je pokazano da se protočne karakteristike mlaznica koje se danas prodaju na našem tržišu i koje ispunjavaju uslove propisane standardima SRPS EN 671-1:2015 i SRPS EN 671-2:2015 bitno razlikuju od protočnih karakteristika koje se dobijaju prema standardima SRPS Z.C1.050:1989 i DIN 14 200:1979. U okviru ovog rada biće predstavljene tablice u kojima je protok vode na mlaznicama prečnika usnika 12 mm i 16 mm u funkciji od pritiska, za različite protočne karakteristike.На првој страни су погрешно одштампана имена аутора.
Тачна имена су на последњој страни