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Uređaj za prihvatanje semena drveća
No full textUređaj za prihvatanje semena drveća je namenjen primeni u semenskim objektima. Sastoji se od parova ploča (1), povezanih šarkama (2), koji se spojnicama (3) i vijcima s navojnim maticama (4) postavljaju oko stabla u vidu prstena.Patent RS 1835 U1 je objavljen u Glasniku intelektualne svojine br. 25/1. Spis malog patenta je priložen, a ovde je i link: http://pub.zis.gov.rs/rs-pubserver/pdf-document?PN=RS1835%20RS%201835&iDocId=105702&iepatc
CAVITATION RESISTANCE OF TALC-REINFORCED PYROPHYLLITE CERAMICS
No full textThe paper describes the effects of changing the properties of pyrophyllite ceramics reinforced with different
proportions of talc (%): 10; 20; 30. Pyrophyllite powders with a grain size of 20 μm and talc powders with
a grain size of 15 μm were homogenized, pressed and sintered at a temperature of 1200⁰C. The cavitation
resistance of the sintered samples was determined by the ultrasonic vibration method with a stationary
sample according to the ASTM G32 standard. The evolution of surface morphology and damage was
examined by scanning electron microscopy (SEM). The aim of the research was to obtain a compact
ceramic with improved properties of resistance to wear and cavitation. The quality of the sintered samples
was evaluated according to the values of cavitation rates and the analysis of the surface damage
Mould Realization and Technology Development for Different Biocomposite Specimens (Mycelium-Based Materials): Case – Three-Point Bending Test
No full textThe idea of this paper is the application of biomaterials in construction, primarily as thermal insulation materials. It is necessary to prepare biocomposite specimens to test their mechanical characteristics and behavior. This work prepared the specimens for three-point testing bending following the corresponding standards ASTM D790 (three-point bending) and ASTM D7264 (flexural stiffness and strength properties). Firstly, a 3D polymer mold prototype was developed and manufactured. After that, the technology of the biological process of the production of mycelium-based composite materials was carried out according to the appropriate procedure, where three different types of substrates with two types of granulations (fine and coarse) were used. Specimens (or plates) with a reinforced structure (where the moisture percentage was reduced to a minimum) were obtained and prepared for the mechanical characteristics testing.contract No. 451-03-65/2024-03/20010
Experimental Assessment of PA6 Bearing Housing Pressed-Fit for Enhanced Reliability and Multiple Maintenance Process
No full textThis paper presents an experimental method for determining the suitable bore diameter of bearing housings made of polymer designated as PA6, which enables multiple bearing replacement processes. Preceded by analytical calculation, four distinct series of housing samples (each with varying production tolerances) were subjected to testing, where each series comprised three housing samples with identical tolerance specifications. The assembly and disassembly processes of press-fit joints were thoroughly monitored using a force sensor, complemented by equipment for measuring the roughness of contact surfaces. Based on the experimental findings, a recommendation is provided for an appropriate interference fit for the tested bearing housing, providing a suitable solution for multiple maintenance processes. As a summary, the idea of this research is to define the prototype solution for the interference fit of a rolling bearing installed in a PA6 housing. Methods used to examine the proposed solution were surface topography and roundness measuring of PA6 housings, while the press-fitting and dismantling tests of rolling bearings in/from PA6 housings were used to verify it.451-03-137/2025-03/200105 ;
451-03-136/2025-03/20021
Influence of welding parameters on the geometric characteristics of surface weld metal obtained by handheld laser welding
No full textThe handheld laser welding process is the latest innovation in welding technology with an increasingly broad range of applications primarily due to the simplicity of the welder training, the minimal influence of the welder on joint quality, low heat input, high welding speed, and lower equipment costs. In this paper, the influence of selected welding parameters (wire feed rate and laser oscillation width) on the geo-metric characteristics of surface welds on low-carbon steel P235GH is presented. Additionally, based on the selected optimal parameters, a butt joint is performed by welding plates made of the same base material. The dependence of these parameters on weld metal width and weld metal reinforcement is determined. Furthermore, it is concluded that use of a higher power device would most likely be successful in a complete root penetration during butt welding
SOME REMARKS ON THE BASIC PRINCIPLES OF ULTRASONIC WELDING OF CONDUCTORS IN THE AUTOMOTIVE INDUSTRY
No full textThe application of ultrasonic welding has increased over the last decade due to the rapid technological development and its availability at lower cost. In this paper ultrasonic welding of conductors is presented as one of the most important manufacturing processes in the automotive industry. Using this method of welding, conductor joints are created that represent a crucial part of any electrical installation such as wiring harnesses for vehicles. Additionally, connections between conductors and components, such as metal terminals, can also be achieved using the same welding process. These conductor joints or connections between conductors and terminals must provide high electrical conductivity and satisfying mechanical properties in order to create a safe and reliable product. The conclusions of this study provide some advantages of ultrasonic welding application particularly in the automotive industry, and further trends in this field
DYNAMIC FLEXIBLE JOB SHOP SCHEDULING PROBLEM BASED ON GENETIC ALGORITHM
No full textThe increasing frequency and sophistication of cyber-attacks on manufacturing systems demand that scheduling frameworks evolve to include cybersecurity considerations. The integration of dynamic and cybersecurity-related factors into the flexible job shop scheduling problem modelling is essential to better reflect real-world manufacturing conditions. This paper addresses the flexible job shop scheduling problem in a dynamic manufacturing environment, affected by three unexpected disturbances: the arrival of new jobs into the manufacturing system, job cancellations, and machine tool breakdowns. Particularly, some of these disturbances are caused by cyber-attacks targeting manufacturing systems, increasing risks to production and operational reliability. These disturbances have a significant impact on manufacturing efficiency, affecting delivery deadlines, resource utilization, and overall processing time. In this research paper, a genetic algorithm is applied as a robust artificial intelligence technique suitable for solving NP-hard combinatorial problems such as the dynamic flexible job shop scheduling problem. The algorithm facilitates real-time adjustment through rescheduling mechanisms, aiming to achieve a specified optimization objective – minimizing the total processing time (makespan). The proposed method is implemented in the MATLAB® environment and validated through simulations using relevant benchmark problems. Experimental results demonstrate that the proposed methodology significantly improves adaptability and performance in dynamic manufacturing environments, while maintaining high efficiency despite sudden interruptions. Overall, the proposed approach advances intelligent and adaptive real-time rescheduling in a flexible job shop environment, supporting the Industry 4.0 concept by enhancing the flexibility, efficiency, and performance of intelligent manufacturing systems that can withstand both disturbances and emerging cyber threats
Proceedings of the 1st Biennial ESIS-CSIC Conference on Structural Integrity - BECCSI 2025
No full textDear Colleagues, Dear Friends,
It is with great pleasure that we welcome you to our beautiful city of Belgrade (Serbia) for the 1st edition of the Biennial ESIS-CSIC Conference on Structural Integrity (BECCSI 2025). But first, a couple of words about the organisers of this international scientific event - the European Structural Integrity Society, the China Structural Integrity Consortium and the co-organiser, the Society for Structural Integrity and Life “Prof dr Stojan Sedmak”.
The China Structural Integrity Consortium (CSIC) is a non-profit academic organization committed to promoting academic exchanges, advancing scientific research, facilitating engineering applications, and disseminating knowledge specifically in the realm of structural integrity. Its origins can be traced back to 2002, spearheaded by a consortium of universities and research institutes that have historically participated in joint research focused on structural integrity, especially concerning the safety technology of pressure vessels and pipelines. In 2003, the inaugural International Fracture Mechanics (FM) Symposium took place in Shanghai. As the discipline and its application areas broadened, the FM series of conferences transitioned in 2010 to the International Symposium on Structural Integrity (ISSI), with member institutions rotating the responsibility of organization. In November 2012, following extensive discussions and consultations among the Materials Division, Pressure Vessel Division, and Failure Analysis Division of the Chinese Society of Mechanical Engineering, the decision was made to collaboratively establish the CSIC. The latest ISSI took place in Dongguan from November 5th to 8th, 2024.
The European Society for Structural Integrity (ESIS) is an esteemed international non-profit engineering scientific society. Its primary mission is to foster and enhance knowledge surrounding all facets of structural integrity and to disseminate that knowledge widely. The overarching goal is to elevate the safety and performance of structures and their components. The origins of the European Structural Integrity Society can be traced back to November 1978 during a summer school event in Darmstadt, Germany. Initially, it was known as the European Group on Fracture. From 1979 to 1988, several technical committees were established, with the Elasto-Plastic Fracture Mechanics committee being the first among them. The initial vision was to emulate the work of the ASTM committee in Europe. Dr. L.H. Larsson from the European Commission Joint Research Centre served as the inaugural president of the European Structural Integrity Society. Currently, ESIS comprises a total of 24 technical committees and national groups across all European countries. The present president of ESIS is Prof. Aleksandar Sedmak from the University of Belgrade in Serbia.
The Society for Structural Integrity and Life (Serbian Društvo za integritet i vek konstrukcija "Prof. Dr. Stojan Sedmak", or simply DIVK) is a non-governmental, non-profit society of experts engaged in the practical application of the theory of fracture mechanics. Founded in 2001, today the Society has more than 240 registered members and engages in a number of activities such as seminars, publications, cooperation with other societies, and more. The journal "Structural Integrity and Life" is published by DIVK. The Society aims to master contemporary theoretical, numerical, and experimental methods for structural integrity assessment in order to apply them to ensure in-service safety and reliability and to extend their design life, enable the prevention of failures to minimize the risk of endangering human lives and polluting the environment, and improve the level of education and publishing in the field
DEVELOPMENT OF A 2-AXIS SCARA ROBOT MOTION CONTROLLER BASED ON MCU
No full textThe robot systems are designed and developed in such a way that they can successfully realize the specified task. Robot control systems must enable control of robot movement and all other activities necessary for completing the programmed tasks. One of the most important parts of any robot is its motion, and precise control in real-time. This paper proposes the development of a robot motion controller based on the MIKROE MINI-M4 development board with the STM32F415RG microcontroller. Research related to the field of motion controller development presented in this paper includes the realization of interpolation tasks in joint coordinates (PTP control) and interpolation of linear path segments in world coordinates (CP control). To perform these tasks, a mathematical model of interpolation in joint and world coordinates of a two-axis robot with non-trivial kinematics is introduced. The interpolator model is developed so that the joints' or the end-effector's velocities have a trapezoidal profile. To achieve the required trapezoidal velocity profile, synchronized control sequences are generated as a series of pulses with appropriate frequencies for each axis. As a verification, before implementing the mathematical model into the motion controller, simulations of the mathematical model itself and the robot's motion in the joint and world coordinates are performed in the MATLAB environment. The motion controller is implemented on the aforementioned development board with a microcontroller (MCU) using the MIKROC programming environment. The series of pulses with appropriate frequencies is tested on an oscilloscope as the first verification method of the realized motion controller. Reference points of movement defined in joint or world coordinates are obtained by interpreting the program in the MATLAB environment and transferred via serial communication to the MCU with integrated motion control using the MIKROE EasyPIC V7 development board. Experimental verification of the developed motion controller was performed by laser engraving the programmed trajectory of the robot end-effector according to the desired PTP or CP motion control
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