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Several leaks appeared in a mild steel (MS) pipe jet nozzle installed in a direct impact test rig... more Several leaks appeared in a mild steel (MS) pipe jet nozzle installed in a direct impact test rig after a few months of operation in erosive flow at the Centre for Erosion–Corrosion Research. The locations of perforation leaks were primarily upstream, but severe wall thinning was also noticed adjacent to the exit section. In this paper, a failure analysis was carried out on the leaking of a pipe jet nozzle, and the results are discussed in detail. The investigation carried out includes visual observation, scanning electron microscopy, 3D scanning, energy-dispersive spectroscopy, and laser profilometry measurements. In addition, numerical simulations based on computational fluid dynamics (CFD) and the discrete phase model (DPM) were conducted to investigate the root cause of the failure of leaks in the pipe jet nozzle. Further CFD-DPM simulations were performed on three different pipe jet designs for liquid–solid flow conditions, and were compared to find an alternative design to pre...

Nowadays, there are many software packages which make it easy for students and engineers to displ... more Nowadays, there are many software packages which make it easy for students and engineers to display and describe an imaginary idea in better quality, in better sense and in shortest possible time. Therefore, car is designed using the software package Autodesk 3ds Max. Polygonal modeling method was used and designed car represent a new conceptual solution car design. After modeling a car in mentioned software, final digital images are generated too. Final digital images are generated using the Mental Ray rendering tool as a default rendering tool of Autodesk 3ds Max. Attention is given only to the external design of the car, while the interior is not modeled. Furthermore, using the software Ansys Fluent, 2D simulation of the airflow around the side contour of the vehicle was made in purpose of making changes in the geometry of the vehicle to improve the design in terms of reducing air resistance and improve aerodynamics. Most attention of this is given in changing value of angle between the hood and front windshield of car, and analyzing back of the car with and without the rear wing. Also, using the software Ansys CFX, 3D simulation of airflow around the car geometry was made too. Taking into consideration results obtained by 2D and 3D analysis of existing car geometry, a new 3D car model was made. Assumption is that new 3D car model is resulting with better aerodynamic properties. 3D analysis of redesigned car model in terms of mentioned changes is performed too in order to analyze possible improvements.

U radu je dan prikaz sustava oznacivanja celika prema sest važnih europskih normi koje su donesen... more U radu je dan prikaz sustava oznacivanja celika prema sest važnih europskih normi koje su donesene u periodu 1991 do 2002. godine. Prvo su obrađene postavke norme EN 10020 za definiciju i razredbu vrsta celika, a zatim norme EN 10027-1, EN 10027-2 i CR10260 za sustave oznacivanja celika (nazivi, glavne oznake, brojevi celika i dopunske oznake). Dan je i tablicni prikaz oznacivanja nekih važnih celika za strojarstvo po navedenim europskim normama i usporedno po starim HRN i DIN normama.

$Research paper thumbnail of Estimation of Residual Stresses in Pipe-Ring Specimens by Incremental Hole Drilling and X-Ray Diffraction Method$

Experimental Techniques, Mar 22, 2023

Polymers, Jan 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

$Research paper thumbnail of Correlation of Pipe Ring Notched Bend (PRNB) specimen and Single Edge Notch Bend (SENB) specimen in determination of fracture toughness of pipe material$

Fatigue & Fracture of Engineering Materials & Structures, Jan 26, 2017

is well known that pipes or tubes due to their geometry are not suitable for producing standard s... more is well known that pipes or tubes due to their geometry are not suitable for producing standard specimens for fracture toughness testing (e. g. Single Edge Notched Bend (SENB) specimens or Compact Tension specimens. This is especially evident in thin walled pipes or tubes. We propose a new type of specimen, called Pipe Ring Notched Bend (PRNB) specimen, which is ideal for pipes or tubes due to its ring geometry. 1 In the recent years, the authors have made a lot of research on this type of specimen, but cut out from a plate, not from pipes, where some imperfections in the geometry, material, residual stresses, etc. are present. Within this paper, two PRNB specimens (designations PRNB1 and PRNB2) are cut out from pipe which is used in boilers and made from 16Mo3 steel. From the same pipe, four SENB specimens (designations SENB1, SENB2, SENB3 and SENB4) are also made in order to compare the fracture behaviour of standard SENB and newly proposed PRNB specimens.

Lecture notes in networks and systems, Sep 5, 2020

By inspecting the existing constructional designs of boat cranes and the requirements which need ... more By inspecting the existing constructional designs of boat cranes and the requirements which need to be fulfilled, the new constructional design of the boat crane is made. After determining the critical position of the crane in the form of a load, calculation of the inside diameters of cylinders is made and optimized depending on the maximum axial force. Numeric calculation of the stresses and total deformations in software ANSYS Workbench has proved that the design of crane has met all the requirements imposed on the strength. After designing the boat crane and preforming the strength calculations, it is necessary to analyze the motion of the designed crane construction. Boat crane is designed with hydraulic cylinders and rotation around the shaft using a hydraulic motor. Therefore, it is necessary to create a scheme of a hydraulic system of the crane. During the designing and strength analysis, no material exploitation was taken into account and reinforcements were added only to reduce the equivalent stresses and the maximum total deformation of the crane. Due to the possible oversizing of the reinforcements, the optimization was performed by the response surface optimization method. Optimization was performed to minimize the mass and it has been found that the construction was oversized and the mass was reduced by almost 14 kg.

Statistika bibliografskih podataka o projektima, znanstvenicima i znantsvenim institucijama.

The main objective of this paper is numerical analyses of cylindrical pressure vessel with change... more The main objective of this paper is numerical analyses of cylindrical pressure vessel with changeable head geometry (semi-elliptical and hemispherical heads) and comparison of results in means of precision and time needed for getting the solution. Manufacture technology of pressure vessel cylinders and heads are described, and construction geometry of various pressure vessel heads is presented. Discretisation style of finite element models, boundary conditions, and results are detailed shown and explained. Based on analytical solutions for membrane stress state of pressure vessel, numerical analysis of it is performed also. Comparison of harvested numerical results for above mentioned pressure vessels are shown tabular, with values of time needed for getting the solution too. And comparison of analytical and numerical results for pressure vessel with hemispherical heads is shown too.

This paper analyzes the stresses caused by continuous loading at the opposite sides of a long bea... more This paper analyzes the stresses caused by continuous loading at the opposite sides of a long beam. 2D and 3D diagrams of stress distribution Sy based on the terms of the theory of elasticity are designed. Stress distribution Sy is calculated in the middle of beam (y = 0) for different number of Fourier series and the results are presented with 2D diagram. On this basis, Fourier series with a sufficient number of members is determined in order for more accurate results. Further stress analysis is performed using Fourier series with a sufficient number of members. Calculation of stresses throughout the beam height is also performed, and the results are presented in 3D diagram. In order to confirm the accuracy of the results, numerical analysis is performed using the finite element method. Comparison of analytical and numerical results is also presented.