Srđan M Bošnjak

Srđan M Bošnjak
University of Belgrade · Department of Material Handling, Constructions and Logistics

Professor

About

93
Publications
53,242
Reads
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977
Citations
Citations since 2016
32 Research Items
562 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120

Publications

Publications (93)
Conference Paper
Full-text available
This paper presents the results of the study dedicated to the problem of the bucket wheel excavator equalizing system (ES) strength. Finite element analysis of two wheel (TWB), four wheel (FWB) and eight wheel (EWB) bogies were conducted in order to determine weak points in ES structure. Strength and carrying capacity of FWB and EWB structures migh...
Article
Full-text available
Identification of the basic parameters of static stability (BPSS) of the slewing superstructure is the key step in solving the problem of its static stability, as well as static stability of the entire bucket wheel excavator (BWE). Specificity of the slewing superstructure examined in this paper lies in the kinematic breakdown system (KBS) which pr...
Conference Paper
A slewing superstructure (SS) represents a key functional subsystem of bucket wheel excavators (BWEs). Identification of its basic parameters of static stability (BPSS: weight and position of the center of gravity) is of equally crucial significance in design of a BWE and in its exploitation. The BPSS dominantly determine the static stability of a...
Conference Paper
A slewing superstructure (SS) represents a key functional subsystem of bucket wheel excavators (BWEs). Identification of its basic parameters of static stability (BPSS: weight and position of the center of gravity) is of equally crucial significance in design of a BWE and in its exploitation. The BPSS dominantly determine the static stability of a...
Conference Paper
Full-text available
A slewing superstructure (SS) represents a key functional subsystem of bucket wheel excavators (BWEs). Identification of its basic parameters of static stability (BPSS: weight and position of the center of gravity) is of equally crucial significance in design of a BWE and in its exploitation. The BPSS dominantly determine the static stability of a...
Article
An original method for validation of the number of buckets on the working device of a bucket wheel excavator based on the dynamic response of its slewing superstructure (SS) is presented. A set of 16 seemingly acceptable solutions which satisfied the rigid design restrictions, based on the preservation of the existing (a) bucket wheel drivetrain, (...
Article
Tie-rods of the bucket wheel and counterweight booms are vital parts of the bucket wheel excavator slewing superstructure. This paper is dedicated to the problem of identifying the stress state of the critical cross-section ('net section') of the eye plates on these tie-rods. It presents the results of the experimental and numerical investigations...
Article
This paper contains results of tests performed in order to determine mechanical properties of steel P460NL1, used as filler material during the execution of welded joints. Arc welding of samples from which the specimens were taken was carried out through the application of welding process 111, because it is one of the processes for the execution of...
Article
Surface mining systems (SMSs) are among the most significant 20th century achievements in mining industry, whose significance to miners is comparable to the invention of dynamite in the 19th century. However, problems of SMS risk assessment are very scarce in relevant literature. For this reason, this paper aims to establish a consistent risk quant...
Article
Vertical Kaplan turbines, with nominal power of 178 MW and manufactured in Russia, have been installed in 6 hydroelectric generating units of hydro power plant ’Djerdap 1’. Experimental tests were carried out by non-destructive methods in order to determine the turbine condition during the rehabilitation of the hydro power plant. Lack of root penet...
Chapter
A holistic approach to analyzing the dynamic behaviour of a bucket wheel excavator (BWE) superstructure, which is practically neglected by technical regulations but nowadays widely used during their design and redesign, is presented in the paper. The procedure for determining the potential and kinetic energy and the vector of generalized non-potent...
Article
Technical diagnostics of hydromechanical equipment, is based on testing procedures including the history of the exploitation with expert knowledge of structures and operating conditions, as well as, on the analysis of results performed by experts with appropriate experience and knowledge in design, exploitation, maintenance, reliability, fracture m...
Article
Full-text available
The complexity of the slewing superstructure (SS) balancing problem derives from the changeability of its geometric configuration, the complexity of working conditions as well as multiple limitations of the possible set of solutions. Having in mind the fact that the existing reference literature does not fully specify the procedure of static stabil...
Article
Full-text available
A cradle-to-gate LCA analysis of a small belt conveyor was conducted. Manufacturing stage was analysed from the aspects of environmental impacts and energy consumption. The biggest environmental impact in majority of baseline impact categories is obtained from low-alloyed steel production and electricity consumption during the manufacturing stage,...
Article
Sensitivity analysis of the dynamic response of both the designed and the actual models of a slewing superstructure with two masts to the variation of the counterweight mass and the degree of accuracy of the approximation polynomials of the digging resistance was conducted in the paper. Spatial reduced dynamic models of the bucket wheel excavator S...
Article
Buckets are a vital substructure of all digging machines, and are intended for the realisation of the fundamental machine function - soil excavation. This paper presents the results of the experimental-numerical investigation of the cause of the bucket wheel excavator SRs 470 buckets failure. The chemical composition and mechanical properties, the...
Article
Full-text available
Wide flange I-beams with parallel flange contours, which are now predominantly used in production of monorail crane girders, are characterized by a relatively large radial transition between flange contour and rib contour. Therefore, the influence of the radius on the stress state, due to the local bending caused by the action of crane trolley whee...
Article
Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW, have been installed in 6 hydroelectric generating units at hydro power plant Djerdap 1. Hydroelectric generating sets have been designed for the service life of 40 years due to structural solutions and limited possibilities of performing periodic inspections and stat...
Article
Full-text available
Determining a bucket wheel excavator (BWE)’s slewing superstructure weight and its center of gravity (COG) is of extreme importance not only in the design phase, but also after the completion of the erection process and during the operation of the machine. This paper presents a critical comparative analysis of the basic parameters of the static sta...
Article
Full-text available
This paper presents integrity and life estimation of turbine runner cover in a vertical pipe turbines, Kaplan 200 MW nominal output power, produced in Russia, and built in six hydro-generation units of hydroelectric power plant „Đerdap 1” in Serbia. Fatigue and corrosion-fatigue interaction have been taken into account using experimentally obtained...
Article
Full-text available
This paper presents results of experimental examinations of stress concentration influence to fatigue life of butt welded joints with K-groove, produced from the most frequently used structural steel S355J2+N. One group of experiments comprised examinations carried out on the K-groove specimens with stress concentrators of edged notch type. Specime...
Article
This paper presents the results of the pulley fracture analysis. Experimental investigations confirmed that the chemical composition and basic mechanical properties of the pulley material, except the impact energy at a temperature of –20°C, meet the requirements of the corresponding standard. The impact energy value at the temperature of –20°C is f...
Article
Full-text available
This paper presents the results of the pulley fracture analysis. Experimental investigations confirmed that the chemical composition and basic mechanical properties of the pulley material, except the impact energy at a temperature of –20°C, meet the requirements of the corresponding standard. The impact energy value at the temperature of –20°C is f...
Article
Full-text available
The planar response of the bucket wheel excavator superstructure is investigated by using a four degrees-of-freedom discrete dynamic model where truss-like substructures are employed to model the pillar with counterweight arm and bucket wheel boom. Excitation is due to the resistance-to-excavation. Four representative geometric configurations of th...
Article
Full-text available
The results of numerical and experimental researches of local bending problems, carried on classic and medium-wide I profiles, were a basis for the adoption of the current standards (EN 15011: 2014) which regulates the action of the local stress caused by the effect of cart wheels. Regarding the fact that IPB (HE-B) wide flange profiles are largely...
Article
Results of non-destructive testing of the Kaplan turbine runner manhole welded structure are presented, on the basis of which the repair methodology is defined. During repair, the welding technology for elements of the manhole is modified along with the proposal given for the modification of its structural design, because the finite element method...
Article
This paper presents the integrity and reliability evaluation of the heating system as a whole, based on results of metallographic tests performed on parent material and the ultrasonic measurement of wall thickness of elbows made of steel St 35.8.
Article
The influence of constructive parameters on response of bucket wheel excavator superstructure is investigated by using a four degrees-of-freedom discrete dynamic model. Four representative geometric configurations of the superstructure are examined. The maximum displacements and accelerations are observed when the bucket wheel boom is in its lowest...
Article
Full-text available
This paper presents an investigation of the accident which occurred during startup of the extending structure from the transport position. In order to clarify the causes of crack occurrence along almost the entire surface of the lever cross-section, the authors performed visual, experimental (chemical composition, tensile properties, microhardness)...
Article
Full-text available
This paper comments on the recently published work dealing with the problem in the determination of the theoretical output of the bucket wheel excavator. It also includes remarks on the inadequacy in the problem approach and highlights the mistakes in the mathematical model. This work emphasizes the demand for a much wider and deeper approach to th...
Article
A slope failure was the cause of a severe accident of bucket wheel excavator (BWE) Takraf SRs 1200. This paper is dedicated to the engineering challenges that accompanied the process of returning the BWE from its after accident state to the state of full exploitation readiness. After the accident, temporary stabilization of the superstructure was c...
Article
Stable supply tank, with volume V = 250 m³ and operating pressure p = 1,5 MPa, of generation unit 6 at thermal power plant 'Nikola Tesla A' in Obrenovac, is designed for water-steam working fluid. It was made of steel Č 1204 as a single-part welded structure with a single wall. Cylindrical tank shell consists of 8 segments, while torispherical deep...
Article
Normal 0 false false false MicrosoftInternetExplorer4 Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW, have been installed in 6 hydroelectric generating units at ’Djerdap 1’. During the refurbishment of hydropower plant experimental non-destructive tests were performed in order to determine the state of turbine com...
Article
This paper discusses a combined finite element and analytical method for obtaining transverse and longitudinal vibrations of a gantry crane system subjected to an elastically suspended moving body. The two-dimensional inertial effects of the moving body are included in derivation of differential equation of motion for the system. Factors as speed,...
Data
a b s t r a c t The high mobility of open pit machines in heavy duty conditions provides fertile ground for the occurrence of various failures of the traveling mechanisms' vital parts such as chain links. The goal of the study presented in this paper was to diagnose the cause of the damage of the bucket wheel excavator crawler chain links. In order...
Article
The traveling mechanism of the C-700S bucket wheel excavator is of the two-crawler type. Rigid connections between the undercarriage and the crawler beams offer a very high factor of safety against tipping but at the same time create unfavorable conditions for ground surface adaptation. Connections between the crawler beams and the undercarriage cy...
Article
Full-text available
This paper presents the results of the study dedicated to the problem of the bucket wheel excavator two-wheel bogie (TWB) strength. Two variants of the TWB structure were analysed: the originally designed and the redesigned. Three calculation models for stress state identification were used for each of the variants. The first does not iclude the in...
Article
In order to reduce the testing costs for structural welded joints and production losses due to excavator standstill, a new method for integrity and reliability assessment of welded joints during exploitation of bucket wheel excavators has been developed. In this paper, a part of non-destructive testing results for the butt welded joints on bucket w...
Article
The supporting truss of the counterweight boom is a vital part of the bucket chain excavator’s (BCE) superstructure. The occurrence and propagation of cracks in the supporting truss columns’ heads may lead to BCE collapse. The goals of the study presented in this paper were to: (a) diagnose the cause of cracks occurrence; (b) define the reconstruct...
Article
During the refurbishment of the hydroelectric generating set A6 on HPP Djerdap 1, for the state analysis and assessment of the level and causes of degradation of the structure of the vertical Kaplan turbine runner guide vane apparatus non-destructive tests and inspections, as well as destructive tests of base material and welded joints, have been c...
Article
Full-text available
The moving load problem is one of the fundamental problems in structural dynamics. A lot of work has been reported during more than a century ago dealing with the dynamic response of structures at first in the field of transportation such as railway bridges, later on highway bridges and finally various constructions such as are cranes, under the in...
Article
Failures caused by heavy duty conditions, as well as the changes of technological requirements, are basic reasons for the redesign of specific substructures of the high performance machines (HPM). This paper presents solutions of reconstruction and comparative stress analyses for original and redesigned representative HPM subsystems. The efficiency...
Article
The modern design methods lead to the objectivisation of the process of thinking, which is important for the new system development. The aim of objectivisation and decomposition of the design is obvious: it should enable a new approach in the problem solving and thinking of the designer, enriches the large quantity of new information, facts and ide...
Article
The superstructure of the ARs 2000 spreader leans on three crawlers of identical length, width and height. Serious damage to the track wheels threads occurred already during the spreader’s travel from the erection site to the open pit mine as well as immediately after the overburden system exploitation started. The goal of the study presented in th...
Article
Full-text available
This paper deals with eco issues in bulk materials handling in ports. Solid, free-flowing materials are said to be in bulk. Bulk materials handling is very difficult, because it incorporates all the features of liquids, gasses and mass solids. Energy efficiency, dust emissions in nearby environment, dust explosions, jamming, noise, handling of haza...
Article
Full-text available
As it is widely known, there are three basic reasons for the bucket wheel excavators subsystems redesign: (1) better customization of the machine versus operating conditions; (2) easier maintenance and (3) failure of the substructure under consideration. The improved design solution of the excavating device, outlined in this paper, was developed to...
Article
Full-text available
Stacker ARs 2000 presents the final link in the system for continuous overburden removal in the open pit mine “Kostolac” – Serbia. Its superstructure leans on three crawlers of the same length, width and height. During the stacker's travel from the erection site to the open pit mine, three crawler chain links fractured, presenting an indication of...
Article
Full-text available
Failures of the cranes' structural parts unavoidably lead to serious damages or total collapses; these accidents are often followed by very high financial losses and possibly serious injuries or crane-related fatalities. The objective of this research was to identify the causes that led to the failure of the hammerhead tower crane (x1425C) counteij...
Article
This paper comments on the recently published work dealing with the problem in the design of the backhoe excavator working device. It also includes remarks on the inadequacy in the problem approach to the device weight optimization and synthesis, and highlights mistakes in the mathematical model. This work points out the demand for a much wider app...
Article
This paper analyzes failure causes of the combat jet aircraft rudder shaft (RS) which occurred during the flight mission. A finite element method (FEM), utilized to determine the stress state of the RS subjected to hinge moment ultimate load, resulted in the high stress concentration sites around the rivet holes. The longitudinal crack was initiate...
Article
Full-text available
This paper discusses the problems of identifying external loads of multibucket machines for mechanization. External loads are dominantly dynamic with distinguished stochasticity in certain cases. The paper presents the procedures for determining external loads caused by resistance-to-excavation (for bucket wheel excavators) or grabbing soil (for br...
Article
Full-text available
Failures caused by heavy duty conditions, as well as the changes of technological requirements, are basic reasons for the redesign of specific substructures of the bucket wheel excavators (BWE). The efficient redesign should be based on subtle external load identification and sufficient accuracy of stress – strain states determination. This paper g...
Article
The slewing platform is the fundamental part of the bucket wheel excavator (BWE) structure. The occurrence and propagation of cracks in the zones of the slewing platform mantle holes, may probably lead to BWE collapse. The goals of the study presented in the paper were to: (1) Diagnose the cause of cracks occurrence; (2) Define the reconstruction d...
Article
Cracks in the welded joints on the bucket wheel (BW) body of the bucket wheel excavator (BWE) SRs 1300 were discovered after merely 1800h of operation. Investigations are carried out in order to detect the causes of cracks occurrence and thus prevent possible heavy damages to the machine.Working stresses in the BW body are defined by using FEM. Met...
Article
The bucket wheel boom tie-rods are vital structural parts of the bucket wheel excavators (BWE). Their failures inevitably cause BWE collapse and are followed, among other things, by a substantial financial loss (millions of €). Non-destructive testing revealed a flaw in the butt welded joint of the body and eye-plate of the bucket wheel tie-rod. It...
Article
The paper deals with the analysis of moving trolley effects on the dynamic behavior of flexible structure of a mega high-performance quayside container crane (QCC) boom. The boom is modeled as a system with distributed parameters, comprising reduced stiffnesses and lumped masses from other parts of the upper structure. This paper looks both at the...
Article
Full-text available
The dynamics of an overhead crane system with the suspended payload on the trolley moving at a specified constant speed is considered in this paper. The beam is discretizied by 10 elements, while the trolley is modeled as particle along with payload suspended with rope system modeled as spring. The overall mass, damping and stiffness matrix is calc...
Article
This paper gives an analysis of dynamic behaviour of the waterside boom, previously identified as the most important structural part of the mega quayside container cranes (QCC) under moving concentrated mass. The non-dimensional mathematical model used in this paper presents a conceptual substitution of the real system of the mega container crane b...
Article
This paper discusses the cause of the failure in the vital part of the crawler travel gear of the bucket wheel excavator (BWE) – two-wheel bogie (TWB). The results of the finite element analysis (FEA) point out that the main reason of the TWB failure is its insufficient strength under lateral forces acting during curve travel. The weak points in th...
Article
This article deals with the analysis of trolley impact on the dynamic behaviour of the flexible structure of the mega quayside container crane (QCC) boom, identified as the most relevant structural part. It develops a modelling method for the dynamic response of the large flexible structure of the QCC boom under a moving trolley. By using FEM the o...
Article
This paper describes the failure analysis results of the bucket wheel excavator (BWE) portal tie-rod support. The results of finite elements analysis (FEA) point out the occurrence of pronounced stress concentration, whereby multiple stresses in the failure zone exceed the yield stress of the basic material. Experimental investigation on fracture s...
Article
Full-text available
This paper deals with the possibility of aerodynamic instability occurrence in the mobile elevating work platform (MEWP) structure. The vibrations of the structure excited by the von Ka´rma´n street and the movement induced vibrations (galloping phenomenon) are being analyzed. Based on the results obtained by calculations on the model of the real M...
Article
This paper comments on the recently published work dealing with the problem of modeling system dynamics of a slewing flexible beam with moving payload. It also includes remarks on the inadequacy in system modeling and highlights mistakes in the mathematical model. This work points out the practical aspects of tower crane modeling and offers suggest...
Article
A residual strength degradation model for two orientations of fibers of carbon-epoxy composite is proposed. The model is constructed on the basis of an analysis of a gradual decrease in the residual strength of the composite and an increase in loading cycles. Two groups of specimens were subjected to tensile tests under static and dynamic loading....