Nenad Zrnic

Nenad Zrnic
University of Belgrade · Faculty of Mechanical Engineering

Professor Dr.

About

105
Publications
73,530
Reads
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1,073
Citations
Citations since 2016
36 Research Items
658 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Additional affiliations
January 1993 - present
University of Belgrade
Position
  • Vice Dean for International Cooperation

Publications

Publications (105)
Chapter
The paper discusses the history of belt conveyors over the years until the development of the modern belt conveyor at the end of the 19th century. The roots of conveyor systems and principles of operation go back to the ancient times, with a first trace of primitive belt conveyor found in the beginning of the 17th century. The early belt conveyors...
Article
The analysis of behaviour of extended one-sided stiffened bolted end-plate moment connection is revisited here. On the basis of experimental tests, the behaviour of beam-to-column joint with and without stiffener is investigated. The stress distribution and deformation characteristics were determined and discussed with corresponding results of fini...
Conference Paper
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Seaside link operations modelling at Seaport Automobile Terminal (SAT) is considering as a suitable s D M g X / / 1 / /   queue with batch arrivals. This model is very appropriate for a SAT with the automobiles arriving in batches in a ship ramp. It proposes explicit expressions to calculate the SAT performance measures. Related numerical and gra...
Conference Paper
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The paper deals with the mathematical modelling of the dynamic behaviour of the structure of the ship unloader. It is given the procedure for formulation of the reduced dynamic model which retains the main aspects of the behaviour of the structure and yet is simple enough to be performed with standard engineering tools. The approach is applied on t...
Conference Paper
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This paper presents the research, development and application of Industry 4.0 in Intralogistics in the last five years. The progress made in Intralogistics, using Industry 4.0, is presented. An overview of the basic principles and elements of Industry 4.0 as well as its impact in the field of Intralogistics is given. Intralogistics is a field that...
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...
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The aim of this research is to study the dynamic behaviour of a real gantry crane subjected to the actions induced by the trolley and payload movement. A specific numerical procedure was developed and implemented in the finite element method in order to simulate different trolley movement modes on the crane's main beam. From the results, it is clea...
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Treća misija Vojske Srbije predstavlja podršku civilnim vlastima u suprotstavljanju nevojnim pretnjama bezbednosti. Za vreme katastrofalnih poplava maja meseca 2014. godine, pravovremenom i potpunom podrškom civilnim vlastima Vojska Srbije je odigrala jednu od bitnih uloga u spasavanju života i obezbeđenju elementarnih uslova za život ljudi na ugro...
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A new optimization model of Automated Storage and Retrieval Systems (AS/RS) containing three objective and four constraint functions is presented in this paper. Majority of the researchers and publications in material handling field had performed optimization of different decision variables, but with single objective function only. Most common func...
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...
Conference Paper
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The total daily cost of a port queueing system with certain number of berths (servers) is defined as a sum of total service cost per day, total ship cost per day and total marginal cost per day. Then the related specific cost ratio is defined as a ratio of total daily cost of a port queueing system and average daily cost of a ship in port. Using th...
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The last decade brought the blooming of the shuttle-based automated storage and retrieval system (SBS/RS) in many industrial applications. They proved the superiority over the mini-load automated storage and retrieval system mainly due to higher throughput capacity, high flexibility of future extension, much better energy efficiency resulting from...
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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,...
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The notion of specific cost ratio involves different type of costs of a ship and a port modeled as a queueing system. Using the known general formula for the specific cost ratio of arbitrary port queueing system (denoted as R ), here we derive the related expression for R of the M/Ek/1 queue, where Ek ( k = 2,3,...) is the Erlang- k probability dis...
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In this paper we consider batch arrivals of containers at a port container yard which is modeled as a multi-server queue MX/M/c with c yard cranes for the service. It is assumed that the related group size (the number of containers in an arriving group), X is distributed by a Poisson-like distribution. Using a more general formula for such queue mo...
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The main object of this paper is to design a very big derrick crane (the main boom is 80 m in length and the payload is 60 t) considering the dynamical effects induced by moving a load. The research was developed through analytical calculation models for the preliminary design of the crane; subsequently many different finite element model analyses...
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A multi-objective optimization of automated warehouses is discussed andevaluated in the present paper. Since most of the researchers in materialhandling community had performed optimization of decision variables withsingle objective function only (usually named with minimum travel time,maximum throughput capacity, minimum cost, maximum energy effic...
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The article describes a proactive approach to smart maintenance and smart logistics. It presents the areas through which all companies must pass. For its successful implementation it is necessary to introduce appropriate management practices also into the area of maintenance. Irrespective of the level of maintenance work in a particular organizatio...
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Container transport represents a key component of intermodal transport and a substantial contribution to the rapidly growing international trade. The container trade should be optimal to provide a suitable resource utilisation and profitability to key operators, providing them an easy and relatively cheap access to international markets. Numerous a...
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To support an increase in transport flows on Central European inland waterways and contribute to a significant modal shift, shipping companies and owner operators have to be enabled to improve their economic position. One of the ways for achieving this is to develop an innovative inland container vessel and logistics system that allows to meet the...
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This paper describe concept of intelligent logistic for automotive industry created with value stream mapping. Automotive industry has been facing big impact of economic crisis in last years. European Commission prepared initiative to improve use of technology in automotive industry called Factories of the Future. This concept is using fourteen int...
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The container revolution has resulted in major changes in international trade and it is the one of the most important contributions to the globalization of the world economy. In addition to an increased coordination and cooperation between different forms of transport, containerization offers benefits in form of direct effects on cost-reduction and...
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The target of this numerical study is to investigate the problems involved in the design of a low profile container crane exposed both to static and dynamic wind actions, in order to establish if these loads are dangerous when compared with the load induced by standard container load and unload operations. In the first step the work was performed b...
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Intermodal freight transportation refers to a multi-modal chain of container-transportation services which usually links the initial shipper to the final consignee of the container (door-to-door service) and takes place over long distances. Container transportation is a major component of intermodal transportation and international commerce. Contai...
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Light chariots with spoked wheels were developed initially in Syria or Northern Mesopotamia at about the beginning of the 2nd millennium B.C. and quickly propagated all over Middle East. The two-wheeled horsedrawn chariot was one of the most important inventions in history. It gave humanity its first concept of personal transport, and for two thous...
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Liner shipping is the most efficient mode of transport for goods. International liner shipping is a sophisticated network of regularly scheduled services that transports goods from anywhere in the world to anywhere in the world at low cost and with greater energy efficiency than any other form of international transportation. Liner shipping connect...
Conference Paper
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Intermodal transportation, with the options of integrating multiple modes, provides a flexible response to the changing supply chain management requirements in global markets and distribution systems. The container has substantially contributed to the adoption and diffusion of intermodal transportation, which has led to profound changes in the t...
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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...
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The incitation for this paper is the necessity to research the trends in sustainability regarding the mitigation of environmental impacts of logistics equipment in container ports. This paper discusses environmental impacts of the most common type of cargo handling equipment used at container terminals which are yard trucks, by using the methodolog...
Conference Paper
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This paper deals with the simplified life cycle assessment (LCA) of a bucket wheel excavator (BWE) conveyor belting. Belting is the most important component of a belt conveyor. Simplified LCA was conducted with the Ecodesign Assistant (EA) and the Ecodesign PILOT (EP) software tools. Conveyor belting was recognised as ABE hybrid type product, wh...
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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,...
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This paper analyzes the supply chain network with primary focus on import of containers from Far East to Serbia through selected Mediterranean ports (Koper, Rijeka, Bar, Thessaloniki and Constanza). An optimization mathematical model, which minimize time and costs of container imports to Serbia, by using different liner shipping services on the sea...
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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...
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Original scientific paper Conveyors are machines which typically operate continuously during long periods of time. Even a small increase in energy efficiency leads toward considerable energy savings and therefore improved sustainability. The energy is consumed to overcome dissipative effects and for possible lifting of transported goods. It can be...
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In this paper we establish an analytic method for determining the optimal number of berths in a port with finite waiting areas modelled by M/M/n(b)/k queue in the sense of minimization of the related specific cost ratio. Using the general formula for specific cost ratio, we derive a related expression of the M/M/n(b)/k queue. In particular, we pres...
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With the efficient influence on making an adequate and prompt managing decision it is possible to improve operation of any system. This study presents one of the possible ways of exerting influence on the information and material flow so that the management could make optimal decisions in the system of parts regeneration which exists in a multileve...
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The goal of this paper is to present and evaluate the latest trends in the cargo handling equipment (CHE) industry, aimed at mitigating the environmental impact of container terminal operations and contributing to the sustainability of ports. The most common machines for handling containers are described and dealt with separately, with a focus on e...
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The paper deals with the moving load problems within the structural dynamic analysis of a large gantry crane as high-performance machine. The emphasis is placed on combined method approach, i.e. finite element method and analytical postulations, to obtain the mathematical model of crane. Moving trolley is considered throughout several models: movin...
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Performance of containers' flow at yard represents very important point of container terminals. The organization of container transport and stacking policies leads to less congestion and lower costs. Otherwise, containers wait in queue before they are serviced. This study presents an analytical approach for obtaining the average number of container...
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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...
Conference Paper
Full-text available
The total daily cost of a port queueing system consists of the cost related to berths and the cost related to the ships. Then the specific cost ratio is defined as a ratio of total daily cost of a port queueing system and average daily cost of a ship in port. In several port systems it is of interest to minimize the specific cost ratio. Using the k...
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...
Conference Paper
Full-text available
The specific cost ratio (b n R) is defined as a ratio of total daily cost of a port queuing system and average daily cost of a ship in port. In particular, using the obtained formulae for b n R with certain number of berths (b n), we derive the explicit expressions for mentioned costs related to the b n M M / / queue. In addition, we present numeri...
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This work examines the dynamics of a two-dimensional jib crane structure subjected to a moving trolley with hoist and payload. Dynamic responses of the structure, both in the vertical (Y) and horizontal direction (X), are calculated using the finite element method and the direct integration method. Instead of the conventional moving force problem,...
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We discuss dynamic system performance evaluation in the river port utilizing queuing models with batch arrivals. The general models of the system are developed. This system is modelled by M X / M / n / m queue with finite waiting areas and identical and independent cargo-handling capacities. The models are considered with whole and part batch accep...
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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...
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This paper gives ship traffic modeling and performance evaluation in container port. The basic approach used analytical and simulation mod-els. These models are developed for impact analysis of the ship traffic and patterns of arrival ships at terminal performance. Results from both models are compared with each other. Both the simulation and analy...
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The main purposes of the paper are to describe port performance evaluation by queuing models (QMs) based on the nature and applications of the models, state of the art survey based on the classification and identify considered problems and the applications of the existing QMs. There are number of benefits to be gained from QMs for port performance...
Chapter
The history of ropeways is directly related to the development and manufacturing of ropes and cables. Therefore the invention of the steel cable in 1834 by Albert increased the speed of the further development of new ropeway systems. Initially the development was focused on ropeways for transportation of goods, later interest turned to ropeways for...
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After briefly reviewing the history of intralogistics, this paper examines the outlook for the technologies concerned. This is related to the so-called megatrends, such as globalisation, urbanisation, demographic shifts and climate change, which are expected to bring about major global transformations over the next few decades, and which are also l...
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Nikola Tesla (1856-1943) made numerous inventions and discoveries in the field of electricity that form the basis of new scientific and technological breakthroughs, started in the late 19th century, without which our present life could not be imagined. Tesla’s abundant and interesting creative activity in the field of mechanical engineering has onl...
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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...
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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...
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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...
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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...