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Environmental and Social Assessment of SHPP Mojanska 3 - Expertise
No full textM103 - The expertise is done for Deloitte Consulting co. The investor was EIB (European Investment Bank)
Data interoperability and digital measurement twins in coordinate metrology
No full textU radu je predstavljeno jedno rešenje problema interoperabilnosti između dva različita DMIS (Dimensional Measuring Interface Standard) koda u kontekstu digitalnih mernih blizanaca (DMB) za Industriju 4.0. U svrhu istraživanja, konfigurisan je merni sistem koji uključuje numerički upravljanu mernu mašinu (NUMM), merni predmet i stezni pribor. DMB obuhvata virtuelne i fizičke komponente, pri čemu je virtuelna komponenta kreirana u CAD okruženju korišćenjem PTC Creo softvera. Krajnji izlaz iz virtuelnog i realnog merenja jesu DMIS datoteke. U radu je sprovedena analiza i poređenje DMIS kodova iz različitih softverskih okruženja (PTC Creo i PC-DMIS) kako bi se identifikovale i prevazišle prepreke interoperabilnosti. Istraživanje naglašava značaj usklađivanja kodova za tačno i efikasno funkcionisanje komunikacionog protokola između virtuelne i fizičke komponente DMB, kao i za poboljšanje simulacije i optimizaciju mernih putanja. Razlike u
strukturi i sintaksi kodova mogu uticati na tačnost merenja i zahtevaju dodatne korake kako bi se osigurala ispravna komunikacija između različitih NUMM. Ovaj rad pruža i pregled procesa inspekcije od modeliranja do stvarnih merenja na NUMM, ističući osnovne razlike između dva DMIS koda. Rezultati ukazuju na informacione praznine i izazove interoperabilnosti, te predlažu načine za njihovo prevazilaženje.The paper presents a solution to the interoperability problem between two different DMIS (Dimensional Measuring Interface Standard) codes in the context of digital measuring twins (DMT) for Industry 4.0. For the purpose of the research, a measuring system based on coordinate measuring machine (CMM), a measuring part and a fixture was configured. DMT includes virtual and physical components, with the virtual component created in a CAD environment
using PTC Creo software. The final output from virtual and real measurements are DMIS files. The paper analyzes and compares DMIS codes from different software environments (PTC Creo and PC-DMIS) in order to identify and overcome interoperability barriers. The research emphasizes the importance of code alignment for the accuracy and efficient functioning of the communication protocol between the virtual and physical components of the DMT, as well as for the improvement of simulation and optimization of measurement paths. Differences in code structure and syntax can affect to the measurement accuracy and require additional steps to ensure proper communication between different CMMs. This paper also provides an overview of the inspection process from modeling to real measurements on CMM, highlighting the basic differences between the two DMIS codes. The results indicate information gaps and interoperability challenges, and suggest ways to overcome them.Za izdavača: Dekan, dr Vladimir Popović, red. prof.
Tehnički urednici:
Prof. dr Saša Živanović, Doc. dr Miloš Pjević, Doc. dr Dušan Nedeljković, Lazar Matijašević, mast. inž. maš.
Štampa: Planeta print
Advancing CFD validation methods for self-propelled inland waterway vessels a workshop initiative
No full textThis paper represents a workshop about developing
methodologies for validating computational fluid dynamics (CFD)
simulations concerning full-scale self-propelled inland waterway vessels.
Given the absence of previous workshops addressing this vessel category, the
primary objective is to establish validation methods through the acquisition
of self-propulsion speed and power measurements. Methodological
consistency is paramount, emphasizing the creation of comprehensive 3D
models covering vessel hull, appendages, superstructures, and propulsion
components using original ship documentation and 3D scanning technology
where necessary. Result presentation encompasses various hydrodynamic
parameters, including resistance forces, thrust, wake fraction, thrust
deduction factor, propeller performance, delivered power, shaft speed and
vessel speed evaluated under calm water and self-propulsion conditions.
Companies and institutions will be invited to join the workshop, where
participants will validate their CFD methodologies using standardized
models and analyze grid uncertainties across computational densities. The
workshop aims to establish a validation framework for CFD simulations in
inland waterway cargo vessels, with future plans for extending validation to
shallow water river trials. Collaboration and transparency are emphasized,
with respect for participants' preferences regarding result disclosure
Tensile properties of pure PLA polymer dedicated for additive manufacturing
No full textThis research aims to provide comprehensive data on PLA polymer tensile properties via conducted tensile tests on 100 % infill density specimens (for 0.3; 0.2; 0.1 mm layer height), and all possible lower infill results (i.e., from 90 to 10 %, with a 10 % increment) obtained by interpolation of previous research findings. Tensile tests are performed using dedicated ISO 527-2 standard. Next, the FEM analysis is performed for the 100 % case to verify the FEM model. Thus, the implemented constitutive models of this thermoplastic material and FEM simulations match the experimental data
CNC BRUSILICA ZA 3+2 OSNO BRUŠENJE PROFILNIH KOTURASTIH GLODALA SA LEMLJENIM PLOČICAMA OD TVRDOG METALA
No full textOsnovu tehničkog rešenja čini CNC mašina sa tri translatorne pogonske ose i dodatim podeonim
aparatima. Upotrebom podeonih aparata, izbegnuta je upotreba obrtnih osnaženih pogonskih osa te se razvijena CNC mašina po svom konceptu razlikuje od postojećih i komercijalizovanih mašina iste namene. Pogonske ose Z i Y su ose kojima se omogućava kretanje alata (tocila) u dva pravca. Radni sto mašine ima mogućnost kretanja u pravcu ose X. Na radni sto mašine su postavljeni podeoni aparati kojima se obezbeđuje željena orijentacija obratka. Podeonim aparatima se omogućava obrtanje obratka oko ose Y i Z. Po analogiji sa petoosnim CNC mašinama obrtnim kretanjima su dodeljene oznake B i C. Prema datom opisu kinematička struktura razvijene CNC mašine namenjene za izradu profilnih glodala može se opisati strukturnom formulom C’B’X’OZY
Modification and experimental validation of the Forrestal-Warren Perforation Model for high hardness armor steel plates of intermediate thickness
No full textThis paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates. When impacted by armor-piercing projectiles, these plates tend to fail through adiabatic shear plugging which significantly reduces their ballistic resistance. To address this effect, an approach for determining effective thickness was defined and incorporated into the predictive model. Ballistic impact tests were performed to assess the modification’s validity, in which ARMOX 500T steel plates were subjected to perpendicular impacts from 7.62 mm×39 mm steel-cored rounds under various velocities. Frequent target failure by soft plugging was observed, as well as the brittle shatter of the hard steel core. Key properties of the recovered plugs including their mass, length and diameter were measured and reported along with the projectiles' residual velocities. Additionally, independent data from the open literature were included in the analysis for further validation. The original Forrestal-Warren model and the novel effective thickness modification were then used to establish the relationship between impact and residual velocities, as well as to determine the ballistic limit velocity. The comparison revealed that the proposed approach significantly improves the model's accuracy, showing a strong correlation with experimental data and reducing deviations to within a few percent. This enhancement highlights the potential of the effective thickness term, which could also be applied to other predictive models to extend their applicability range. Further exploration into other armor steels and impact conditions is recommended to assess the method's versatility
Design and operational features of an active condensation system for enhanced energy efficiency in a biomass-fired district heating plant
No full textThe study addresses the design and operational features of an active condensation (AC) system
aimed at improving the energy efficiency of a 3rd generation district heating (DH) plant. Several
similar biomass-utilizing plants have recently been built in the Republic of Serbia. The plant is
equipped with biomass-fired boilers totaling 2 MW capacity, utilizing varying qualities of wet
wood chips. The goals are: (i) to determine optimal constant and variable quench temperatures;
(ii) to calculate the electricity consumption of ancillary devices and assess their impact on AC
system performance; (iii) to evaluate the effect of biomass moisture variations on system size and performance; (iv) to assess the economic viability of integrating the AC system; and (v) to
establish selection and design criteria for the heat pump (HP). For a given commercial HP, an
optimal quench temperature exists, dependent on the minimal temperature lift required by the
HP. This temperature can be calculated simply by subtracting the minimal HP lift from the lowest
possible temperature that the HP can supply to a DH system at the average outdoor temperature.
Consequently, an optimal variable quench temperature exists that should be adjusted to enable
the HP to operate with its minimal temperature lift
Corrosion-induced thickness diminution of an ageing bulk carrier
No full textThe 2030 Agenda for Sustainable Development introduced 17 Sustainable Development Goals (SDGs). The International Maritime Organization (IMO) has endorsed connections between the maritime sector and SDGs, emphasising sustainable production in the marine environment. Consequently, technical considerations, such as ship structure sustainability, are crucial for marine safety. The impact of corrosion influences the structural degradation of vessels and the risk of structural failure and fuel oil spills significantly. The formulation of predictive corrosion models, grounded in historical data accumulated during vessel operations, emerges as an optimal strategy for designing structural elements and guaranteeing their structural integrity. This paper analyses non-linear deterministic and stochastic corrosion models, focusing on an ageing bulk carrier, to provide design-phase information for sustainable structures. Utilising data on measured steel plate thickness over a 20-year operational period, nonlinear models are employed to calculate the millimetres of thickness diminution. Assuming corrosion onset at 7, 8, and 9 years, corresponding coefficients are computed, based on the developed model. A model is also considered, in which there were no assumptions about the beginning of corrosion initiation. The corresponding annual corrosion rate was observed separately in each of the models, as a deterministic variable and as a probabilistic random variable. This approach aims to enhance the understanding of the causal relationship between corrosion processes and structural performance, contributing to the development of sustainable design practices in the maritime industry
Biomimicry potential in structural engineering
No full textComposite materials are widely used in modern structural engineering because of their excellent strength-to-weight ratio, but composites are not only related to man-made structures. Biomimicry is a term related to the imitation of natural phenomena in human engineering science. By combining knowledge about composite materials and natural structures, we can gain insight into how to make more resistant structures. The main goal of this paper is to compare lamina models by applying finite element analysis to obtain information about mechanical characteristics. It was shown that nature-inspired structures have the potential for engineering applications. The mechanical characteristics of those structures can be predicted by applying the finite element method. The concept of biomimicry is intriguing because, in nature, many structures can be used as inspiration for new applications in engineering science
INTEGRATION OF LOOP HEAT PIPE ANTI-ICING SYSTEM IN THE AIRFOIL LEADING EDGE
No full textIntegration of heat pipes into the leading edge of airfoils presents a viable option for anti-icing applications, owing to their lightweight, compact design, passive operation, and heat transfer characteristics. Aircraft operation is greatly influenced by ice formation, which can cause aerodynamic performance deterioration and generally present a threat to flight safety. Complex heat transfer processes due to evaporation and freezing of water droplets, sensible heat loss, but also heating due to kinetic energy of water droplets hitting the airfoil and pneumatic heating, variable weather conditions, etc, all make the analytic solution unattainable for prediction
of ice formation. Simulation methods today are affirmed for aircraft’s icing/de-icing system prediction, from small ones – UAVs, over helicopter rotors, to large passenger planes' airfoils. Insights gained from the numerical simulation study can provide valuable guidance for optimising the design and operation of heat pipe based anti-icing and deicing systems in the aerospace industry. One of the primary ways to evaluate the anti-icing effect is to predict the temperature of the wing skin on the outside. Here presented numerical simulation deals with the loop heat pipe integrated into the wing’s leading edge. The volume of fluid method (VOF) was employed for simulating the condensation process inside the loop heat pipe, leading to further investigation of
temperature distribution over the leading edge outer surface. In perspective, results can be the basis for further customised solutions of anti-icing operations for particular aircraft