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APPLICATION OF 2D DIGITAL IMAGE CORRELATION METHOD IN FRACTURE MECHANICS
No full textFracture mechanics, a fundamental field in materials science and engineering, deals with the study of crack initiation, propagation, and fracture resistance of materials. Traditional methods in fracture mechanics analysis often rely on analytical or numerical approaches, which may have limitations in capturing crack behavior under various loading conditions. To overcome these challenges, the 2D Digital Image Correlation (2D-DIC) method, a noncontact, full-field measurement technique, is employed to precisely quantify displacement and strain values. This paper investigates the application of the 2D-DIC method in the field of fracture mechanics. Through an experimental investigation that involves fracture toughness testing, crack growth monitoring, and fatigue crack propagation analyses, the effectiveness of 2D-DIC in capturing crack behavior is demonstrated.
The results showcase the method's ability to accurately track crack propagation, providing valuable insight into crack growth mechanisms, and offering new data for understanding fracture mechanics phenomena. This paper contributes to advancing the field by highlighting the utility of 2D-DIC as a powerful tool for studying crack behavior and improving the overall understanding of fracture mechanics
Digital image correlation application to structural integrity assessment
No full textDigital image correlation represents a useful, efficient,
and widely applied method of non-contact strain and displacement measuring in various types of structures. It is often
combined with other means of integrity assessment, such as
the finite element method and the use of fracture mechanics
parameters. This paper presents a short overview of digital
image correlation in various fields including mechanical and
civil engineering, biomedicine, and some other, more ‘exotic’
examples. Additionally, some of the examples shown here
perfectly illustrate the applicability of this method to cases
where high levels of detail and accuracy are necessary in
order to measure strain
Decision Support System for Mining Machinery Risk Mitigation Driven by Ergonomics and Contextual Theory
No full textDespite being very old, the mining industry continues to be one of the major sources
of pollution, with more people killed or injured than in all other industries. Prevention of incidents/
accidents on machinery in mining pits and the issues of operator safety on mining machinery
largely depend on the ergonomic adaptation of the workplace, compliance with safety procedures
and policies, and organizational and other influential factors. Evidently, scarce consideration of those
factors in the available literature has not given satisfactory results till now. The aim of this paper
is to first set up a comprehensive model based on ergonomic factors and contextual theory, which
takes into account all the influencing factors on the occurrence of incidents/accidents and represents
a complex system of interdependence of influential variables of diverse, mostly stochastic nature,
and then design a software solution on the given basis. In this research, based on the extensive data
collected, a model was generated using the structural equations modelling methodology, which was
then used to design the reasoning logic in the expert system for mitigating the risks of the operation
of mining machines. An innovative solution incorporating a mathematical model of the interdependence
of influential variables into the stored knowledge base offers a decision support system that
provides recommendations for the maintenance of a particular mining machine, depending on the
assessment of model factors in a specific decision-making situation at the higher organizational level
and ergonomic suitability for the operator at the lower organizational level, and, in that manner,
enables the mitigating of risky/unwanted events
Finite element analysis of an unconventional hull designed for aquafarming
No full textIn recent years, several designs have emerged for floating vessels intended for aquafarming, where all cargo tanks are located within the hull. These objects are still not addressed in the rules and regulations for ships published by classification societies. In addition, some of the designs significantly differ from conventional ship hulls, implying that such structures need to be checked using direct structural assessments. Therefore, this study presents a finite element analysis of a global model of an unconventional hull designed for aquafarming. Unconventional characteristics of the hull include its large length to height ratio, low length to breadth ratio and large openings spanning from the deck to the inner bottom. Openings serve as cargo tanks for aquafarming. As these features can significantly reduce the strength of the hull, an analysis is performed for several cases, including fully loaded, lightship, and transitory conditions of loaded cargo tanks that the vessel may encounter during its service. The study presents the global response as well as the critical stress zones of the structure, comparing them to the prescribed class-based criteria for standard steel ships. Moreover, in the absence of fully developed rules and regulations, this work provides an overview of the contemporary rules and regulations that can be used in the evaluation of such structures
Inteligentni tehnološki sistemi i procesi - novi pravci razvoja inteligentno-vizuelnog upravljanja mobilnog robota-letelice i optimalno terminiranje tehnoloških procesa u dinamičkim uslovima
No full textAktuelni potprojekat Mašinskog fakulteta u Beogradu, kao i rad na doktorskim disertacijama, podrazumeva novi razvoj inteligentno-vizuelnog upravljanja mobilnog robota-letelice (MBL) specifične namene, kao i optimalno planiranje i terminiranje tehnoloških procesa u dinamičkim uslovima, i to baziranim na tehnikama veštačke inteligencije, posebno na dubokom učenju ojačavanjem i biološki inspirisanim algoritmima optimizacije. Tokom ovogodišnjih intenziviranih naučnih istraživanja razvija se nova metodologija za autonomno kretanje, odnosno navigaciju i inteligentno-vizuelno upravljanje mobilnog robota-letelice sopstvenog razvoja, namenjenog čišćenju staklenih površina visokih zgrada. Takođe, generisanje optimalnog plana terminiranja tehnoloških procesa, u okviru koga se u dinamičkim uslovima rada inteligentnih tehnoloških sistema uzimaju u obzir alternativni izbori resursa poput mašina alatki, alata i pomoćnih pribora, jedan je od važnih ciljeva ovih naprednih istraživanja u domenu daljeg razvoja proizvodnog mašinstva u 21. veku. U ovom radu, dat je pregled nekih od novih pravaca razvoja baziranih na sopstvenim istraživanjima, poput analize algoritama dubokog učenja ojačavanjem koji su od značaja za razvoj inteligentnog upravljanja MBL, prevashodno onih sa kontinualnim prostorom stanja i akcija, kao i analiza primene metaheurističkih algoritama, odnosno evolucionih algoritama, algoritama baziranih na inteligenciji roja i reprezentativnih hibridnih pristupa u okviru terminiranja tehnoloških procesa u dinamičkim uslovima
Modeling Approaches to Shaped Charge Jet Penetration Depth: Numerical and Analytical Perspectives
No full textShaped charge effect have been successfully used in various fields, including defense (anti-armor projectiles and warheads) and non-military (explosive demolitions, oil and natural gas industry) applications. The shaped charge mechanism relies on conversion of explosive charge detonation energy into kinetic energy of a hypervelocity metal penetrator, known as a jet. The focus of the present research is on the jet interaction with the target material and consequent target penetration. Two approaches to the jet penetration depth determination are considered. The first is the well-known analytical model based on the virtual origin concept. The second approach is the numerical modeling of the penetration process. The commercial FEM based software Abaqus/Explicit has been used for simulations and the model formulation is described in detail. The complete process of the shaped charge jet formation and penetration is successfully simulated using the pure Eulerian approach with appropriate material models.
Through comprehensive analysis, various jet parameters – such as kinetic energy, diameter, length, velocity gradient, and effective standoff distance – are explored to assess their impact on penetration depth. The insights gained from this study provide valuable guidance for the preliminary evaluation of shaped charge effectiveness and contribute to the refinement of shaped charge projectile or warhead designs
CHATTER DETECTION USING SUPPORT VECTOR MACHINE
No full textThe paper presents a methodology for chatter detection based on machine
learning. The machining of an internal cone was performed on a CNC lathe, with
several different steps varied during the process. Concurrently with the machining,
acceleration was measured using an accelerometer in the direction of the penetration
force. The acceleration signal showed a sudden change in the form of an increase in
amplitude at the point of chatter occurrence. Using a Support Vector Machine-based
machine learning system, an algorithm was trained to detect chatter based on the
accelerometer signal. The goal of the algorithm is to identify three different states of
the system (stable, unstable – chatter, and transitional regime) on existing signals.
Four signals were used for training the algorithm, while two signals were utilized for
model validation
Digitalization of Strategic Decision-Making in Manufacturing SMEs: A Quantitative SWOT-TOWS Analysis
No full textThe transition of contemporary manufacturing processes from digital to post-digital paradigms within the framework of Industry 5.0 necessitates the integration of both technological advancements and human-centered perspectives. This shift demands a high degree of customization and personalization in production processes, impacting both core and supporting operations. This study investigates the development of a software application designed to facilitate strategic goal-setting in manufacturing Small and Medium-sized Enterprises (SMEs) by leveraging a digitalized Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis. The research focuses on the use of this tool to collect, compare, and rank SWOT factors provided by employees and managers, in order to support data-driven strategic decision-making. The initial phase of the study involved a sample of 520 entrepreneurs and business owners from Poland, Slovakia, the Czech Republic, Hungary, and Serbia, which led to the identification of an extensive list of 83 strengths, 92 weaknesses, 78 opportunities, and 86 threats. These factors were stored in a Google Cloud Database, enabling subsequent comparisons with new data. A further 63 senior decision-makers tested the application by entering their own SWOT factors, comparing them with existing ones in the database, and ranking their significance for strategic planning. The rankings were calculated automatically, with the top-ranked factors forming the basis for further analysis. In the final stage, these rankings were reviewed by five experts from the research consortium, who conducted pairwise comparisons and employed Analytic Hierarchy Process (AHP) analysis to develop a Threats, Opportunities, Weaknesses, and Strengths (TOWS) matrix. This matrix identified potential strategic actions to optimize operations within the investigated region. The findings demonstrate the potential of the software tool to enhance strategic decision-making and improve organizational performance in manufacturing SMEs. The results offer practical insights for decision-makers seeking optimal strategies for operational optimization in their organizations
3D SCANING AND INSPECTION GEOMETRICAL PARAMETERS OF SPROCKET TOOTH PROFILE
No full text3D measurement methods, with a certain accuracy provide a quick response
to the measurement request in almost all stages of the machining process. This paper
presents an application of 3D scanning (GOM ATOS) to inspection the geometrical
parameters of the sprocket tooth profile in the final (post-process machining)
inspection. The scanned sprocket was digitized and analyzed from the standpoint of
specified tolerances and deviations. A method of analyzing 3D scans was developed in
order to define the permissible deviations of the geometric parameters of the sprocket
tooth profile. The result of the conducted research is a new method of determining the
conformity (quality level) of the product (sprocket) by analyzing the deviation of
individual geometric quality parameters (sprocket profile). The deviation analysis
method can serve as a basis for the inspection of other sprocket tooth profiles and
other similar parts
Organizational Resilience Assessment as the Indicator of the Sustainable and Human-centric Industrial Organizations Transformation
No full textIndustry 4.0 brought digitalization to every aspect of the industrial manufacturing processes. Based on the rapid development, besides being accepted as major promoter of the industrial development, Industry 4.0 evoked many controversies, mainly expressed through strong opposition to the related digitalization of the processes, based on the employees’ fear and lack of adequate organizational communication. Based on those circumstances, contemporary manufacturing operations are being transformed from a digital to a post-digital era, in the frame of Industry 5.0 concept. In this concept, post-digital processes are equally concerned with digitalization and with employees’ opinion on their workplace’s conditions and overall business success. In this research, the main focus is placed on the organizational resilience index (RI) assessment in the mining industry organizations, evaluated through the assessment of the employee’s opinion on the most important influencing factors, belonging to the: technical, human, organizational and sustainability, groups. In the assessment, the employees of all organizational levels, including: machinery operators, support workers, operational, middle and top-level managers were included. Methodology for RI calculation included application of MCDA techniques, supplemented by the Fuzzy Logic and additionally boosted by artificial intelligence – through Artificial Neural Networks implementation. Obtained models enable accurate calculation of the organizational RI, and possibility to its prediction, based on the measured influential factors.Plenarni ra