Digital library of University of Maribor
Not a member yet
81039 research outputs found
Sort by
The effect of heat treatment of high-strength steel on dynamic strength of howitzer cannon barrel
No full textV raziskavi smo se osredotočili na analiziranje integritete in dobo trajanja topovske cevi havbice izdelane iz visoko-trdnostnega jekla 35NiCrMoV12-5, ki je podvržen dvema različnima toplotnima obdelavama, ki ju imenujemo A in B. Analiza izhaja iz vidika lomne mehanike, ki v našem primeru temelji predvsem na konceptu odpornostne krivulje na utrujenostno rast razpok. Tekom raziskave smo eskperimentalno ali teoretično določili vplivne parametre, ki zajemajo velikost miktrostrukturnega zrna, velikost vključkov, natezno trdnost, trajno dinamično trdnost, lomno žilavost, prag utrujenostne rasti dolge razpoke, območje rasti kratkih razpok ter parametre rasti razpoke. Trajno dinamično trdnost materiala smo določi eksperimentalno s pomočjo termografske metode, ki bistveno hitrejšo določitev parametra v primerjavi s klasično metodo utrujanja vzorcev. Modeliranje topovske cevi z metodo končnih elementov (MKE) v programu Abaqus/CAE je bilo izvedeno na podlagi predhodno eksperimentalno določenih mehanskih parametrov materiala. MKE model je bil uporabljen za analizo pol-eliptičnih razpok različnih globin in dveh različnih oblik. V okoli razpoke je bila določena vrednost faktorja intenzitete napetosti na podlagi katerega smo lahko določili obdelavo materiala, ki ima boljšo odpornost proti širjenju utrujenostnih razpok. Z metodo R6 smo nato določili diagram ocene odpornosti (FAD), na podlagi katerega smo lahko določili kritične tlake za različne kombinacije globin in oblik razpok. S podatki, pridobljenimi iz diagramov FAD smo definirali eksponentne funkcije, ki določajo vrednost kritične globine razpoke v odvisnosti od uporabljenega tlaka.
Pristop, uporabljen v tej raziskavi, se je izkazal za učinkovitega pri določevanju vpliva teh upoštevanih spremenljivk na določitev vpliva velikosti vključkov na dobo trajanja topovske cevi havbice ter na varne obratovalne pogoje. Z upoštevanjem kreiranega celostnega modela je namreč določeno varno območje uporabe topovske cevi ter končna utrujenostna življenjska doba v nevarnih pogojih, ki jih definira cev z vsebovano razpoko določene dolžine.This study focuses on analyzing the integrity and fatigue life of a barrel manufactured from the 35NiCrMoV12-5 alloy using two different heat treatments (A, B). The analysis utilizes a fracture mechanics approach, primarily based on the concept of a fatigue resistance curve. To conduct the analysis, various essential variables were either experimentally measured or theoretically estimated. These variables include microstructural size, static strength, fracture toughness, fatigue threshold for long crack growth, short crack range, fatigue crack propagation properties, and fatigue limit. The fatigue limits of both materials were determined experimentally through the thermographic method. Finite Element Modelling (FEM) using Abaqus/CAE software was used in combination with experimental results. The FEM model was used to analyze semi-elliptical cracks of different depths and two different shapes. Stress intensity factor distributions along the crack tip were derived, indicating material resistance to crack propagation. The R6 procedure was then applied to assess the failure assessment diagram (FAD), crucial for identifying critical pressures concerning varying crack shapes and depths. Using the data obtained from the FAD diagrams, we were able to define exponential functions that determine the value of the critical crack depth as a function of the applied pressure.
The approach used in this research has proven effective in determining the impact of the considered variables on assessing the influence of inclusion size on the lifetime of the howitzer barrel and its safe operating conditions. By considering the comprehensive model which we defined, the safe region of the barrel is defined, as well as the final fatigue life under hazardous conditions, as determined by a barrel containing a crack of a certain length
Thermo-Mechanical Analysis of the Roll Support
No full textV magistrskem delu analiziramo nosilec za valje, ki je skupaj z valji izpostavljen ciklični toplotni obdelavi. Pri tej temperature močno narastejo, kar povzroča pojav lezenja. Mehanizem lezenja, njegovi vplivi ter uporabljene metode analize so sistematično predstavljeni. Na tej podlagi pripravimo numerični model in izvedemo preračune ključnih parametrov prestopa toplote. Sledi termo-mehanska numerična simulacija obravnavane toplotne obdelave. Na podlagi dobljenih rezultatov ocenimo življenjsko dobo nosilca oziroma določimo število ciklov toplotnih obdelav do porušitve.In this master’s thesis, the analysis of a roller support and the rollers exposed to cyclical heat treatment is analysed. During heat treatment, the temperature rises significantly, causing creep to occur. The creep mechanism, its effects and the applied analysis methods are systematically presented. Based on this, a numerical model is developed, and key heat transfer parameters are calculated. A thermo-mechanical numerical simulation of the considered heat treatment process is then performed. Based on the obtained results, the service life of the support is evaluated – in other words the number of heat treatment cycles to failure is determined
Development of lifepo4 battery for electric golf carts
No full textMagistrsko delo obravnava razvoj litij-železov-fosfatne (LiFePO4) baterije za električna golf vozila, ki zamenjujejo svinčeno-kislinske sisteme. Vključuje tržno analizo največjih proizvajalcev golf vozil in obstoječih litij-ionskih baterij za določitev ključnih tehničnih zahtev napetosti, kapacitete, velikosti ter zaščite. Na podlagi ugotovitev je razvit koncept baterijskega sistema z 51,2 V nominalne napetosti in 100 Ah kapacitete, ki vključuje konstrukcijo ohišja za sestavne dele baterije. Izvedena je stroškovna analiza materialov in sestave, ki omogoča oceno ekonomske upravičenosti projekta. Delo se zaključi s SWOT analizo, ki izpostavi prednosti, slabosti, priložnosti in tveganja uvedbe baterije na trg.The master’s thesis addresses the development of a lithium iron phosphate (LiFePO₄) battery for electric golf vehicles (golf carts) that replace lead–acid systems. It includes a market analysis of the largest golf vehicle manufacturers and existing lithium-ion batteries to determine key technical requirements for voltage, capacity, size, and protection. Based on the findings, a battery system concept with a nominal voltage of 51.2 V and a capacity of 100 Ah is developed, including the design of an enclosure for the battery components. A cost analysis of materials and assembly is carried out to assess the project’s economic viability. The work concludes with a SWOT analysis that highlights the strengths, weaknesses, opportunities, and risks of introducing the battery to the market
Generiranje testnih primerov za testiranje avtomobilskih zahtev z uporabo rag
No full textThe automotive industry is increasingly confronted with challenges in managing complex requirements and test cases arising from the integration of advanced electronic systems, software functionalities, and compliance with international standards. Conventional manual validation of requirements is time-consuming, error-prone, and resource-intensive, underscoring the need for more efficient and reliable approaches. This thesis investigates the automation of test case generation through the application of Retrieval-Augmented Generation (RAG) in combination with Large Language Models (LLMs). A complete RAG workflow was implemented in Python, incorporating LangChain, LangGraph, Ollama, and ChromaDB to facilitate indexing, retrieval, and generation. The system was trained and evaluated on datasets comprising automotive requirements and test cases, with experiments examining embedding quality, retrieval strategies, prompt engineering techniques, and generative model parameters. The results demonstrate that RAG is capable of generating high-quality, contextually relevant test cases on consumer-grade hardware, thereby significantly enhancing efficiency, consistency, and productivity relative to manual methods. Furthermore, the findings suggest that RAG-based systems are best positioned as complementary tools that support, rather than replace, human engineers. This research provides a foundation for future work on hybrid retrieval methods, advanced embedding techniques, and the integration of more powerful LLMs into requirement and test case management processes.V sosobnem času se avtomobilska industrija sooča z naraščajočimi izzivi pri obvladovanju kompleksnih zahtev in testnih primerov, ki izhajajo iz vključevanja naprednih elektronskih sistemov, programske funkcionalnosti ter zahtev mednarodnih standardov. Tradicionalna ročna validacija zahtev je pogosto zamudna, podvržena napakam in zahteva znatne kadrovske ter časovne vire. V okviru magistrske naloge je obravnavana možnost avtomatizacije generiranja testnih primerov z uporabo metodologije Retrieval-Augmented Generation (RAG) v kombinaciji z velikimi jezikovnimi modeli (LLM). V programskem jeziku Python je bil razvit celovit potek RAG, ki vključuje ogrodja LangChain, LangGraph, Ollama in ChromaDB za namene indeksiranja, iskanja in generiranja. Sistem je bil eksperimentalno preizkušen na naborih podatkov, ki zajemajo avtomobilske zahteve in pripadajoče testne primere. Eksperimenti so bili osredotočeni na ocenjevanje kakovosti preslikave besedila v vektorske predstavitve, učinkovitosti različnih strategij iskanja ter vpliva parametrov generativnih modelov na rezultate. Rezultati empirične analize kažejo, da lahko pristop RAG na lokalni potrošniški strojni opremi generira kakovostne in kontekstualno ustrezne testne primere, kar pomembno prispeva k večji učinkovitosti, doslednosti in produktivnosti v primerjavi s tradicionalnimi ročnimi metodami. Ugotovitve nakazujejo, da je uporaba sistemov, temelječih na RAG, smiselna predvsem kot podporno orodje, ki dopolnjuje delo inženirjev, ne pa kot njihova neposredna zamenjava. Predstavljeni rezultati tako predstavljajo osnovo za nadaljnje raziskave na področju hibridnih metod iskanja ter integracije zmogljivejših modelov LLM v proces avtomatizacije validacije zahtev in testnih primerov
Plant extract usage for reducing nh3 formation in chicken farming
No full textNamen diplomskega dela je ugotoviti vpliv rastlinskih ekstraktov Sapotan powder in Yucca biopowder v reji pitovnih piščancev, na proizvodnost, konverzijo krme, indeks notranjih organov in vezavo NH3 v nastilju. Dnevno smo spremljali količine zaužite krme in vode, merili koncentracije plinov z merilcem Dräger in ocenjevali kakovost nastilja. Tedensko smo beležili maso piščancev in jemali vzorce izločkov. Ob zakolu smo pri treh povprečnih petelinih in treh povprečnih jarkicah v posamezni skupini stehtali očiščen trup, njihove notranje organe (srce, jetra, mlinček, ledvico) in izmerili dolžino tankega črevesja, ter dolžino slepih čreves. Ugotovili smo naslednje, da rastlinski ekstrakti statistično značilno ne vplivajo na ekonomsko pomembne parametre med katere spadajo konzumacija, konverzija in klavni izplen (P > 0,05). Rastlinski ekstrakti nimajo statistično značilnega vpliva na vse notranje organe in dolžino črevesja. Njihov vpliv se statistično značilno izraža v masi jeter pri kateri je signifikantna (P ≤ 0,05) razlika med KONTROLO (39,92 g) ter YUCCA (41,25 g) v primerjav s SAPOTAN I (52,08 g). Ter v masi pankreasa, kjer je statistično (P ≤ 0,05) značilna razlika med SAPOTAN I (3,58 g) in SAPOTAN II (4,42 g). Prav tako smo v poskusu ugotovili, da rastlinski ekstrakti vplivajo na zmanjšanje emisije NH3 v reji pitovnih piščancev, ter da so signifikantne razlike med SAPOTAN II (6,32 ppm) ter YUCCA (6,08 ppm) v primerjavi s KONTROLO (9,17 ppm).The purpose of the thesis was to determine the influence of plant extracts Sapotan powder and Yucca biopowder in broiler chicken, namely their influence on production, feed conversion, internal organ index and reduction of NH3 binding in the litter. We monitored the amount of feed and water consumed daily, measuring the gas concentration with a Dräger meter, and monitoring the quality of the bedding. Weekly tasks included weighing the chickens and taking samples of their excretions. The cleaned carcass, their internal organs: heart, liver, pancreas, kidney and measured the length of the small intestine and the length of the caecum of three average roosters and three average hens in each group were weighed at slaughter. We found that plant extracts do not have a statistically significant effect on economically important parameters including consumption, conversion and slaughter yield (P > 0,05). Plant extracts do not have a statistically significant effect on al internal organs and intestinal lenght. Their influence is statistically significant (P ≤ 0,05) in liver mass, where there is a significant difference between CONTROL (39,92 g) and YUCCA (41,25 g) compared to SAPOTAN I (52,08 g). And in pancreas mass, where there is a statistically significant (P ≤ 0,05) difference between SAPOTAN I (3,58 g) and SAPOTAN II (4,42 g). We also found in the experiment that plant extracts affect the reduction of NH3 emissions in broiler chicken farming, here there were significant differences between SAPOTAN II (6,32 ppm) and YUCCA (6,08 ppm) compared to CONTROL (9,17 ppm)
Optimization of airflow in drying cabinet
No full textMagistrska naloga obravnava optimizacijo pretoka zraka v sušilni omari s toplotno črpalko. Glavni problem je neenakomerna porazdelitev zračnega toka po zadnji steni in stropu komore, kar negativno vpliva na učinkovitost in enakomernost sušenja perila. Namen raziskave je bil izboljšati tokovne razmere z nadgradnjo dveh ključnih komponent: ventilatorskega ohišja in zadnje stene, v katere so bili integrirani usmerniki zraka.
Raziskava temelji na kombinaciji eksperimentalnih meritev in numeričnih simulacij (CFD). Eksperimentalno je bil pretok merjen s senzorji AccuTrac, numerične simulacije pa so bile izvedene v programu Ansys Fluent z metodo končnih volumnov in modelom turbulence k-ω SST. Rezultati obeh pristopov so pokazali, da integracija usmernikov zagotavlja bolj enakomerno porazdelitev hitrosti zraka skozi odprtine na zadnji steni in stropu. Doseženo je bilo optimalno razmerje pretoka – približno 66 % skozi zadnjo steno in 34 % skozi strop – kar izboljša kroženje zraka v komori ter poveča učinkovitost in kakovost sušenja.
Delo potrjuje, da kombinacija numeričnega in eksperimentalnega pristopa omogoča učinkovito optimizacijo pretoka zraka v sušilnih napravah. Poleg tega naloga ponuja smernice za nadaljnje raziskave, kot so vključitev toplotnih izmenjevalcev v model, analiza vpliva vlage in akustičnih lastnosti ter preizkus alternativnih oblik odprtin.The master’s thesis addresses the optimization of airflow in a heat pump drying cabinet. The main problem is the non-uniform distribution of airflow along the rear wall and ceiling of the cabinet, which negatively affects the efficiency and uniformity of laundry drying. The aim of the research was to improve flow conditions by upgrading two key components: the fan housing and the rear wall, into which air deflectors were integrated.
The study is based on a combination of experimental measurements and numerical simulations (CFD). Experimentally, airflow was measured with AccuTrac sensors, while numerical simulations were carried out in Ansys Fluent using the finite volume method and the k-ω SST turbulence model. The results of both approaches showed that the integration of deflectors ensures a more uniform distribution of air velocity through the openings on the rear wall and ceiling. An optimal flow ratio was achieved – approximately 66% through the rear wall and 34% through the ceiling – which improves air circulation in the cabinet and increases the efficiency and quality of drying.
The work confirms that the combination of numerical and experimental approaches enables effective airflow optimization in drying cabinet. In addition, the thesis provides guidelines for further research, such as including heat exchangers in the model, analyzing the influence of moisture and acoustic properties, and testing alternative opening geometries
Development of a Simulation Model for Optimization of the Production Process
No full textV magistrski nalogi je bil razvit simulacijski model proizvodnega procesa z uporabo programske opreme Simio, katerega namen je bil identifikacija in odprava ozkih grl v proizvodnji. Model temelji na realnem proizvodnem planu, ki je zajemal 50.548 delovnih nalogov in je bil uspešno verificiran ter validiran. Na podlagi analize simulacijskih rezultatov so bila identificirana kritična delovna mesta z najvišjo zasedenostjo, kar je omogočilo oblikovanje štirih scenarijev za razbremenitev ozkih grl.
Rezultati analize so pokazali, da je Scenarij 3 najbolj optimalna rešitev, saj omogoča učinkovito razporeditev kapacitet brez potrebe po visokih investicijskih stroških. Izbor optimalnega scenarija je bil dodatno potrjen z uporabo metode analitičnega hierarhičnega procesa (AHP), katerega smo izvedli s štirimi določenimi kriteriji. Vsi zastavljeni cilji in hipoteze so bili potrjeni, naloga pa odpira možnosti za nadaljnje raziskave, zlasti na področju stroškovne analize in dolgoročne kapacitetne strategije.In this master\u27s thesis, a simulation model of the production process was developed using Simio software, with the aim of identifying and eliminating bottlenecks in manufacturing. The model is based on a real production plan comprising 50.548 work orders and was successfully verified and validated. Though analysis of the simulation results, critical workstations with the highest utilization were identified which enabled the creation of four scenarios to relieve bottlenecks.
The analysis results showed that Scenario 3 is the most optimal solution, as it allows for efficient capacity allocation without the need for significant investments costs. The selection of the optimal scenario was further confirmed using the Analytic Hierarchy Process (AHP), which was conducted based on four defined criteria. All stated objectives and hypotheses were confirmed, and the thesis opens opportunities for further research, particularly in the areas of cost analysis and long-term strategy
Optimization of workflows at ELEA iC
No full textZaključno delo obravnava optimizacijo delovnih tokov v podjetju Elea iC, kjer se projektanti pogosto soočajo s časovno potratnimi in ponavljajočimi se nalogami, ki niso neposredno povezane s končnim izdelkom projekta, a so kljub temu nujne za njegovo izvedbo. Te naloge vključujejo primerjavo različic načrtov, digitalizacijo arhivskih zapisov, preverjanje sprememb v projektni dokumentaciji in iskanje podatkov v notranjih bazah. Glavni cilj dela je preučiti možnosti avtomatizacije teh procesov ter raziskati, kako lahko umetna inteligenca in sodobna digitalna orodja prispevajo k večji učinkovitosti in zmanjšanju obremenitve zaposlenih.
Pri raziskavi so uporabljene metode analize obstoječih delovnih procesov in testiranja digitalnih rešitev, ki omogočajo avtomatizacijo ponavljajočih se nalog. Poseben poudarek je na implementaciji programskih skript v jeziku Python za avtomatizacijo procesiranja podatkov, uporabi SQL podatkovnih baz za učinkovitejše upravljanje podatkov ter integraciji orodij, kot sta PyCharm in pgAdmin. Umetna inteligenca se v delu uporablja za preverjanje načrtov, brskanje po internih bazah znanja in izboljšanje dostopa do informacij.
Rezultati dela kažejo, da je z ustreznimi tehnološkimi rešitvami mogoče znatno skrajšati čas, potreben za izvedbo podpornih nalog, zmanjšati napake pri obdelavi podatkov ter izboljšati preglednost in dostopnost dokumentacije. Optimizacija delovnih procesov z avtomatizacijo prispeva k večji produktivnosti zaposlenih in omogoča projektantom, da se osredotočijo na ključne faze projektiranja, ne pa na administrativna opravila.This master\u27s thesis examines the optimization of workflows at Elea iC, where designers often face time-consuming and repetitive tasks that are not directly related to the final project deliverable but are nonetheless essential for its execution. These tasks include comparing different versions of plans, digitizing archival records, verifying changes in project documentation, and searching for data within internal databases. The main objective of the thesis is to explore automation possibilities for these processes and investigate how artificial intelligence and modern digital tools can contribute to increased efficiency and reduced workload for employees.
The research applies methods of analyzing existing workflows and testing digital solutions that enable automation of repetitive tasks. A particular focus is placed on implementing Python scripts to automate data processing, utilizing SQL databases for more efficient data management, and integrating tools such as PyCharm and pgAdmin. Artificial intelligence is applied to verify project plans, search internal knowledge bases, and improve access to information.
The findings demonstrate that appropriate technological solutions can significantly reduce the time required for executing support tasks, minimize errors in data processing, and enhance the transparency and accessibility of documentation. Optimizing workflows through automation contributes to greater productivity among employees and allows designers to focus on key project phases rather than administrative tasks
Implementation of an erp solution in a production company
No full textZaključno delo predstavlja implementacijo ERP-rešitve (poslovno informacijske rešitve) v proizvodnem podjetju. Na podlagi preučenih agilnih metodologij smo oblikovali implementacijski načrt, ki je vseboval ključne cilje, sestavo projektne ekipe, časovnico projekta, analizo obstoječega stanja in poslovnih zahtev. Sledila je analiza vrzeli, kjer smo identificirali razlike med obstoječimi procesi in funkcionalnosti nove ERP-rešitve. Na podlagi ugotovljenih odstopanj smo s konfiguracijo sistema dosegli želeno delovanje. V fazi konfiguracije smo ERP-rešitev integrirali z MES (sistemom za upravljanje proizvodnje). V fazi izvedbe smo poskrbeli za pripravo in migracijo podatkov, dodatno konfiguracijo sistema, izobraževanje uporabnikov ter organizacijo vzporednega delovanja. V obdobju vzporednega delovanja smo izvajali primerjavo rezultatov med staro in novo ERP-rešitvijo. Vzporedni prehod je bil ključna faza, v kateri smo odkrili napake in poskrbeli za njihovo odpravo v sistemu. Po vzporednem prehodu je sledil prehod v živo, kjer je nova ERP-rešitev v celoti nadomestila prejšnji sistem. Analiza izvedbe je pokazala, da nova ERP-rešitev omogoča več funkcionalnosti, povezljivosti z drugimi sistemi ter podporo za kompleksnejše analize in poročanja. Z implementacijo nove ERP-rešitve sta se spremenila tudi podatkovna baza in varnostno kopiranje.The thesis focuses on the implementation of an ERP (enterprise resource planning) solution in a production company. Based on reviewed agile methodologies, we developed the implementation plan, where we defined key goals, the project team, the project timeline, and conducted an analysis of the existing business processes and requirements. This was followed by a gap analysis, where we identified the differences between the existing processes and the functionalities of the new ERP solution. Based on the identified discrepancies, we configured the system to achieve the desired operation. During the configuration phase, we integrated the ERP solution with the MES (manufacturing execution system). In the execution phase, we focused on data preparation and migration, additional system configuration, user training and organizing parallel operations. During the parallel run, we compared the results between the old and new ERP systems. The parallel transition was a crucial phase where, we identified and corrected system errors. After the transition, we moved to the go-live, where the new ERP solution completely replaced the previous one. The performance analysis showed that the new ERP solution offers more functionality, connectivity with other systems, and support for complex analysis and reporting. The implementation of the new ERP solution also led to a change in the database and backup system
Expediency of using uv-c or fan to decrease mold growth in coffee machines
No full textV magistrski nalogi sem raziskoval uporabo UV-C svetlobe in ventilatorja za zmanjševanje rasti plesni v kavnih aparatih podjetja BSH. Plesen je problem zaradi vlažnega okolja in ostankov kave v notranjosti aparatov. Namen naloge je bil razvoj merilnega sistema za spremljanje temperature, vlage in vizualnih sprememb ter hkratno aktivacijo UV-C LED diod in ventilatorja. Rezultati so pokazali, da UV-C uspešno dezinficira površino kavnih ostankov, vendar ne prepreči rasti plesni iz notranjosti, medtem ko ventilator sicer odstranjuje vlago, a ne posuši kavnih ostankov dovolj učinkovito. Zato je potrebna optimizacija obeh pristopov.In this master’s thesis, I investigated the use of UV-C light and a fan to reduce mold growth in coffee machines produced by BSH. Mold development is a common issue due to the humid environment and coffee residues inside the machines. The aim of the work was to develop a measurement system for monitoring temperature, humidity, and visual changes, while also enabling the activation of UV-C LEDs and the fan. The results showed that UV-C effectively disinfects the surface of coffee residues but does not prevent mold from growing inside them, while the fan reduces humidity yet fails to dry the residues sufficiently. Therefore, optimization of both approaches is required