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Structural Analysis of Additional Frontal Protection (AFP-Halo) for a Racing Car
No full textU završnom radu „Analiza mehaničkog ponašanja AFP-Halo zaštitne konstrukcije motornog
vozila za utrke“ odrađena je simulacija testiranja AFP-Halo zaštite s motornih vozila za utrke otvorenog tipa. Korištena je metoda konačnih elemenata u softveru Simcenter Femap. Rubni uvjeti i opterećenja zadani su prema normi FIA 8869-2018 po kojoj se i provjeravaju dobiveni rezultati analize. Aproksimativno je izrađen model konstrukcije koji se koristi kao polazište za pripremu analize. Analiza je provedena s dva pristupa, sa grednim konačnim elementima i sa pločastim konačnim elementima. U radu je opisana kompletna priprema analize, a to obuhvaća definiranje ponašanja materijala, definiranje značajki konačnih elemenata, omreživanje modela i zadavanje opterećenja i rubnih uvjeta. Obuhvaćene su i postavke koje su ključne u provođenju materijalno nelinearne analize. Na posljetku su prikazani i komentirani rezultati analize.In this final paper titled „Structural Analysis of Additional Frontal Protection (AFP-Halo) for a Racing Car“ a simulation of testing conditions on AFP-Halo protection from open-wheel racing vehicles was done. Finite element method along with software Simcenter Femap was used. Boundary conditions and loads are set as they are defined in FIA 8869-2018 standard through which the results of the analysis are also checked. An aproximate model of the structure was made as a starting point for preparing the analysis. The analysis was conducted using two approaches, beam finite elements and plate finite elements. Complete preparation of the analysis is descrbed in this paper including defining material behaviour, defining finite element properties, meshing the model, setting loads and constraints. The settings vital for conducting materially nonlinear analysis are also covered. At the end, results of the analysis are presented and discussed
Simplex method
No full textOvaj rad predstavlja analizu simpleks metode, temeljnog algoritma u domeni linearng programiranja. U uvodnom dijelu rada, istražuje se povijesni razvoj simpleks metode, naglašavajući njen značaj i doprinos evoluciji ove matematičke discipline. Slijedi detaljno objašnjenje matematičkog okvira problema linearne optimizacije, uključujući definicije funkcija cilja, ograničenja i strukture samog linearnog programa.
Poseban fokus stavljen je na koncept konveksnosti i njegovu ključnu ulogu u primjeni simpleks metode. Definiraju se konveksni skupovi i konveksne funkcije, te se matematički dokazuje konveksnost linearnih funkcija.
Rad postupno otkriva mehanizme simpleks metode, krećući se od grafičke metode, preko ključnih elemenata poput simpleks tablice i tehnike pivotiranja, do rješavanja problema minimizacije. Osim osnovnih principa, obrađuju se i napredne teme poput Charnesove M metode, koja proširuje primjenu simpleks metode na probleme s početnom nedozvoljenom točkom, te analize osjetljivosti, koja omogućuje evaluaciju utjecaja promjena ulaznih parametara na optimalno rješenje.
Konačno, praktična primjena simpleks metode ilustrirana je kroz primjenu na konkretnom inženjerskom problemu, pri čemu je rješavanje provedeno korištenjem Excel Solver-a.This work presents analysis of the simplex method, a fundamental algorithm in the field of linear programming. The introductory part delves into the historical development of the simplex method, emphasizing its significance and contribution to the evolution of this mathematical discipline. A detailed explanation of the mathematical framework of linear optimization problems follows, including definitions of objective functions, constraints, and the structure of linear programs themselves.
Particular attention is given to the concept of convexity and its crucial role in the application of the simplex method. Convex sets and convex functions are defined, and the convexity of linear functions is mathematically proven.
The work gradually unveils the mechanisms of the simplex method, starting from the graphical method, moving through key elements like the simplex tableau and the pivoting technique, and arriving at the solution of minimization problems. Beyond the basic principles, advanced topics are addressed, such as the Charnes M method, which extends the application of the simplex method to problems with an infeasible initial solution, and sensitivity analysis, which allows for the evaluation of the impact of changes in input parameters on the optimal solution.
Finally, the practical relevance of the simplex method is illustrated through its application to a concrete engineering problem, where the solution is obtained using Excel Solver
Visualization and animation of a computer simulation of the spread of forest fires
No full textTema ovoga rada bila je izrada animacije i vizualizacije računalne simulacije širenja šumskog požara. Napravljene su dvije simulacije, jedna na području Podhuma, a druga na području Platka. Prvo je bilo trebalo prikupiti sve potrebne podatke kao što su podaci o: elevaciji, vegetaciji, okolnoj temperaturi itd. Vegetacija se mapirala preko Google mapa, a vrijednosti elevacije su izvučene iz digitalnog modela reljefa. Potom su, koristeći Python skripte, podaci zapisani u datoteke na način koji je razumljiv rješavaču. Rješavač, odnosno program, u kojem su simulacije rađene bio je OpenFOAM, a dobiveni rezultati su onda vizualizirani u Blender-u.The topic of this paper was to make an animation and visualization of a computer simulation of wildfire spread. Two simulations were made, one in the area of Podhum and the other in the area of Platak. First it was needed to collect all the necessary data like the data about: elevation, vegetation, ambient temperature etc. Vegetation was mapped via Google Maps and the elevation values were extracted from the digital elevation model. Then, using Python scripts, the data was written in files in a way that was understandable to the solver. The solver, that is the program, in which the simulations were made was OpenFOAM, and the obtained results were then visualized in Blender
Determination of calorific value of different types of vegetable oils by calorimetry
No full textZavršni rad smo započeli sa objašnjavanjem definicije i klasifikacije biogoriva te njegova primjena. Spomenuta je njegova ekonomska i ekološka potreba te kakav je utjecaj imao kroz povijest. U drugom poglavlju pod nazivom Kalorimetriranje detaljno smo opisati postupak i aparaturu mjerenja promjene temperature vode u kalorimetru pomoću koje smo odredili ogrjevnu vrijednost pojedinog uzorka. Koristili smo se kalorimetrom modela Parr model 1341 Oxygen Bomb Calorimeter koji se nalazi na Tehničkom fakultetu u Rijeci. Odradili smo po jedno mjerenje za svaki zadani uzorak i na kraju usporedili rezultate. Za eksperiment smo uzeli uzorke od suncokretovog, maslinovog, kokosovog i bademovog ulja. Na kraju smo spomenuli energetsku ovisnost o strukturi masti i usporedili bolju energetsku vrijednost zasićenih kiselina od nezasičenih.We began the thesis by explaining the definition and classification of biofuels and their applications. We mentioned their economic and environmental necessity, as well as their historical impact. In the second chapter, titled Calorimetry, we described in detail the procedure and equipment used to measure the temperature change of water in a calorimeter, which allowed us to determine the heating value of individual samples. We used the Parr model 1341 Oxygen Bomb Calorimeter, located at the Faculty of Engineering in Rijeka. We conducted one measurement for each given sample and compared the results at the end. For the experiment, we used samples of sunflower, olive, coconut, and almond oil. Finally, we discussed the energy dependence on fat structure and compared the better energy value of saturated acids to unsaturated ones
Mechanical fixture design for the machining process
No full textCilj rada je bio na temelju raspoloživih 3D standardnih dijelova dostupnih proizvođača napraviti
konstrukciju mehaničke stezne naprave za unaprijed definirani obradak. Prikazan je teorijski
pregled mogućnosti stezanja na temelju podrijetla sile stezanja. Mehanička stezna naprava je
zamišljena tako da sila stezanja je ručna sila operatera na stroju. Provjerena je dostatnost sile
stezanja s obzirom na silu rezanja, te je kontroliran dozvoljeni tlak na obratku. Za izradu
sklopnog i radioničkih nacrta korišten je program Autodesk Inventor Professional 2023.The goal of the work was to build a mechanical clamping device for a predefined workpiece
based on available 3D standard parts from available manufacturers. A theoretical overview of
clamping possibilities based on the origin of the clamping force is presented. The mechanical
clamping device is designed so that the clamping force is the manual force of the operator on the
machine. The sufficiency of the clamping force with regard to the cutting force was checked, and
the permissible pressure on the workpiece was controlled. The Autodesk Inventor Professional
2023 program was used to create assembly and workshop drawings
Decarbonization through hybrid energy systems
No full textDekarbonizacija kroz hibridne energetske sustave jedna je od metoda smanjenja emisije CO2 u svijetu. U ovom se završnom radu obrađuje primjer kućanstva s hibridnim PV-BESS energetskim sustavom koji se sastoji od kućne solarne elektrane, izmjenjivača, baterijskog sustava i mrežnog priključka. Ovaj hibridni energetski sustav se projektira pomoću PV*SOL programskog alata. Rezultati dobiveni simulacijom su analizirani te su se pokazali zadovoljavajućima za provedbu procesa dekarbonizacije energetskog sektora.Decarbonization through hybrid energy systems is one type of carbon emission reduction. This final work analyses the example of a household with a hybrid PV-BESS energy system that is made of home photovoltaic system, inverter, battery energy storage system and grid connection. This system is designed using PV*SOL app. The simulation results were analysed and they showed positive outcomes for decarbonization of the energy sector
Developmet of integrated project and issue management system
No full textOvaj završni rad bavi se razvojem web sustava za vođenje projekata i upravljanje zadacima, s ciljem poboljšanja organizacije, produktivnosti i suradnje u timovima. Sustav je razvijen koristeći moderne tehnologije kao što su C#, ASP.NET Core, React i TypeScript, te pruža korisnicima intuitivno i responzivno korisničko sučelje. Opisane su ključne funkcionalnosti sustava, uključujući prijavu i registraciju korisnika, upravljanje zadacima, prostorima i korisnicima, te sigurnosne mjere poput uporabe Entity Frameworka za upravljanje bazom podataka. Testiranja su pokazala da je sustav stabilan, siguran i učinkovit, te zadovoljava sve zadane ciljeve.This study is focused on the development of a web system for project management and task tracking, with the aim of improving organization, productivity, and collaboration within teams. The system is built using modern technologies such as C#, ASP.NET Core, React, and TypeScript, providing users with an intuitive and responsive user interface. Key functionalities of the system include user registration and login, task, space, and user management, as well as security measures like using Entity Framework for database management. Testing has demonstrated that the system is stable, secure, and efficient, successfully meeting all established goals
Redesign of the BMW 316 clutch
No full textNakon definiranja zadatka projekta, izvodi se demontaža postojeće spojke i njezina analiza. Redizajn se provodi na dva osnovna dijela spojke: na lameli i potisnoj ploči s kućištem čije se konstrukcije proučavaju te se uzimaju njihove izmjere. Nakon utvrđivanja ulaznih podataka (temperatura okoline, radni moment, moment inercije i brzina vrtnje motora te karakteristike sivog lijeva), provode se tri različita proračuna kako bi se utvrdio rad spojke u različitim uvjetima i odredio kritični slučaj. Proračunom se računaju debljina potisna ploče i površina dodira tarnog para preko koje se određuju vanjski i unutarnji promjer tarne plohe lamele. Zatim se izvodi analiza usvojenih vrijednosti kako bi se dobile kritične vrijednosti ulaznih podataka te se utvrđuju njihovi međusobni odnosi. Izrađuje se virtualni model nove spojke na način da se modelira svaka pojedina komponenta koje se spajaju u dva osnovna dijela spojke pomoću sofwtwarea Autodesk Inventor Professional 2022. Svaki element je detaljno opisan te su navedene sve dimenzije i promjene u odnosu na originalni dio u postojećoj spojci. U svrhu modeliranja lamele izrađuju se tarna ploča, lisnata opruga, glavna i sporedna ploča, glavina, cilindrične zavojne opruge i zatici, a za drugu komponentu potisna ploča, tanjurasta opruga, žičani prsten, kućište, lisnata opruga i ponovno zatici. Oba modela se uspoređuju s originalnim te se konačno definira uspješnost cijelog projekta.After defining the goal of the project, the existing clutch is dismantled and analysed. Two elementary parts of the clutch are redesigned: the clutch plate and the pressure plate with the cover, the constructions of which are observed and measured. After determining input data (the temperature of the environment, the operating torque, moment of inertia, and rotation speed of the engine, and the characteristics of gray cast iron), three different calculations are carried out in order to determine if the clutch is going to work in all conditions and to conclude the critical case. The width of the pressure plate and the friction pair surface, from which the outer and inner diameters of the clutch plate's friction surface are determined, are calculated. Upon that, the output data is analysed in order to get critical values of the input data and their relation to one another. A virtual model of the new clutch is made, in such a way that each individual component is modeled and put together to form two main clutch parts with the help of software Autodesk Inventor Professional 2022. Each element is described in detail and their dimensions and changes from the original part in the existing clutch are stated. For the purpose of modeling the clutch plate, the following parts are made: a friction plate, a leaf spring, a main and side plate, a hub, damper springs and pins. Meanwhile, for the second component: a pressure plate, a diaphragm, pivot rings, a cover, a leaf spring and, once again, pins. Both models are compared to the originals and, finally, the success of the entire project is evaluated
Protection against indirect contact
No full textTema diplomskog rada je zaštita od indirektnog dodira. Pomoću rada smo objasnili pojmove vezane uz indirektni dodir te i samu definiciju indirektnog dodira. Također objasnili smo i način nastajanja indirektnog dodira te njegovu problematiku koja je vezana uz čovjeka. Nakon objašnjenja problematike naveli smo i objasnili zaštitne uređaje te njihovu glavnu zadaću unutar električne mreže u koju su implementirani. Osnovna zadaća zaštite od indirektnog dodira je zaštita čovjeka od mogućnosti dodira dijelova strujnih kruga koji su greškom došli pod napon te nastanka strujnog udara. Sam način izvođenja zaštite od indirektnog dodira smo objasnili pomoću projekta elektroinstalacije jedne stambene zgrade. Prikazali smo način odabira same zaštite, te proračunima pokazali ispravan odabir veličine zaštitnih uređaja.The topic of the graduation thesis is protection from indirect contact. We explained the terms related to indirect touch and the very definition of indirect touch. Also explained the way indirect contact is created and its problems related to humans. After explaining the problem, we listed and explained the protective devices and their main task within the electrical network in which they are implemented. The basic task of protection against indirect contact is to protect a person from the possibility of touching parts of circuits that have accidentally come under voltage and causing an electric shock. We have explained the method of protection against indirect contact using the electrical installation project of a residential building. We showed the way to choose the protection itself, and showed the correct selection of the size of protective devices with calculations
Sensitivity and Noise calculation of 4th-order biquartic HP Filter
No full textU ovom je radu napravljena realizacija visoko propusnog filtra četvrtog reda u bikvartnoj strukturi s aproksimacijom po Besselu, s aproksimacijom po Chebyshevu kao i realizacija visoko propusnog filtra četvrtog reda u kaskadnoj strukturi s aproksimacijom po Besselu. Na temelju parametara iščitanih iz tablica dobivene su prijenosne funkcije nisko propusnih filtara nad kojima je izvršena frekvencijska NP - VP transformacija kako bi se dobile normirane prijenosne funkcije visoko propusnih filtara. Denormiranje je izvršeno na graničnoj frekvenciji of 4 kHz te je napravljena analiza frekvencijskih i vremenskih karakteristika normiranih i denormiranih prijenosnih funkcija i usporedba frekvencijskih i vremenskih karakteristika denormiranih prijenosnih funkcija filtra s aproksimacijom po Besselu i filtra s aproksimacijom po Chebyshevu. Nadalje se izvršila realizacija filtarskih struktura s normiranim i denormiranim elementima u sve tri strukture, te se u svrhu provjere izvršila analiza frekvencijskih i vremenskih karakteristika u programu LTSpice. Nadalje se analizirala Schoefflerova osjetljivost filtarskih realizacija te su se uspoređivale osjetljivosti između filtra s aproksimacijom po Besselu i filtra s aproksimacijom po Chebyshevu, kao i filtra s aproksimacijom po Besselu u kaskadnoj strukturi s filtrom u strukturi bikvarta. Potom je napravljena "Monte Carlo" analiza filtra s aproksimacijom po Besselu u kaskadnoj strukturi s filtrom u strukturi bikvarta. U idućem je poglavlju izvršen izračun šuma zadanog filtra gdje se ukratko opisao šum i analizirani termički šum. Grafički su prikazane karakteristike šuma pasivnih elemenata, operacijskih pojačala te pojedinih sekcija, kao i ukupan šum filtra u bikvartnoj strukturi s aproksimacijom po Besselu. U zadnjem se poglavlju prikazala realizacija realnog filtra s realnim vrijednostima elementima, prikazane su frekvencijske i vremenske karakteristike te je napravljena shema spajanja filtra te izrada i izgled PCB pločice s ostalim potrebnim elementima.In this paper, a fourth-order high-pass filter in a biquad structure with Bessel approximation, a fourth-order high-pass filter with Chebyshev approximation, and a fourth-order high-pass filter in a cascade structure with Bessel approximation are realized. Based on the parameters read from tables, the transfer functions of low-pass filters were obtained, and a frequency LP - HP transformation was performed to derive the normalized transfer functions of the high-pass filters. Denormalization was carried out at the cutoff frequency , and an analysis of the frequency and time characteristics of the normalized and denormalized transfer functions was conducted. A comparison of the frequency and time characteristics of the denormalized transfer functions between the Bessel and Chebyshev approximations was made. Furthermore, the implementation of filter structures with normalized and denormalized elements in all three structures was performed, and an analysis of the frequency and time characteristics was conducted in LTSpice for verification purposes. Additionally, the Schoeffler sensitivity of the filter implementations was analyzed, comparing the sensitivities between the Bessel and Chebyshev approximations, as well as the Bessel approximation in the cascade structure versus the biquad structure. A Monte-Carlo analysis of the Bessel approximation filter in the cascade structure and the biquad structure was then performed. The following chapter includes a noise calculation for the given filter, briefly describing noise and analyzing thermal noise. Graphical representations of the noise characteristics of passive components, operational amplifiers, and individual sections, as well as the total noise of the Bessel approximation filter in the biquad structure, are presented. The final chapter presents the realization of a real filter with real element values, showcasing the frequency and time characteristics, the filter connection diagram, and the design and layout of the PCB with the necessary components