Iskanje po katalogu digitalne knjižnice

Opis: In the presented study, a computational model was developed to analyse the wear behaviour of contacting mechanical elements like gears, bearings, etc. The model was built in the framework of the PrePoMax open-source CalculiX FEM (Finite Element Method) solver and enables a detailed analysis of the meshing dynamics of contacting mechanical elements. The model also considers the hyperelastic behaviour of the material in contact and the impact of operating temperature. The developed computational model was evaluated on a spur gear pair, where the pinion made of POM (Polyoxymethylene) was meshed with a support gear made of case-hardened steel 16MnCr5. The computational results were compared with the analytical results according to the VDI 2736 guidelines and experimental results on the real gear pairs. Compared to the standardised procedure according to the VDI 2736 guidelines, the model's main advantage is the geometry updating after a chosen number of loading cycles, enabling a more accurate prediction of wear behaviour under rolling/sliding loading conditions.
Ključne besede: wear, polymer gears, computational modelling, experimental testing
Objavljeno v DKUM: 08.04.2025; Ogledov: 0; Prenosov: 6
Celotno besedilo (5,53 MB)
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Opis: A comprehensive experimental investigation to understand the mechanical properties and fatigue behaviour of glass-reinforced polyamide (PA66 GF30) at different temperatures is presented in this paper. The specimens for quasi-static and fatigue testing were machined from previously extruded plates, where two orientations were considered: (i) the extrusion direction (ED) and (ii) the direction perpendicular to extrusion (PED). Both the quasi-static and fatigue tests were performed under different temperatures (22 ◦C and 100 ◦C). The fatigue tests were performed in a load control regime under pulsating loading (R = 0.1) to create S–N curves for all the temperatures and loading directions. The experimental results of the quasi-static tests showed that the test specimens manufactured in the extrusion direction have better mechanical properties when compared to those of the specimens manufactured perpendicular to the extrusion direction. Furthermore, the analysis of the quasi-static tensile test results showed that tensile strength, yield strength, and the modulus of elasticity are significantly dependent on the temperature and deteriorate when the temperature is increased from 22 ◦C to 100 ◦C. The results of the fatigue tests showed that at both the temperatures (22 ◦C and 100 ◦C), the samples produced in the direction of extrusion exhibited higher fatigue strength than those produced perpendicular to the direction of extrusion. For all the sample orientations, the fatigue strength decreased significantly with increasing temperature. The obtained experimental results could be very useful when designing and dimensioning different dynamically loaded engineering components made of PA66 GF30 subjected to high temperatures.
Ključne besede: PA66 GF30, increased temperatures, fatigue, experimental testing
Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 4
Celotno besedilo (1,93 MB)
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Opis: Abstract In the proposed study, the fatigue analysis of an axisymmetric chiral cellular structure and its modified form, made of stainless steel 316L, is carried out. The main goal of the original structure geometry was to absorb as much mechanical energy as possible with its auxetic behaviour. However, it was found through testing that its response could be improved by modifying the thickness of the struts through the structure. Representative models for the original and modified geometries were generated using a script adapted for this numerical simulation. Three different types of displacement in the shape of sine waves were used to load the structures. A hexagonal mesh was assigned and determined by convergence analysis. An existing material model with the necessary LCF parameters was assigned in the computational analyses. The data from multiple simulations were recorded and presented in graphs that showed how the fatigue life of the structures changed depending on the level of strain. We also analysed stresses and plastic deformations that occur in the structures. The results showed that, despite a better stress distribution, the fatigue life of the optimised structure was shorter in all cases.
Ključne besede: cellular structures, chiral structures, fatigue, strain-life approach, numerical analysis
Objavljeno v DKUM: 10.01.2025; Ogledov: 0; Prenosov: 8
Celotno besedilo (8,28 MB)
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Opis: V diplomskem delu je predstavljen proces depaletizacije, ki smo ga v podjetju AneFill zasnovali za podjetje Radenska; proizvodnjo pijač, ki je bilo naš naročnik. Obravnava se problem pri transportu praznih pločevink s polne palete na transportni trak, ki vodi naprej po transportni liniji do polnilca pijače. Pri tem se je bilo treba osredotočiti na razpoložen prostor in druge omejitve pri rekonstrukciji in nadgradnji iz obstoječega ročno vodenega depaletizerja, da le-ta postane avtomatsko voden depaletizer. Pomeni, da stroj samostojno potisne prazne pločevinke s palete na transportni trak in pri tem tudi odvzame vmesni karton. Ta cikel se ponavlja večkrat, dokler paleta ni prazna. V diplomskem delu je posebej opisano celotno delovanje in snovanje posameznih komponent depaletizerja ob pomoči različnih tipov slik, preračunov in končnega izgleda avtomatiziranega depaletizerja.
Ključne besede: Depaletizacija, rekonstrukcija stroja, depaletizer pločevink
Objavljeno v DKUM: 22.10.2024; Ogledov: 0; Prenosov: 0

Opis: V diplomskem delu je predstavljen potek konstruiranja pnevmatske priprave za montiranje ležajev v podjetju LP Mycron d.o.o. Namen konstruiranja pnevmatske priprave za montiranje ležajev je olajšati in pospešiti način tega postopka, saj imajo v podjetju za izdelati velike serije izdelkov, ki potrebujejo montažo ležajev že več let in so potrebni izboljšave. V delu je predstavljeno delovanje priprave, potek konstruiranja ter primerjava med starim in novim načinom.
Ključne besede: montaža ležajev, pnevmatska priprava, stiskanje, konstruiranje
Objavljeno v DKUM: 07.10.2024; Ogledov: 0; Prenosov: 37
Celotno besedilo (2,93 MB)