The development of an efficient procedure for 3d modeling and finite element simulation of metal foams is one of the greatest challenges for engineer researchers nowadays. Creating 3d CAD model is alone a demanding engineering task due to its extremely complex geometry, and the proper finite element analysis process is still in the center of the research. The increasingly widespread application of the metal foams, e.g. in vehicle and medical industry, requires this knowledge in the design phase. A closed-cell metal foam is studied using different analyzing methods where the aim is to collect information about the composition and geometry (structure) that is satisfactory for the later research. Using statistical methods microscopic, X-ray and surface analyzing studies on the specimens produced according to the concerning standard are evaluated. The main goal of this part of the project is to obtain structural information and to determine the homogeneity or the in-homogeneity property of the metal foam specimens taken from different locations.

Uncontrolled vibrations reduce safety, durability, efficiency, comfort, and overall performance in engineering systems; therefore, effective vibration damping is essential. Viscoelastic materials play a crucial role in vibration damping due to their ability to dissipate energy, their tunable properties, and their broad range of applications. Ethylene vinyl acetate (EVA), a thermoplastic copolymer with inherent viscoelastic properties, is widely used in vibration-damping applications. However, its damping capacity can be further improved through cross-linking. This study investigates the damping performance of ethylene vinyl acetate with 18 wt% vinyl acetate content (EVA-18) modified with 1–4 wt% dicumyl peroxide (DCP) as a cross-linking agent. Mechanical properties were measured through tensile testing, and viscoelastic behaviour was characterized using Dynamic Mechanical Analysis (DMA). Damping performance was evaluated by Experimental Modal Analysis (EMA) in free-layer damping (FLD) and constrained-layer damping (CLD) configurations. Frequency-dependent system loss factors were predicted using B.C. Nakra’s analytical formulations and compared with experimental results. In FLD, EVA-1 showed the highest average loss factor (0.034), whereas in CLD, EVA-0 exhibited the highest loss factor (0.069). These results clarify how controlled DCP cross-linking modifies the viscoelastic and damping behaviour of EVA-18 and indicate its potential for use in vibration-control applications in automotive, aerospace, and structural engineering.

Napjaink gépjármű iparában gyártói - , és szerviz oldalról is fontos igény az adott alkatrészek várható élettartamának rendkívül precíz meghatározása. Ennek módja jelenleg a rendelkezésre álló tekintélyes elméleti tudástár felhasználása mellett a műszaki gyakorlatból és gyártási-, felhasználási tapasztalatokból álló tudásbázis alkalmazása. Anyagtudományi, és törésmechanikai aspektusból ez a terület ma már kellőképpen lefedettnek tekinthető. Azonban a maradó feszültségek, melyek additívan keletkeznek már az alapanyag gyártás lépéseinél, valamint az esetleges további mechanikai alakítások, és hőkezelések, felületkezelések során, jelenleg nem megfelelően elkülöníthetők. Ennek technológiai vizsgálataira több párhuzamos fizikai módszer létezik, melyek alkalmazhatósága mindig a gyártómű döntésén, az ott dolgozó mérnökök tapasztalataira építve valósul meg. Ez a terület tehát még nem egyértelműen szabványosított így még vállalaton belül is adódhatnak eltérések egy-egy módszer megítélése kapcsán.

Belt-in-Oil (BIO) timing belts operate under repeated tooth engagement, cyclic deformation, elevated temperatures, and continuous contact with engine oil. This study comparatively evaluated the surface degradation and tooth-profile geometry of BIO and dry-running timing belts used under real operating conditions. Two BIO belts (S1: 80,000 km; S2: 120,000 km) and one dry-running belt (S3: 80,000 km) were analysed using 2D and 3D digital optical microscopy. Sample S1 showed localised material loss and exposure of fibrous structural elements, mainly near the tooth grooves and roots. More extensive delamination-like damage was observed on S2, whereas S3 exhibited localised crack-like surface damage. Mean profile depths measured at six circumferential locations were 2.477 ± 0.439 mm for S1 and 2.178 ± 0.272 mm for S3, corresponding to mean relative deviations of −23.8% and −37.8%, respectively, from the catalogue reference geometries. The results indicate that local surface degradation and tooth-profile geometric deviation represent distinct condition characteristics. Because the belts originated from different engine designs and material systems, the independent effects of oil exposure and mileage cannot be isolated.