Utrujanje magnezijevih zlitin za preoblikovanje pri cikličnem obremenjevanju

Šolinc, Urša (author), Nagode, Marko (mentor), Šeruga, Domen (comentor)

Doktorsko delo predstavlja rezultate malocikličnega in naključnega enoosnega obremenjevanja preizkušancev iz valjane magnezijeve zlitine AZ31. Predstavljen je Prandtlov reološki model za simuliranje kompleksnega odziva magnezijeve zlitine AZ31 z metodo Prandtl-Ishlinskiijevih histereznih operatorjev. Prandtlov reološki model na osnovi znanega odziva na malociklično obremenjevanje hitro in natančno simulira odziv magnezijeve zlitine AZ31 na naključno enoosno obremenjevanje pri konstantni temperaturi. Za izračun deformacijske energije, ki se disipira med cikličnim obremenjevanjem magnezijeve zlitine AZ31, je predstavljen Prandtlov energijski model, ki sloni na Prandtlovem reološkem modelu. Prandtlov energijski model računa deformacijsko energijo z metodo Prandtl-Ishlinskiijevih histereznih operatorjev, ki omogoča neodvisnost rezultata od računskega koraka. S tem pristopom na hiter in natančen način določimo vrednost disipirane deformacijske energije, s katero lahko ocenimo življenjsko dobo pri utrujanju magnezijevih zlitin.

• Language: Slovenian
• Keywords: reološki model, materialni model, energijski model, ciklično obremenjevanje, naključna amplituda, magnezijeve zlitine, Mg AZ31, Prandtlovi operatorji, histerezni operatorji, deformacijska energija, življenjska doba pri utrujanju
• Work type: Dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [U. Šolinc]
• Year: 2020
• Number of pages: XXVI, 90 str.
• PID: 20.500.12556/RUL-121818
• UDC: 621.86.01:669.721.5:620.178.3(043.3)
• COBISS.SI-ID: 36396035
• Publication date in RUL: 31.10.2020

Secondary language

• Language: English
• Title: Wrought magnesium alloy fatigue under cyclic loading

Abstract

This thesis presents experimental results of constant and variable amplitude uniaxial loading of magnesium AZ31 alloy sheets at room temperature. A Prandtl rheological model is presented for modelling the complex response of magnesium AZ31 alloy based on the Prandtl-Ishlinskii hysteresis operators. From the known material response to constant amplitude uniaxial loading, the Prandtl rheological model provides a fast and accurate simulation of the magnesium AZ31 alloy response to arbitrary uniaxial loading under isothermal conditions. For calculating the strain energy dissipated in magnesium alloy AZ31 during cyclic loading, a Prandtl energy model is presented which is based on the Prandtl rheological model. The strain energy is calculated continuously throughout the loading procedure, the main advantage of the Prandtl energy model being independence from the incremental step size. This approach gives a fast and accurate calculation of the dissipated strain energy which can be used for estimating the fatigue life of magnesium alloys.

• Keywords: rheological model, material model, energy model, cyclic loading, variable amplitude loading, magnesium alloy, Mg AZ31, Prandtl operators, hysteresis operators, strain energy, fatigue life