Vpliv konstrukcijskih parametrov na dobo trajanja zračne vzmeti

Bešter, Tomaž (author), Nagode, Marko (mentor), Fajdiga, Matija (comentor)

V doktorskem delu je predstavljena analiza vpliva konstrukcijskih parametrov na dobo trajanja zračne vzmeti. Nekateri obravnavani konstrukcijski parametri so lastnosti same vzmeti (kot korda, razmerje premerov), medtem ko so drugi lastnosti podvozja (dolžina ročice, ekscentričnost vzmeti, ekscentričnost ročice, naklon). S pomočjo Taguchijevih metod je bil analiziran vpliv šestih konstrukcijskih parametrov in treh povezav med izbranimi parametri. Doba trajanja pri pomiku vzmeti ±50mm je bila uporabljena kot kvalitativni kriterij v Taguchijevi analizi. Za izračun dobe trajanja smo uporabili Wöhlerjeve krivulje iz predhodnih raziskav in amplitude napetosti, ki smo jih izračunali z metodo končnih elementov. Model končnih elementov je bil preverjen s tremi preizkusi, kjer smo merili premer vzmeti in tlak v mehu med enim obremenitvenim ciklom. Razlike med izmerjenimi in izračunanimi veličinami so bile relativno majhne, zato je bil model končnih elementov uporabljen za izračun amplitude napetosti potrebne za določitev dobe trajanja. Z analizo variance smo dokazali, da imata razmerje premerov in ekscentričnost ročice bistven vpliv na dobo trajanja. Analiza interakcij med parametri je pokazala močno interakcijo med razmerjem premera in kotom korda medtem ko ostale obravnavane interakcije niso imele bistvenega vpliva. Oba parametra, ki sta odvisna od same vzmeti imata bistven vpliv na dobo trajanja. Razmerje premerov ima neposreden vpliv na dobo trajanja, medtem ko ima kot korda vpliv na dobo trajanja posredno preko interakcije z razmerjem premerov. Od parametrov povezanih z geometrijo podvozja, ima zgolj ekscentričnost ročice znaten vpliv na dobo trajanja.

• Language: Slovenian
• Keywords: zračne vzmeti, kompozitni materiali, metoda končnih elementov, utrujanje
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [T. Bešter]
• Year: 2020
• Number of pages: XXVIII, 127 str.
• PID: 20.500.12556/RUL-120208
• UDC: 62-272.82:519.62(043.3)
• COBISS.SI-ID: 30253827
• Publication date in RUL: 17.09.2020

BEŠTER, Tomaž, 2020, Vpliv konstrukcijskih parametrov na dobo trajanja zračne vzmeti [online]. Doctoral dissertation. Ljubljana : T. Bešter. [Accessed 23 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=120208

Secondary language

• Language: English
• Title: Influence of construction parameters on airspring lifetime

Abstract

The doctoral thesis presents an analysis of air spring design factors to determine their influence on air spring fatigue life. Some of the analysed design factors relate to the air spring itself (cord angle, diameter difference), while the other design factors relate to the design of the undercarriage (lever length, eccentricity, lever eccentricity, inclination). Using Taguchi methods, six design parameters and three interactions between the selected parameters were analysed. Life spans of air springs loaded with ±50mm displacement amplitude were used as the Taguchi analysis qualitative criteria. To determine life span, S-N curves from previous investigations and stress amplitudes calculated with FEM were used. The finite element model was validated with three experiments where air spring diameter and pressure were measured during one load cycle. The differences between the measured and calculated quantities were relatively small, therefore the finite element model was used to calculate stress amplitudes required for the calculation of life spans. The analysis of variance presented here has shown that the diameter difference and lever eccentricity have significant influence on air springs life span. Interaction analysis has shown significant interaction between the diameter difference and cord angle, while other interactions haven’t shown a significant influence on the life span. Both parameters relating to the air spring itself have a significant influence on the air spring’s life span. The diameter difference has a direct influence, while the cord angle has indirect influence due to interaction between the diameter difference and the cord angle. Among design parameters relating to the design of the undercarriage, only lever eccentricity has a significant influence on an air spring’s life span.

• Keywords: air spring, composite materials, finite element method, fatigue