Vpliv kontaktne nelinearnosti na dobo trajanja strukture pri vibracijskem utrujanju

Mušič, Tim (author), Česnik, Martin (mentor)

Zaradi zračnosti realni izdelki pogosto izkazujejo nelinearno naravo. Namen naloge je preveriti, kako pri vzbujanju izdelka z naključnim signalom kontaktna nelinearnost vpliva na hitrost akumulacije poškodb. Najprej je opravljen pregled reševanja linearnih in nelinearnih sistemov, pri čemer je bila preizkušena metoda balansiranja harmonikov. V nadaljevanju je poudarek na nelinearnem sistemu z dvema prostostnima stopnjama s kontaktno nelinearnostjo, primerjajo pa se trije različni kontakti (guma, plastika, kovina). Rezultati numeričnih izračunov so primerjani z rezultati eksperimenta, kjer je ugotovljena zadovoljiva zmožnost napovedi odziva sistema. Na podlagi rezultatov eksperimenta je narejena analiza vpliva nelinearnosti in statističnih cenilk na hitrost akumulacije poškodbe. Slednja se določi z metodo rainflow, ki služi kot referenca za preverjanje spektralnih števnih metod. Rezultati meritev kažejo, da kontaktna nelinearnost lahko negativno vpliva na življenjsko dobo na enem delu sistema in pozitivno na drugem delu sistema.

• Language: Slovenian
• Keywords: strukturna dinamika, kontaktna nelinearnost, vibracijsko utrujanje, numerična analiza dinamike nelinearnega sistema, metoda balansiranja harmonikov
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [T. Mušič]
• Year: 2023
• Number of pages: XXIV, 79 str.
• PID: 20.500.12556/RUL-148979
• UDC: 539.433:538.913(043.2)
• COBISS.SI-ID: 166167811
• Publication date in RUL: 02.09.2023

MUŠIČ, Tim, 2023, Vpliv kontaktne nelinearnosti na dobo trajanja strukture pri vibracijskem utrujanju [online]. Master’s thesis. Ljubljana : T. Mušič. [Accessed 14 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=148979

Secondary language

• Language: English
• Title: Effect of contact nonlinearity on the vibration fatigue life of a structure

Abstract

Due to the clerances, real products often exhibit nonlinear behavior. The purpose of this study is to investigate how contact nonlinearity affects the rate of damage accumulation when exciting the product with a random signal. An overview of solving linear and nonlinear systems was conducted, where the harmonic balancing method was examined. The focus is then on a nonlinear system with two degrees of freedom and contact nonlinearity, comparing three different contacts (rubber, plastic, metal). The results of numerical calculations are compared with experimental results, demonstrating a satisfactory ability to predict the system's response. Based on the experimental results, an analysis of the impact of nonlinearity and statistical estimators on the rate of damage accumulation is performed. This is determined using the rainflow method, which serves as a reference for verifying spectral counting methods. Measurement results show that contact nonlinearity can have a negative impact on the lifespan of one part of the system and a positive impact on another part of the system.

• Keywords: structural dynamics, contact nonlinearity, vibration fatigue, numerical analysis of dynamics of a nonlinear system, harmonic balancing method