Vpliv velikosti deformacije in temperature na časovno odvisno relaksacijo elastomernega tesnila

Vovk, Jaka (author), Slemenik Perše, Lidija (mentor), Halilovič, Miroslav (comentor)

Za polimerne materiale je značilno, da se njihove lastnosti s časom spreminjajo. Eden izmed značilnih časovno odvisnih procesov je tudi proces relaksacije. To je proces, pri katerem se napetosti v materialu, ki je v deformiranem stanju, s časom zmanjšujejo. V nalogi je obravnavan primer tesnila izdelanega iz silikonske gume, za katerega smo ovrednotili napetostno stanje in tesnilni tlak v odvisnosti od temperature po pretečenem času enega leta. Osnovne materialne lastnosti, potrebne za definicijo materialnega modela, smo določili na podlagi meritev natezne karakteristike in strižne relaksacije. Ustreznost materialnega modela smo preverili z numerično simulacijo meritve strižnega relaksacijskega modula. Ugotovljeno je, da se napetosti v tesnilu s časom zmanjšujejo in po enem letu pri temperaturi 20°C dosegajo 76,6% začetne vrednosti. Z naraščanjem temperature tesnila se proces zmanjševanja napetosti in posledično tudi tesnilnega tlaka pospeši.

• Language: Slovenian
• Keywords: tesnila, polimeri, silikonska guma, relaksacija napetosti, časovno temperaturna superpoziija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [J. Vovk]
• Year: 2022
• Number of pages: XXII, 56 str.
• PID: 20.500.12556/RUL-136472
• UDC: 539.3:62-762:519.876.5(043.2)
• COBISS.SI-ID: 106984451
• Publication date in RUL: 06.05.2022

Secondary language

• Language: English
• Title: The effect of strain and temperature on time-dependent relaxation of elastomeric seal

Abstract

It is characteristic of polymeric materials that their properties change over time. One of the characteristic time-dependent processes is also the relaxation process. This is a process in which the stresses in a material that is in a deformed state decrease over time. The paper deals with the case of a seal made of silicone rubber, for which we evaluated the stress state and sealing pressure as a function of temperature after one year. The basic material properties required for the definition of the material model were determined on the basis of measurements of tensile characteristics and shear relaxation. The adequacy of the material model was verified by a numerical simulation of the shear relaxation module measurement. It has been found that the stresses in the seal decrease over time and reach 76.6% of the initial value after one year at a temperature of 20°C. As the temperature of the seal increases, the process of reducing the stresses and consequently also the sealing pressure is accelerated.

• Keywords: seals, polymers, silicone rubber, stress relaxation, time temperature superposition