Analytical and numerical study of the behavior of FGM hydrogel actuators

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Analytical and numerical study of the behavior of FGM hydrogel actuators

ارائه دهنده: Provider: Amir Ghasemkhani

اساتید راهنما: Supervisors: Hashem Mazaheri (Ph.D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Rahman Seifi (Ph.D) - Abbas Fadaei (Ph.D)

زمان و تاریخ ارائه: Time and date of presentation: February 2020

مکان ارائه: Place of presentation: آمفی تئاتر دانشکده مهندسی

چکیده: Abstract: Hydrogels are categorized as smart polymeric materials which undergo large deformations when they are subjected to different physical and chemical stimuli in contact with water. Regarding to these characteristics, these materials can be applied as sensors and actuators. In this work, analytical and numerical methods were employed to study swelling behavior of a cylindrical shell and a micro-beam made of a functionally graded temperature sensitive hydrogel. Cross-linking density of cylindrical shell and micro-beam have gradient property in radial and thickness direction respectively. The analytical model was first developed, then finite element solution of the under-study functionally graded hydrogel shell and micro-beam were performed by implementing the material model in Abaqus software by writing a user-defined subroutine. In this regard, the functionally graded hydrogel shell and micro-beam were modeled as multi-layered body with discrete material properties. A good agreement between the analytical results and the numerical simulations were observed and validity of the numerical solutions was confirmed. These materials have another important applications including microfluidics in which the fluid-solid interaction (FSI) have an important effect on their performance. Due to FGM materials advantages, utilizing these materials is really attractive. In this thesis in addition to analytical and numerical study of cylindrical shell and micro-beam, FSI effects are also studied by considering it in simulations. In this regard, first the appropriate numerical tool for finite element modeling of a functionally graded model is developed and verified and then, implemented for FSI simulation. Also, in this thesis, linear and exponential distribution of cross-link density as well as homogenous cases are studied to distinguish the FGM effects. Finally, the micro-valve behavior simulated without considering the FSI effects so that we can study the effects of these interactions. The results indicate that FSI was of high importance and had considerable effects on micro-valve and micro-beam parameters particularly closing temperature and fluid flow rate. Key Words: Hydrogesl temperature-sensitive, micro-beam,micro-valve,analytical,numerical,FSI

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