Banca de QUALIFICAÇÃO: LEANDRO DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LEANDRO DOS SANTOS
DATE: 31/01/2024
TIME: 09:00
LOCAL: meet.google.com/etp-chbw-uvt
TITLE:

Nonlinear analysis of plane frames considering hyperelastic models through the finite element positional method

KEY WORDS:

computational mechanics; hyperelastic models; positional finite element method; flat structures; plane frames.

PAGES: 44
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Estruturas
SPECIALTY: Mecânica das Estruturas
SUMMARY:

Computational mechanics, particularly the Finite Element Method, has become an essential tool for engineers to simulate the behavior of structures under various conditions. Additionally, hyperelastic models are commonly used to represent the behavior of highly deformable materials, such as elastomers and polymers, which are increasingly utilized in engineering applications. The use of hyperelastic models is suitable for capturing nonlinear stress-strain relationships of materials, but the accuracy of these models may vary depending on material properties and deformation regimes. Therefore, it is important to select an appropriate model for specific conditions of interest. In this context, hyperelastic models including Mooney-Rivlin, Neo-Hookean, Ogden, and Yeoh were implemented in a computational code in FORTRAN using the Finite Element Positional Method along with Reissner's kinematics and the Newton-Raphson method for nonlinear analysis of plane frames with samples of elastomers containing varying percentages of carbon black. Subsequently, the Method of Least Squares was employed to determine the constitutive coefficients of hyperelastic models. The performance of each model was then evaluated by comparing the force vs. displacement curve of the material under study. Ultimately, it was concluded that the Yeoh and Ogden models exhibited consistent values, while the Neo-Hookean and Mooney-Rivlin models deviated. This observation was attributed to the number of constants in the formulation of these models. Furthermore, it can be stated that the use of the positional finite element method for nonlinear analysis of plane frames with hyperelastic models performs well, especially after the modifications proposed in this work to the formulations of hyperelastic models. These modifications consisted of adding the first invariant of deformation from the simple shear formulation to include the consideration of distortion in the specific energy of deformation of hyperelastic models.

COMMITTEE MEMBERS:
Presidente - 1752508 - DANIEL NELSON MACIEL
Externo ao Programa - 1451817 - JOEL ARAUJO DO NASCIMENTO NETO - UFRNExterno ao Programa - 2087565 - RODRIGO BARROS - UFRN