Development and validation of thermo-mechanically coupled finite elements for the simulation of the nonlinear time response of multi-layered shape memory alloy beams
type: CreativeWork
description: The scope of the present work is the development of numerically efficient finite elements for the simulation of the transient, thermo-mechanically coupled and non-linear behavior of shape memory alloys (SMA)s. Therefore, the work focuses in two scientific fields: 1) the development of an improved constitutive model describing the SMA behavior and 2) the development of nonlinear thermo-mechanically coupled beam FEs implementing the developed SMA constitutive model. In the first part of the dissertation a new SMA constitutive model is presented which is developed based on the widely recognized constitutive model of Lagoudas et al. (2012). New terms are introduced in the model that enhance its accuracy and eliminate numerical issues encountered by the usage of the baseline model in the FE analysis framework. Furthermore, the model is implemented in the continuum elements of ABAQUS commercial software through a user material subroutine (UMAT). In the second part of the dissertation, beam FEs are developed that incorporate the developed SMA constitutive model and provide significant computational advantages compared to the continuum FEs. The new FEs implement the thermo-mechanically coupled equilibrium equations in conjunction with properly chosen thermo-mechanical field kinematic assumptions for the simulation of the transient response of beam structures which admit various layers of SMA and passive materials. Initially the formulation of a geometrically linear beam FE is presented while subsequently a second formulation is presented, suitable for the simulation of structures which admits large displacements and rotations by capturing their geometrically nonlinear response. The equilibrium equations of both FE formulations are presented and implemented in the nonlinear FE framework of ABAQUS through the UEL subroutine. Therefore, the equations are solved using the Newton-Raphson nonlinear iterative solution technique while the necessary time integrations are performed n…
abstract: The scope of the present work is the development of numerically efficient finite elements for the simulation of the transient, thermo-mechanically coupled and non-linear behavior of shape memory alloys (SMA)s. Therefore, the work focuses in two scientific fields: 1) the development of an improved constitutive model describing the SMA behavior and 2) the development of nonlinear thermo-mechanically coupled beam FEs implementing the developed SMA constitutive model. In the first part of the dissertation a new SMA constitutive model is presented which is developed based on the widely recognized constitutive model of Lagoudas et al. (2012). New terms are introduced in the model that enhance its accuracy and eliminate numerical issues encountered by the usage of the baseline model in the FE analysis framework. Furthermore, the model is implemented in the continuum elements of ABAQUS commercial software through a user material subroutine (UMAT). In the second part of the dissertation, beam FEs are developed that incorporate the developed SMA constitutive model and provide significant computational advantages compared to the continuum FEs. The new FEs implement the thermo-mechanically coupled equilibrium equations in conjunction with properly chosen thermo-mechanical field kinematic assumptions for the simulation of the transient response of beam structures which admit various layers of SMA and passive materials. Initially the formulation of a geometrically linear beam FE is presented while subsequently a second formulation is presented, suitable for the simulation of structures which admits large displacements and rotations by capturing their geometrically nonlinear response. The equilibrium equations of both FE formulations are presented and implemented in the nonlinear FE framework of ABAQUS through the UEL subroutine. Therefore, the equations are solved using the Newton-Raphson nonlinear iterative solution technique while the necessary time integrations are performed n…
author: Σολωμού, Αλέξανδρος
language: en_US
keywords: Finite elements, Shape memory alloys, 669.95, Πεπερασμένα στοιχεία, Κράματα μνήμης σχήματος
date published: 2016-06-21T15:42:33Z
date modified: 2026-07-27T20:29:23Z
provider: University of Patras
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Patras

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10889/9441