• Moussawi, Ali

Abstract

The experimental identication of mechanical properties is crucial in mechanicsfor understanding material behavior and for the development of numerical models.Classical identi cation procedures employ standard shaped specimens, assume thatthe mechanicalelds in the object are homogeneous, and recover global properties.Thus, multiple tests are required for full characterization of a heterogeneous object,leading to a time consuming and costly process. The development of non-contact, full- eld measurement techniques from which complex kinematicelds can be recordedhas opened the door to a new way of thinking. From the identi cation point of view,suitable methods can be used to process these complex kinematicelds in order torecover multiple spatially varying parameters through one test or a few tests. Therequirement is the development of identi cation techniques that can process thesecomplex experimental data.This thesis introduces a novel identi cation technique called the constitutivecompatibility method. The key idea is to de ne stresses as compatible with theobserved kinematiceld through the chosen class of constitutive equation, makingpossible the uncoupling of the identi cation of stress from the identi cation of thematerial parameters. This uncoupling leads to parametrized solutions in cases where5the solution is non-unique (due to unknown traction boundary conditions) as demonstratedon 2D numerical examples. First the theory is outlined and the method isdemonstrated in 2D applications. Second, the method is implemented within a domaindecomposition framework in order to reduce the cost for processing very largeproblems. Finally, it is extended to 3D numerical examples. Promising results areshown for 2D and 3D problems.

Topics

• impedance spectroscopy
• theory