Quasicrystals can carry, in addition to the classical phonon displacement field, a phason displacement field, which requires a generalized theory of elasticity. In this paper, the third-order strain invariants (including phason strain) of icosahedral quasicrystals are determined. They are connected with 20 independent third-order elastic constants. By means of non-linear elasticity, phason stra...

A numerical scheme is proposed to generate a microstructure of a martensitic material when subjected to arbitrary boundary conditions. The deformation gradient is decomposed multiplicatively into an elastic strain and a transformation strain. The elastic part ensures compatibility between the (conforming) finite elements. A global energy minimization scheme similar to Genetic Algorithms, yet su...

© 2014 Materials Research Society MRS BULLETIN • VOLUME 39 • FEBRUARY 2014 • www.mrs.org/bulletin Introduction The development of (electro)catalytic materials has traditionally relied on the design of new compositions and structures. In principle, previously unseen and desirable properties can be obtained by perturbing the structure of existing materials with elastic strain. Uncovering the fund...

In this paper we study the wedge disclination within the elastoplastic defect theory. Using the stress function method we found exact analytical solutions for all characteristic fields of a straight wedge disclination in a cylinder. The elastic stress, elastic strain, elastic bend-twist, displacement and rotation have no singularities at the disclination line. We found a modified stress functio...

We develop a thermodynamic framework for modeling nonlinear ultrasonic damage sensing and prognosis in materials undergoing progressive damage. The framework is based on the internal variable approach and relies on the construction of a pseudo-elastic strain energy function that captures the energetics associated with the damage progression. The pseudo-elastic strain energy function is composed...

A method to measure the mechanical behavior of Pt thin films was developed. It employs high magnification optical microscopy and Digital Image Correlation to extract sub-micron (100 nm local displacement resolution) deformation fields in free-standing thin films and calculate their elastic/plastic properties as a function of strain rate. In this study, the specimen gauge length and thickness we...

We investigate the free energy and the concentration of monovacancies in strained face-centered-cubic (fcc) hard-sphere crystals for several densities at and above melting. We use the conventional molecular dynamics method for simulations and employ a bias insertion method to extract properties of a monovacancy. We study two distinct constant-volume strains, considering a simple shear and an or...