research

 In countries with a moderate seismic hazard, the classical methods
developed for strong motion prone countries to estimate the seismic
behaviour and subsequent vulnerability of existing buildings are often
inadequate and not financially realistic. The main goals of this paper
are to show how the modal analysis can contribute to the understanding
of the seismic building response and the good relevancy of a modal model
based on ambient vibrations for estimating the structural deformation
under weak earthquakes. We describe the application of an enhanced modal
analysis technique (frequency domain decomposition) to process ambient
vibration recordings taken at the Grenoble City Hall building (France).

We have recently published a paper on measurements of the density of geometrically necessary dislocations (GND) associated with wedge indentation of a single face-centered cubic crystal. The deformation field is two-dimensional and there are three effective in-plane slip systems that contribute to the plastic slip. We determine the lower bound on the total GND density with a three micrometer spatial resolution. We also show that in certain regions of the domain, the lower bound on total GND density corresponds to the exact total GND density.

 The main purpose of this work is to present a new parallel direct solver: Dissection solver. It is based on LU
factorization of the sparse matrix of the linear system and allows to
detect automatically and handle properly the zero-energy modes, which
are important when dealing with DDM. A performance evaluation and
comparisons with other direct solvers (MUMPS, DSCPACK) are also given
for both sequential and parallel computations. Results of numerical
experiments with a two-level parallelization of large-scale structural
analysis problems are also presented: FETI is used for the global
problem parallelization and Dissection for the local

In this paper, the coupled thermo-mechanical response of shape memory alloy (SMA) bars and wires in tension is studied.It is shown that the accuracy of assuming adiabatic or isothermal conditions in the tensile response of SMA bars strongly depends on the size and the ambient condition in addition to the rate-dependency that has been known in the literature.