saberelarem's blog

We present a systematic approach to deal with the modelling and analysis of the cracked rotating shafts behaviour. We begin by revisiting the problem of modelling the breathing mechanism of the crack.

Here we consider an original approach based on the form we give to the energy of the system and then identify the mechanism parameters using 3D computations with unilateral contact conditions on the crack lips.

We present a systematic approach to deal with the modelling and analysis of the cracked rotating shafts behaviour. We begin by revisiting the problem of modelling the breathing mechanism of the crack. Here we consider an original approach based on the form we give to the energy of the system and then identify the mechanism parameters using 3D computations with unilateral contact conditions on the crack lips. A dimensionless flexibility is identified which makes the application of the approach to similar problems straightforward.

We present a systematic approach to deal with the modelling and analysis of the cracked rotating shafts behaviour. We begin by revisiting

the problem of modelling the breathing mechanism of the crack. Here we consider an original approach based on the form we give to the energy of the system and then identify

the mechanism parameters using 3D computations with unilateral contact conditions on the crack lips. A dimensionless flexibility is identified which makes the application

Because of the increasing need of energy, the plants installed by electricity supply utilities throughout the world are becoming larger and more highly stressed. Thus, the risk of turbogenerator shaft cracking is increasing also. The development and propagation of a crack represents the most common and trivial beginning of integrity losses in engineering structures.

A PhD research subject is proposed for students to apply at Arts et Métiers ParisTech.

ParisTech Doctoral Institute and ParisTech local branch in China have launched a coordinated recruitment procedure in the framework of an agreement with the China Scholarship Council (CSC). This program is open to highly qualified Chinese students interested in carrying on doctoral training at ParisTech with financial support of the CSC.

http://paristech-china.com/content/phd-grant-china-scholarship-council

A fully funded PhD scholarship exists in the area of solid mechanics at
the Arts et Métiers ParisTech, CER Angers, France. 
http://www.ensam.fr/en/.

The successful applicant will have a  Masters' degree  in
solid mechanics, physics or applied Mathematics . He/she 
is expected to have very good numerical
skills.

The Corinth Rift in Greece is one of the most active extensional regions in the Mediterranean area (Fig. 1). The Corinth Rift Laboratory project (CRL, http://crlab.eu) is based on the cooperation of various european institutions that merge their efforts to study fault mechanics and related hazards in this natural laboratory where numerous continuous observations are made. The present rift is asymmetric and deformation is very localized.

 An analytical model is developed to study the coupling effects in
cord-rubber composite materials. The analytical model takes into account
the mismatch of stiffness between the cords and the rubber matrix
material, and the twist-extension coupling. The transverse deformation,
i.e., normal to the cords direction is based on the normal modes of a
special system which describes the orthotropic and the coupling
behaviour of cord-rubber composites. The equations of motion for the
cord-composite plates are derived using the principle of virtual work.
Results of deformation and stresses are obtained for some typical
cord-rubber composite plates and are compared to the existing solutions.
The results presented illustrate that the coupling effects are

 The main purpose of this paper is to complete the works presented by
Andrieux and Varé (2002) and El Arem et al. (2003) by taking into
account the effects of shearing in the constitutive equations of a beam
cracked section in bi-axial flexure. The paper describes the derivation
of a lumped cracked beam model from the three-dimensional formulation of
the general problem of elasticity with unilateral contact conditions on
the crack lips. Properties of the potential energy and convex analysis
are used to reduce the three-dimensional computations needed for the
model identification, and to derive the final form of the elastic energy
that determines the nonlinear constitutive equations of the cracked

 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).

 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