2020-01-14 13h00: A. SLADEN et Y. HELLO, CNRS GEOAZUR

Title : Fiber optic cables for the study of the oceans and the Earth system

Distributed Acoustic Measurement (DAS) on optical fiber is a recent instrumental approach that allows to transform any optical fiber into a dense network (m) of seismo-acoustic sensors (0.1-1000Hz) over large distances (50km+). It is therefore a solution that can address the problems of cost, complexity and reliability of the best current systems for seafloor instrumentation. After an introduction to the technology and the presentation of the first results, we will discuss the current limitations and the envisaged and possible strategies to overcome them.




Juliette DRUPT

PhD student Funding: E-mail: juliette-drupt at etud.univ-tln.fr LinkedIn: https://www.linkedin.com/in/juliette-drupt-3a7051159/ Bio I recently graduated from the Ecole de Mines de Saint-Etienne that ended with a one-year specialization in robotics at the Read more →

PhD Defense of Maxime Chalvin, July the 9th

Additive manufacturing of tubes by multi-axis robotized wire deposition :
Trajectory generation and optimization

Additive manufacturing through Directed Energy Deposition (DED) enables small batches
of parts to be rapidly manufactured. However, manufacturing trajectories usually used
for the manufacture of overhanging parts require the use of supports, material which
is not useful for the finished part and time consuming. If multi-axis trajectories can be
used to avoid them, they present generally a heterogeneous local inter-layer distance, thus
requiring a variation of the deposition parameters to adapt the layer height ; variation that
can be harmful to the mechanical characteristics of the final part. This thesis first proposes
a constant local inter-layer trajectory generation method for DED additive manufacturing
of tubular parts defined by parametric curves and which can have profile radius variations.
The proposed trajectories have been validated by robotized manufacturing trials of polymer
parts. Since the rotation about a coaxial deposition tool axis has no impact on the deposit,
the use of 6-axis robots offers a redundancy. Using this redundancy, a layer by layer
optimization of the trajectory in the robot space is then proposed. In a constrained robot
configuration, the trajectory optimization allows the manufacturing of parts that cannot
be manufactured in the usual way, and improves the geometrical quality of the parts with
a better repeatability.