Hello readers!
This month ENSA had the great pleasure to hold the TRUSS
annual plenary in Santander (Spain). During this 2-days meeting, the members of
the TRUSS consortium visited the ENSA’s facilities and saw 3 huge steam
generators ready to be shipped to the Beaver Valley NPP. The early stage researchers,
we also had the opportunity to attend a presentation of Prof. Castillo on
extreme value statistics and to share the progression of our respective research.
Picture taken during
my oral presentation
Regarding my personal achievements, I can proudly say that
after a general review of the different topics involved, I am able to understand
the ENSA methodology and implement it into the ANSYS FE software through ASCII macros.
As you can imagine, the numerical analysis of the complex behaviour of racks in
seismic conditions is not an easy task. ENSA methodology can be divided into 4
parts. The food for though is summarized hereafter:
I.
Hydrodynamic
masses concept: inertial coupling effects of the surrounding water volume
are replaced by the equivalent mass of water vibrating with each rack. The fluid
is treated as a virtual extension of the structure changing its effective mass.
II.
Thermal
analogy: If the
fluid is inviscid and incompressible, its velocity field satisfies the Laplace
equation (∇2Φ=0), and the associated pressure field can
be determined via the Bernoulli equation. Therefore the potential flow shows a complete analogy with
the steady-state heat conduction phenomena which can be used to assess the
hydrodynamic masses in a cost-effective way.
III.
Dynamic
analysis: A simplified wired model maintaining the original natural frequencies
is used to perform a cost-effective full transient analysis.
IV.
Stress
analysis: Resulting loads and displacements are transferred from the dynamic
model to a detailed FE model in order to check local stresses and
instabilities.
This knowledge will allow me to automatically generate my own
series of numerical outputs. It is a basic starting point, as I count on comparing
them with experimental data to evaluate the uncertainties inherent to the
methodology.
See you down here soon!
