
Carlos E. S.
Cesnik
Visiting Associate Professor
of Aeronautics and Astronautics
from the University of Michigan
Research
With the increasing
complexity of aerospace systems, the engineer has fewer opportunities
to gain experience and insight from previous projects. Therefore, computer
simulation is a major avenue for training and decisionmaking support
in the design of future aerospace structural concepts. Those structures
will most likely be nonhomogeneous, anisotropic, and composed of passive
and active materials. New approaches will have to address the complexities
inherent to the actual structure while providing the computational characteristics
necessary for their integration in a multidisciplinary environment. With
this in mind, Professor Cesnik's main research interests are in the general
field of structural mechanics, structural dynamics, and aeroelasticity,
with emphasis on designoriented methodologies, as reflected in the following
activities.
Wing Structural
Modeling:
Development of highfidelity models of builtup wing structures for structural
dynamics/aeroelastic applications. Aeroelastic analysis is an essential
part of any aircraft
multidisciplinary design. The structural model used to discretize the
wing and other components of the aircraft is usually a combination of
plates, membranes, rods, shear panels, etc. However, this type of discretization,
while accounting for some details of the aircraft component, results in
high mesh preparation time and high computational costs. A new platelike
finite element is envisioned that will asymptotically characterize the
behavior of the original threedimensional builtup cell with fewer degrees
of freedom and much simpler topology. At the end, relations are sought
for stress/strain recovery at any point of the original structure.
Aeroelastic Model
for Control Design:
Highfidelity loworder aeroelastic models are pursued to provide the
ideal representation of the aircraft for robust control design. The perfect
match between the structural and aerodynamic models allows for a reduced
order model while preserving the fidelity required to characterize the
aircraft plant.
Active Helicopter
Blade Modeling:
Modeling of beam and platelike nonhomogeneous, anisotropic structures
with the presence of active materials as sensors and actuators. The use
of active materials embedded in a composite structure provides a means
of actively controlling its behavior, though increasing the complexity
of its analysis even more. Since most aircraft structural components have
one (beamlike) or two (platelike) dominant dimensions, specialized theories
can be developed to systematically account for all the important threedimensional
(3D) effects present on those structures. The designer would not have
to bear either the cost of 3D finite element discretization or the loss
of accuracy inherent in any simplified representation of the actual structure.
Examples of such application are vibration reduction and control augmentation
of helicopter rotor blades.
Aeroelastic Interface:
Development of finiteelementlike approaches for data interface. In the
area of Computational Aeroelasticity, there is the issue of data communication
between disciplines. The growing use of Computational Fluid Dynamics (CFD)
codes coupled with Computational Structural Mechanics (CSM) ones requires
accurate data transfer between the corresponding grid and mesh. The transformation
method should be flexible to rapidly model complex interface geometries.
Studies have shown that this could be accomplished by a finiteelementlike
approach.
Also pursuing reseach
in:
Automatic mesh generation and graphical user interface for finiteelement
models; lowcost structural concepts for General Aviation applications;
manufacturing cost
models for composite structures and their role in the structural design.
