Controlled flextensional actuators essentially involve a compliant mechanism
assembled in association with piezoceramics featuring sensing and actuation of the struc-
ture by the ceramics energy conversion property. For applications that require vibration response
attenuation, these devices account with an active feedback control to regulate disturbances that
might be introduced to the system. In the field of intelligent struc- tures, the
self-monitoring and control assemblage can be largely used in systems such as micro-grippers for
sample handling, hard disk reading [1] and atomic force microscopy. One distinct advantage of this
kind of structure is their higher accuracy when compared to conventional actively controlled
structures because their sensing is distributed instead of being discrete about the response
measurement phenomenon. The control law effec- tiveness in such a controlled system can be
enhanced by designing their elastic structure by means of the Topology Optimization Method
(TOM), since an optimized material distribution within a fixed domain affects the structure
stiffness, vibration modes and re- sponse characteristics. Previous works that apply the TOM in
controlled piezo-actuators aiming vibration suppression focus on the distribution of
piezoceramic material over a host structure either in frequency domain or in time domain [2].
However, the low cou- pling constants of piezoelectric ceramics may reduce the capability of energy
conversion for input displacements or for input voltages in actuating systems. Therefore, in order
to avoid an unfeasible or less effective active control targeting vibration suppression, this work
focuses on the distribution of the host structure and eliminates the dependence on the magnitude of
electro-elastic coupling constants for a satisfactory energy conversion. As stated, the optimized
smart devices proposed in this work involve a host structure ma- terial distribution which is
sensed and actuated by two predefined piezoceramic locations connected through a feedback
architecture, while the system is subjected to a transient input load. Approximations to the
damping matrix coefficients are considered for both the metallic material and the piezoelectric
material, even though the ceramic layers are significantly thinner than the middle layer. The
objective function chosen minimizes the vibration energy of the system subjected to a volume constraint. The dynamic equilibrium equation accounts with an extra damping matrix derived from the current amplification chosen as the
feedback control law, or for short, the Active Velocity Feedback (AVF). The material model
implemented is the Solid Isotropic Material with Penalization (SIMP) for the 4-node solid finite
element with two mechanical degrees-of-freedom (DOFs) per node, and one electrical DOF per
node. A density-based filter eliminates the checkerboard pattern, the sensitivity analysis
is calculated by the adjoint method, and the Sequential Linear Programming (SLP) algorithm is
employed as the optimization procedure. Two- Dimensions (2D) results are presented and the
influence of the gain velocity value over
the final layouts is analyzed.
