Electro-thermo-mechanical analysis of actuator structure made of functionally graded material.

The paper deals with a new approach in analyzing of the actuator systems made of Functionally Graded Materials (FGM) using our new beam finite elements. Weak coupled electro-thermomechanical analysis and spatial continuous variation of material properties are considered for chosen actuator structure. This electrically driven actuator is simple-shaped due to properly chosen variation of material properties to ensure functionality of the actuator at material and physical level instead of the geometric shape level. The solution results will be compared with those obtained by using solid elements of a FEM commercial program

Actuator structure analysis using new electro-thermo-mechanical finite element for functionally graded materials.

Proposed paper deals with electro-thermo-mechanical analysis of chosen actuator structure made od FGM using new finite element derived specially for this purpose. Rectangular cross-section of individual beams that form the von Mises structure with variation of material properties in longitudinal and lateral direction will be considered. Actuator action, electric voltage and temperature peak and also mechanical stress of the structure will be evaluated. Results from the analysis calculated using our new FGM beam finite elements will be compared to results from conventional FEM analysis where standard finite elements will be used

Forced vibration of the aluminum beam using a piezoelectric actuator - experiment and finite element analysis.

This paper deals with the forced vibration of the aluminum beam using a piezoelectric actuator. Cantilever beam was excited by thin piezoelectric film placed near the fix support. The oscillation of the free end of the beam was measured using a laser displacement sensor. The beam's eigenfrequency and damping ratio for the first bending vibration mode was determined experimentally. The beam's deflection when the beam was excited by a piezoelectric actuator was also determined experimentally. The actuator was controlled by a signal generator and high-performance power supply and linear amplifier module for driving piezoelectric actuators. Data from experimental measurements were used to validate the finite element model of the beam with piezoelectric actuator. Results from experimental measurements and numerical simulations were compared

Kinematic and constitutive equations in warping torsion of FGMs beams with spatially varying material properties

The authors gratefully acknowledge financial support by the Slovak Grant Agency of the project VEGA No. 1/0416/21 and by the Slovak Research and Development Agency under Contract no. APVV-19-040

Calculation of the stresses in the tapered FGM beams with varying stiffness

The authors gratefully acknowledge financial support by the Slovak Grant Agency of the project VEGA No. 1/0416/21 and by the Slovak Research and Development Agency under Contract no. APVV-19-0406

The MEMS four-leaf clover wideband vibration energy harvesting device: design concept and experimental verification

In this contribution, we discuss a novel design concept of a high-performance wideband MEMS vibration energy harvester (EH), named four-leaf clover (FLC EH-MEMS) after its circular shape featuring four petal-like mass-spring systems. The goal is to enable multiple resonant modes in the typical range of vibrations scattered in the environment (i.e., up to 4–5 kHz). This boosts the FLC conversion capability from mechanical into electrical energy exploiting the piezoelectric effect, thus overcoming the common limitation of cantilever-like EHs that exhibit good performance only in a very narrow band of vibration (i.e., fundamental resonant mode). The FLC concept is first discussed framing it into the current state of the art, highlighting its strengths. Then, after a brief theoretical introduction on mechanical resonators, the FLC EH-MEMS device is described in details. Finite Element Method (FEM) analyses are conducted in the ANSYS Workbench™ framework. A suitable 3D model is built up to perform modal simulations, aimed to identify mechanical resonant modes, as well as harmonic analyses, devoted to study the mechanical and electrical behaviour of the FLC EH-MEMS (coupled field analysis). The work reports on experimental activities, as well. Physical samples of the FLC EH-MEMS device are fabricated within a technology platform that combines surface and bulk micromachining. Thereafter, specimens are tested both with a laser doppler vibrometer measurement setup as well as with a dedicated shaker-based setup, and the results are compared with simulations for validation purposes. In conclusion, the FLC EH-MEMS exhibits a large number of resonant modes scattered in the tested range of vibrations (up to 15 kHz) already starting from frequencies as low as 200 Hz, and expected levels of converted power better than 10 µW