Thermal Modal Performance of Composite Laminates Embedded with Anti-Symmetric Oblique Coupling Gradient Pre-Strained SMA Wires for Suppressing Resonance

Abstract

As an extension of conventional gradient, anti-symmetric oblique coupling gradient has a superior modal modification ability on composite laminates embedded with pre-strained shape memory alloys (SMA) wires, which is beneficial to suppress modal resonance of composite laminates in the thermal environment. This paper presents an anti-symmetric oblique coupling gradient model of SMA along the thickness direction. That is, the gradient model of SMA wires’ orientation and the positive and negative gradient model of SMA volume fraction. Considering the internal force of composite laminates composed of the pre-strain recovery force of SMA and the thermal expansion force of the substrate, the free vibration equation of composite laminates with additional internal forces energy is derived from first-order shear plate theory and Hamilton principle. The influence of coupling gradient parameters on the thermal modal performance of SMA composite laminates is analyzed and verified by experiments. The proposed anti-symmetric oblique coupling gradient SMA wires’ distribution form effectively exerts the recovery stress generated by SMA tensile pre-strain, i.e., effectively improves the stiffness and critical buckling temperature. Coupling gradient distribution broadens the frequency modulation range, which makes the fine regulation of the natural frequency and critical buckling temperature feasible.

Modal Performance Analysis of Compressor for Active Control of Acoustic Radiation

“…Due to the similarity and correlation with structural modes, the theoretical research of acoustic radiation modes has become mature [11][12][13][14]. However, in solving practical active control problems, the research conditions are still quite harsh.…”

“…By mode decoupling of the motion equation, it can be recognized that the structure motion is the superposition of multi-order vibration modes. Therefore, the analysis of vibration problem will be converted into the study of excitation degree of each order of modes, so as to realize the suppression of vibration from the mode angle.Due to the similarity and correlation with structural modes, the theoretical research of acoustic radiation modes has become mature [11][12][13][14]. However, in solving practical active control problems, the research conditions are still quite harsh.…”