Mechanical Properties Of Hollow Glass Microsphere Filled Epoxy Resin Composite And The Smart Damping Of Its Cantilever Structure

Syntactic foams are composite materials consisting hollow particles dispersed in a matrix material. Due to its low density, high specific strength, low radar detectivity and low moisture absorption, syntactic foams has been extensively used in aerospace, aviation applications and underwater, deep-sea buoyant material. In this paper, syntactic foam were prepared by mixing hollow glass microspheres (HGM) into epoxy resin, and their mechanical properties were tested by quasi-static uniaxial compression. In order to simulate the dispersion of hollow microsphere, a random spatial dispersing algorism was utilized. By using finite element analysis software,the stress, strain, displacement vector of syntactic foam were analyzed; the damping properties of syntactic foam cantilever are tested by INV damping calculation method; by using real-time system based on XPC Target, vibration active control of syntactic foam are tested; with different deploy strategy, PMN/CB/EP composite damper were deployed on the syntactic foam cantilever, and chirp simulation is applied to the cantilever in order to find an appropriate method to reduce the amplitude of the cantilever (time domain) and response (frequency domain) in low frequency width(0-500Hz).The following important conclusions might be drawn in this dissertation:To a certain degree, the density and wall thickness of HGM affects the mechanical and elastic properties of syntactic foam. Increasing the volume fraction of thin-walled HGM would leads to the decrease of compressive strength and modulus of syntactic foam whereas increasing the volume fraction of thick-walled HGM would increase the compressive strength and modulus of syntactic foam. With same density, Syntactic foam prepared with HGM consisting large-diameter but thin-walled HGM and small-diameter but thick-walled HGM owns higher compressive strength and modulus value then those prepared with thin-walled HGM.By analyzing the coordinates of spherical particles in the random spatial distribution models, it is found that particles are dispersed uniformly in the given space. Results of finite element analysis shows that when increasing the wall thickness of HGM, the von-Mises stress distribution changed in the syntactic foam. In syntactic foam prepared with thin-walled HGM, HGM is main energy absorber, and maximun stress is located on the inner surface of HGM, whereas in syntactic foam prepared with thick-walled HGM, maximum stress is located on the outer surface of HGM, which means matrix resin around HGM is also absorbing energy. More matrix get involved in energy absorping when increasing the wallthickness of HGM.The natural frequency and damping ratio tested with INV method shows that the damping ratio of syntactic foam cantilever increase when increase the volume fraction of HGM. But the damping ratio falls when the volume fraction of HGM increased to a certain value.The piezoelectric based active vibration control is carried out with XPC Target real time environment. The impulse harmer is used to generate an impulse to stimulus the cantilever, and the active control system could reduce the vibration to a certain extent. Active vibration control is also performed when the cantilevers are stimulated by excitation with first and second natural frequency. The result shows that the control system performance is better when controlling second mode vibration.By certain kind of deploy strategy and stimulus, PMN/CB/EP dampers could be used to reduce the vibration amplitude and structural response in a certain low frequency width.