The Viscoelastic Research On Hollow Glass Beads/Epoxy Resin Composite

For engineering applications,the study of the viscoelastic properties of the hollow glass microbeads/epoxy resin composites is very important.The viscoelastic properties contain the rate sensitivity,relaxation and damping.In this paper,the viscoelastic properties of HGM/EP composite under static load and dynamic load were systematically studied by experiment.The influence of temperature,strain rate and time(frequency)was analyzed,and corresponding viscoelastic models were established.The effect of particle size and volume fraction of hollow glass beads on the viscoelastic properties of composite was discussed.The interface between resin matrix and hollow glass beads directly affects the mechanical properties of the composites.The mechanical properties of the interface were predicted by numerical simulation.A quasi-static compression test was carried out by fatigue testing machine.The stress strain curves of HGM/EP composites at different strain rates and different temperatures were obtained.The effects of particle size and volume fraction of the hollow bead on the density,compressive modulus of elasticity and compressive strength were analyzed.At the same time the effects of strain rate and temperature were discussed.Based on the experimental data,the compression constitutive relation containing the strain rate and the temperature was fitted,and the Sherwood-Frost constitutive model was modified.The results show that the small size hollow glass bead can improve the compression strength,and the compression performance of the material shows a significant dependence on the temperature and strain rate.The three point bending test was carried out by a microforce tester.The effects of different content of hollow glass bead,different content of glass fiber and interface corrosion damage on the flexural properties of the composites were studied.The quasi-static compression relaxation behavior of HGM/EP composites was tested.The Wiechert model describing the stress relaxation of resin at different temperatures was established.The effect of the volume fraction and particle size of the hollow glass bead on the relaxation behavior of the composites was analyzed,and the stress relaxation mechanism was discussed.The expression of equivalent relaxation modulus was calculated by microscopic homogenization,and the viscoelastic model of composite was established based on experimental data.According to the experimental data,the relaxation modulus was fitted to the form of Prony series,and the creep flexibility was solved,and the creep properties of HGM/EP composites with different volume fraction were predicted.The fractional derivative model can be used to describe the viscoelastic behavior of HGM/EP composites with fewer parameters,and the fitting parameters have certain physical meaning.By dynamic mechanical analysis of HGM/EP composites(DMA),the dynamic mechanical temperature spectrum of the matrix material at different frequencies was given.By using the time temperature equivalent principle,the main frequency curves of storage modulus and loss modulus at room temperature were constructed according to the displacement factors.The effects of temperature and frequency,volume fraction and particle size on the storage modulus and loss modulus were analyzed,and the mechanism was analyzed by scanning electron microscope.The loss factor and the glass transition temperature with the volume fraction and frequency were compared.The bonding condition of the interface was evaluated through the interaction parameters of the filler and matrix.The influence mechanism of the damping was analyzed.The results show that the ratio of 10% is beneficial to improve its dynamic mechanical properties.The agglomeration and interfacial adhesion of the particles have a great influence on the dynamic mechanical properties of the composites.The elastic model of ideal interface is not suitable for HGM/EP composites with high volume fraction.The mechanical behavior of HGM/EP composites was predicted effectively by simulating the interface between the matrix and the glass bead,and the influence of the interface thickness and strength on the mechanical properties of the composites was analyzed.By comparing with the experimental data,the prediction results of the interface reflect the weak bonding state of the interface between microsphere and matrix,and the effect of the interfacial properties on the macroscopic mechanical properties of the material was verified.When the interface between the particles and the matrix is weak,the debonding is easy to occur,resulting in the decrease of overall strength Then the redistribution of internal stress and the evolution of damage directly affect the mechanical properties of materials.