Quasi-static and dynamic mechanical properties of glass-fiber reinforced polymer composites embedded with and without tetraneedle-shaped ZnO whiskers(T-ZnOw)in two loading directions are investigated by a split Hopkin...Quasi-static and dynamic mechanical properties of glass-fiber reinforced polymer composites embedded with and without tetraneedle-shaped ZnO whiskers(T-ZnOw)in two loading directions are investigated by a split Hopkinson pressure bar.The stress-strain curves,ultimate strength,failure strain and elastic modulus are obtained and the failure mechanism of the composites is investigated by a high-speed camera and a scanning electron microscope.Strain rate effects on the mechanical behavior are discussed and the corresponding models are derived by fitting the experimental data.The experimental results show that the composites with T-ZnOw under dynamic loading have multiple failure modes and better mechanical properties.Finally,the strengthening and toughening mechanisms of T-ZnOw are analyzed.It is shown that T-ZnOw can improve mechanical properties of the composites,and can make the composites have some new features.The present results provide a reliable basis for advanced composite design and manufacture,and have broad applications in the field of aerospace.展开更多
The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at hig...The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.展开更多
We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2)...We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2) inorganic systems,the twin−percolation phenomenon exists when the concentrations of MWCNTs are 5–10%and 15–20%.The permittivity and conductivity have jumping changes.The twin−percolation phenomenon is attributed to the special transfer mechanism of MWCNTs in the system,determined by hopping and migrating electrons.Variations of dielectric properties and conductance of the MWCNTs/SiO_(2) systems are conformed to the percolation theory.The special percolation phenomenon and electric properties of MWCNTs/SiO_(2) can help us comprehend the conductivity mechanism of the MWCNTs/SiO2 systems effectively,and promote the development of a high performance function composite system.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10672020 and 50742007.
文摘Quasi-static and dynamic mechanical properties of glass-fiber reinforced polymer composites embedded with and without tetraneedle-shaped ZnO whiskers(T-ZnOw)in two loading directions are investigated by a split Hopkinson pressure bar.The stress-strain curves,ultimate strength,failure strain and elastic modulus are obtained and the failure mechanism of the composites is investigated by a high-speed camera and a scanning electron microscope.Strain rate effects on the mechanical behavior are discussed and the corresponding models are derived by fitting the experimental data.The experimental results show that the composites with T-ZnOw under dynamic loading have multiple failure modes and better mechanical properties.Finally,the strengthening and toughening mechanisms of T-ZnOw are analyzed.It is shown that T-ZnOw can improve mechanical properties of the composites,and can make the composites have some new features.The present results provide a reliable basis for advanced composite design and manufacture,and have broad applications in the field of aerospace.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50872159,50972014,51072024 and 51132002.
文摘The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.
基金Supported by the National Natural Science Foundation of China under Grant Nos.50872159,50972014 and 51072024.
文摘We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2) inorganic systems,the twin−percolation phenomenon exists when the concentrations of MWCNTs are 5–10%and 15–20%.The permittivity and conductivity have jumping changes.The twin−percolation phenomenon is attributed to the special transfer mechanism of MWCNTs in the system,determined by hopping and migrating electrons.Variations of dielectric properties and conductance of the MWCNTs/SiO_(2) systems are conformed to the percolation theory.The special percolation phenomenon and electric properties of MWCNTs/SiO_(2) can help us comprehend the conductivity mechanism of the MWCNTs/SiO2 systems effectively,and promote the development of a high performance function composite system.
