Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techn...Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.展开更多
Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their d...Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their decomposition due to low resistance towards salinity and hence polymer composites have been explored to showcase their mechanical stability to withstand transverse and impact loads.To this end,the mechanical properties of S-Glass/carbon fiber reinforced polymer composite were experimentally investigated and higher specific strength and stiffness of the composite in comparison to many metallic materials used for submarine hull were reported.The obtained experimental values were used for the static and dynamic crash analysis of the bow,stern and foil through Finite Element Analysis(FEA);where depth of travel was varied from sea surface level of 0-7000 m.Submarine assembly was later developed with the optimum shape and thickness of each part.We also report the nonlinear crash analysis upon impact at velocity ranging from 3 to 21 m/s.Besides,kinetic energy,acceleration peak and internal energy in struck submarine revealed that travel depth 1750 m and 3500 m is recommendable,more particularly,crash safety factor of the submarine is found to be within limit when submarine encounters crash at 1750 m.展开更多
Detailed characterization of fabric reinforcements is necessary to ensure the quality of manufactured composite parts, and subsequently to prevent structural failure during service. A lack of consensus and standardiza...Detailed characterization of fabric reinforcements is necessary to ensure the quality of manufactured composite parts, and subsequently to prevent structural failure during service. A lack of consensus and standardization exists in selecting test methods for the mechanical characterization of fabrics. Moreover, in reality, during any experimentation there are sources of uncertainties which may result in inconsistencies in the interpretation of data and the comparison of different testing methods. The aim of this article is to show how simple statistical data analysis methods may be used to enhance the characterization of composite fabrics under individual and combined loading modes while accounting for inherent material/test uncertainties. Results using a typical glass non-crimp fabric (NCF) show that, statistically, there are significant differences between the warp and weft direction responses of a presumably balanced NCF under all deformation modes, with weft yarns being generally stiffer. Moreover, the statistical significance of warp-weft couplings under both simultaneous and sequential biaxial-shear loading modes became statistically evident, when compared to a pure biaxial deformation.展开更多
In this study,the effect of fiber angle on the tensile load-bearing performance and damage failure characteristics of glass composite laminates was investigated experimentally,analytically,and numerically.The glass fa...In this study,the effect of fiber angle on the tensile load-bearing performance and damage failure characteristics of glass composite laminates was investigated experimentally,analytically,and numerically.The glass fabric in the laminate was perfectly aligned along the load direction(i.e.,at 0°),offset at angles of 30°and 45°,or mixed in different directions(i.e.,0°/30°or 0°/45°).The composite laminates were fabricated using vacuum-assisted resin molding.The influence of fiber orientation angle on the mechanical properties and stiffness degradation of the laminates was studied via cyclic tensile strength tests.Furthermore,simulations have been conducted using finite element analysis and analytical approaches to evaluate the influence of fiber orientation on the mechanical performance of glass laminates.Experimental testing revealed that,although the composite laminates laid along the 0°direction exhibited the highest stiffness and strength,their structural performance deteriorated rapidly.We also determined that increasing the fiber offset angle(i.e.,30°)could optimize the mechanical properties and damage failure characteristics of glass laminates.The results of the numerical and analytical approaches demonstrated their ability to capture the mechanical behavior and damage failure modes of composite laminates with different fiber orientations,which may be used to prevent the catastrophic failures that occur in composite laminates.展开更多
The effect of delamination on the stiffness reduction of composite pipes is studied in this research.The stiffness test of filament wound composite pipes is simulated using cohesive zone method.The modeling is accompl...The effect of delamination on the stiffness reduction of composite pipes is studied in this research.The stiffness test of filament wound composite pipes is simulated using cohesive zone method.The modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite pipes.At first,finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM D2412.It is seen that the finite element results agree well with experimental results.Then the finite element model is developed for composite pips with delaminated areas with different primary shapes.Thus,the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.展开更多
Self-sensing uses the cement-based material without sensor incor-poration to sense itself.This paper reviews self-sensing cementbased materials,with coverage of the well-studied resistance-based sensing as well as the...Self-sensing uses the cement-based material without sensor incor-poration to sense itself.This paper reviews self-sensing cementbased materials,with coverage of the well-studied resistance-based sensing as well as the less-studied capacitance-based sensing.This review is the first that covers capacitance-based self-sensing.Capacitance-based sensing is advantageous over resistance-based sensing in that no particular admixture is required,so that it is applicable to both existing and new structures.In contrast,resis-tancebased sensing that is comparable to capacitance-based sen-sing in stress/strain sensitivity requires conductive admixtures,such as carbon fiber.Resistance-based strain sensing is based on piezo-resistivity,which is associated with the resistance increasing upon tension and decreasing upon compression.Capacitance-based strain sensing is based on piezopermittivity,which is associated with the permittivity decreasing upon tension and increasing upon compression.Damage causes the resistance to increase and causes the permittivity to decrease.Increase in temperature decreases the resistance but increases the permittivity.This review also covers the methodology of the electrical measurements.展开更多
A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact.Both in-plane and out-of-plane failure mo...A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact.Both in-plane and out-of-plane failure modes are taken into account simultaneously and thus all components of the stress and strain fields are derived.For this purpose,layer-wise theory is employed in a composite cylinder under internal pressure and low-velocity impact.Obtained stress/strain components are fed into appropriate failure criteria for investigating the occurrence of failure.In case of experiencing any in-plane failure mode,the evolution of damage is modeled using progressive damage modeling in the context of continuum damage mechanics.Namely,mechanical properties of failed ply are degraded and stress analysis is performed on the updated status of the model.In the event of delamination occurrence,the solution is terminated.The obtained results are validated with available experimental observations in open literature.It is observed that the sequence of in-plane failure and delamination varies by increasing the impact energy.展开更多
In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electroc...In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electrochemical,and mechanical behaviors of FEDs.The importance of flexible lithium-ion batteries(FLIBs)in the area of FEDs is evident;however,less attention has been paid to the mechanical behavior of FLIBs in comparison with the material and electrochemical characteristics.The present paper reviewed the research works in the FLIBs,focusing on their mechanical integrity and electrochemical performances.First,an introduction to FLIBs was presented,and the previous review papers published in this field were briefly introduced.Then,a detailed review of the available electrochemical and mechanical research works on FLIBs was presented.Moreover,the mechanical testing methods(tensile,compressive,indentation,fatigue,and adhesion)for the characterization of FLIBs’components,the research works on the simulation and modeling of the mechanical behavior of FLIBs,and a summary of the present situation and the future trend of research in this field were reviewed and presented.展开更多
基金financially supported by the University of Tabriz
文摘Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.
文摘Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their decomposition due to low resistance towards salinity and hence polymer composites have been explored to showcase their mechanical stability to withstand transverse and impact loads.To this end,the mechanical properties of S-Glass/carbon fiber reinforced polymer composite were experimentally investigated and higher specific strength and stiffness of the composite in comparison to many metallic materials used for submarine hull were reported.The obtained experimental values were used for the static and dynamic crash analysis of the bow,stern and foil through Finite Element Analysis(FEA);where depth of travel was varied from sea surface level of 0-7000 m.Submarine assembly was later developed with the optimum shape and thickness of each part.We also report the nonlinear crash analysis upon impact at velocity ranging from 3 to 21 m/s.Besides,kinetic energy,acceleration peak and internal energy in struck submarine revealed that travel depth 1750 m and 3500 m is recommendable,more particularly,crash safety factor of the submarine is found to be within limit when submarine encounters crash at 1750 m.
文摘Detailed characterization of fabric reinforcements is necessary to ensure the quality of manufactured composite parts, and subsequently to prevent structural failure during service. A lack of consensus and standardization exists in selecting test methods for the mechanical characterization of fabrics. Moreover, in reality, during any experimentation there are sources of uncertainties which may result in inconsistencies in the interpretation of data and the comparison of different testing methods. The aim of this article is to show how simple statistical data analysis methods may be used to enhance the characterization of composite fabrics under individual and combined loading modes while accounting for inherent material/test uncertainties. Results using a typical glass non-crimp fabric (NCF) show that, statistically, there are significant differences between the warp and weft direction responses of a presumably balanced NCF under all deformation modes, with weft yarns being generally stiffer. Moreover, the statistical significance of warp-weft couplings under both simultaneous and sequential biaxial-shear loading modes became statistically evident, when compared to a pure biaxial deformation.
文摘In this study,the effect of fiber angle on the tensile load-bearing performance and damage failure characteristics of glass composite laminates was investigated experimentally,analytically,and numerically.The glass fabric in the laminate was perfectly aligned along the load direction(i.e.,at 0°),offset at angles of 30°and 45°,or mixed in different directions(i.e.,0°/30°or 0°/45°).The composite laminates were fabricated using vacuum-assisted resin molding.The influence of fiber orientation angle on the mechanical properties and stiffness degradation of the laminates was studied via cyclic tensile strength tests.Furthermore,simulations have been conducted using finite element analysis and analytical approaches to evaluate the influence of fiber orientation on the mechanical performance of glass laminates.Experimental testing revealed that,although the composite laminates laid along the 0°direction exhibited the highest stiffness and strength,their structural performance deteriorated rapidly.We also determined that increasing the fiber offset angle(i.e.,30°)could optimize the mechanical properties and damage failure characteristics of glass laminates.The results of the numerical and analytical approaches demonstrated their ability to capture the mechanical behavior and damage failure modes of composite laminates with different fiber orientations,which may be used to prevent the catastrophic failures that occur in composite laminates.
文摘The effect of delamination on the stiffness reduction of composite pipes is studied in this research.The stiffness test of filament wound composite pipes is simulated using cohesive zone method.The modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite pipes.At first,finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM D2412.It is seen that the finite element results agree well with experimental results.Then the finite element model is developed for composite pips with delaminated areas with different primary shapes.Thus,the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.
文摘Self-sensing uses the cement-based material without sensor incor-poration to sense itself.This paper reviews self-sensing cementbased materials,with coverage of the well-studied resistance-based sensing as well as the less-studied capacitance-based sensing.This review is the first that covers capacitance-based self-sensing.Capacitance-based sensing is advantageous over resistance-based sensing in that no particular admixture is required,so that it is applicable to both existing and new structures.In contrast,resis-tancebased sensing that is comparable to capacitance-based sen-sing in stress/strain sensitivity requires conductive admixtures,such as carbon fiber.Resistance-based strain sensing is based on piezo-resistivity,which is associated with the resistance increasing upon tension and decreasing upon compression.Capacitance-based strain sensing is based on piezopermittivity,which is associated with the permittivity decreasing upon tension and increasing upon compression.Damage causes the resistance to increase and causes the permittivity to decrease.Increase in temperature decreases the resistance but increases the permittivity.This review also covers the methodology of the electrical measurements.
文摘A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact.Both in-plane and out-of-plane failure modes are taken into account simultaneously and thus all components of the stress and strain fields are derived.For this purpose,layer-wise theory is employed in a composite cylinder under internal pressure and low-velocity impact.Obtained stress/strain components are fed into appropriate failure criteria for investigating the occurrence of failure.In case of experiencing any in-plane failure mode,the evolution of damage is modeled using progressive damage modeling in the context of continuum damage mechanics.Namely,mechanical properties of failed ply are degraded and stress analysis is performed on the updated status of the model.In the event of delamination occurrence,the solution is terminated.The obtained results are validated with available experimental observations in open literature.It is observed that the sequence of in-plane failure and delamination varies by increasing the impact energy.
基金Z.X.W.would like to thank International Partnership Program of Chinese Academy of Sciences(No.121D11KYSB20190080)M.M.S.would like to thank the Iran National Science Foundation(INSF)(No.98011735).
文摘In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electrochemical,and mechanical behaviors of FEDs.The importance of flexible lithium-ion batteries(FLIBs)in the area of FEDs is evident;however,less attention has been paid to the mechanical behavior of FLIBs in comparison with the material and electrochemical characteristics.The present paper reviewed the research works in the FLIBs,focusing on their mechanical integrity and electrochemical performances.First,an introduction to FLIBs was presented,and the previous review papers published in this field were briefly introduced.Then,a detailed review of the available electrochemical and mechanical research works on FLIBs was presented.Moreover,the mechanical testing methods(tensile,compressive,indentation,fatigue,and adhesion)for the characterization of FLIBs’components,the research works on the simulation and modeling of the mechanical behavior of FLIBs,and a summary of the present situation and the future trend of research in this field were reviewed and presented.
