الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.In aerospace applications research efforts are focusing on the design of advanced composite materials reinforced with nanofillers. Such advanced materials combine weight saving with multifunctional properties, including mechanical and tribological ones. In the present investigation, multiwall carbon nanotubes (MWCNTs) and alumina (Al2O3) nanoparticles were dispersed individually by different weight percentages into epoxy-based polymeric nanocomposites. MWCNTs of 20 and 30 nm inner and outer diameters and Al2O3 of 10 nm diameter were reinforced by contents of 0.25, 0.5, 0.75 and 1 wt. % into epoxy matrix.
Mechanical properties of Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites such as Vickers microhardness, tensile strength, strain at break, impact energy and bending strength and were examined. Moreover, the Scanning electron microscopy (SEM) of the worn surfaces after tensile and bending tests were examined. Tribological characteristics including coefficients of friction (COF) and wear rates were measured for the two nanocomposites, also SEM was used to examine the worn surfaces after the wear tests. A pin-on-ring apparatus was used under dry sliding conditions at different applied loads and sliding speeds.
The design was done using using mixed full factorial design of experiments (DOE). Minitab software was applied to study the effect of the test parameters on COF and wear rate. While analysis of variance (ANOVA) used to perform the analysis. Free vibration test was performed to examine the dynamic behaviours such as frequency responses and damping ratios for Epoxy/MWCNTs and Epoxy/Al2O3 nanocomposites.
xix
The mechanical tests results revealed declining in tensile strength, strain at break and impact energy. While the bending strength and microhardness values increased with addition of nanofillers into the epoxy matrix. The tribological results demonstrated that the COF and wear rate were enhanced by the homogeneous dispersion of the nanofillers into the epoxy resin. Increasing the MWCNTs weight percent reduces the COF and wear rate of the nanocomposite, while the reduction of COF and wear rate with addition of Al2O3 nanoparticles was achieved only at small amounts. The Epoxy/MWCNTs nanocomposites at 1wt % showed lower COF and wear rate when compared with Epoxy/Al2O3 nanocomposites due its self-lubricating property.
Frequency response and damping factor was strongly affected by the weight percent of the nanofillers. The damping factor has the same down trend with the mechanical properties of the nanocomposites. The results also demonstrated that, the natural frequency of nanocomposites was increased by increasing the weight percent of nanofillers.