This article explores the drilling behavior of polymer nanocomposites reinforced by Graphene oxide/Carbon fiber using a hybrid method of Grey theory and Principal component analysis(GR-PCA).An online digital dynamomet...This article explores the drilling behavior of polymer nanocomposites reinforced by Graphene oxide/Carbon fiber using a hybrid method of Grey theory and Principal component analysis(GR-PCA).An online digital dynamometer was employed for the evaluation of Thrust Force and Torque.The image processing technique computes the delamination.Response surface methodology(RSM)considers the parameters,namely,drilling speed(S),feed rate(F),Graphene Oxide wt.%(G)in designing the experimentation array.Principal component analysis(PCA)was used to tackle the response priority weight during the combination of multiple functions.Analysis of variance(ANOVA)scrutinized the influence of parameters and intended the regression models to predict the response.GR-PCA evaluated the optimal parametric setting and remarked that feed rate acts as the most predominant factor.The higher feed rate and wt.%of G is responsible for surface damages like fiber pull-out,fiber fracture and cracks.A significant improvement in drilling responses has been obtained and also validates through confirmatory test and microstructure investigations.展开更多
The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the co...The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the corresponding compatibility equation are established to develop the cable force equation and cable displacement governing equation for suspension cables, respectively. Subsequently, the inextensible cable case is introduced. The formula of the Irvine parameter is considered and its physical interpretation as well as its relationship with the chord gravity stiffness is presented. The influences on the increment of cable force and displacement by λ2 and load ratio p′ are analyzed, respectively. Based on these assumptions and the analytical formulations, a 2000 m span suspension cable is utilized as an example to verify the proposed formulation and the responses of the relative increment of cable force and cable displacement under symmetrical and asymmetrical loads are studied and presented. In each case, the deflections resulting from elastic elongation or solely due to geometrical displacement are analyzed for the lower elastic modulus CFRP. Finally, in comparison with steel cables, the influences on the cable force equation and the governing displacement equation by span and rise span ratio are analyzed. Moreover, the influences on the static performance of suspension bridge by span and sag ratios are also analyzed. The substantive characteristics of the static performance of super span CFRP suspension bridges are clarified and the superiority and the characteristics of CFRP cable structure are demonstrated analytically.展开更多
This study presents the multifunctional characteristics of multi-walled carbon nanotube(MWCNT)/polypropylene random copolymer(PPR) composites enabled via fused filament fabrication(FFF) under monotonic and quasi-stati...This study presents the multifunctional characteristics of multi-walled carbon nanotube(MWCNT)/polypropylene random copolymer(PPR) composites enabled via fused filament fabrication(FFF) under monotonic and quasi-static cyclic compression. Utilizing in-house MWCNT-engineered PPR filament feedstocks, both bulk and cellular composites were realized. The morphological features of nanocomposites were examined via scanning electron microscopy, which reveals that MWCNTs are uniformly dispersed. The uniformly dispersed MWCNTs forms an electrically conductive network within the PPR matrix, and the resulting nanocomposite shows good electrical conductivity(~10^(-1)S/cm), improved mechanical performance(modulus increases by 125% and compressive strength increases by 25% for 8 wt% MWCNT loading) and pronounced piezoresistive response(gauge factor of 27.9-8.5 for bulk samples)under compression. The influence of strain rate on the piezoresistive response of bulk samples(4 wt% of MWCNT) under compression was also measured. Under repeated cyclic compression(2% constant strain amplitude), the nanocomposite exhibited stable piezoresistive performance up to 100 cycles. The piezoresistive response under repeated cyclic loading with increasing strain amplitude of was also assessed.The gauge factor of BCC and FCC cellular composites(4 wt% of MWCNT) with a relative density of 30%was observed to be 46.4 and 30.2 respectively, under compression. The higher sensitivity of the BCC plate-lattice could be attributed to its higher degree of stretching-dominated deformation behavior than the FCC plate-lattice, which exhibits bending-dominated behavior. The 3D printed cellular PPR/MWCNT composites structures were found to show excellent piezoresistive self-sensing characteristics and open new avenues for in situ structural health monitoring in various applications.展开更多
Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the ...Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair technique.Damage evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]s.Quasi Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection technique.Damaged laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged hole.Four different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI test.The results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine laminates.Patches of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine laminates.Furthermore,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.展开更多
文摘This article explores the drilling behavior of polymer nanocomposites reinforced by Graphene oxide/Carbon fiber using a hybrid method of Grey theory and Principal component analysis(GR-PCA).An online digital dynamometer was employed for the evaluation of Thrust Force and Torque.The image processing technique computes the delamination.Response surface methodology(RSM)considers the parameters,namely,drilling speed(S),feed rate(F),Graphene Oxide wt.%(G)in designing the experimentation array.Principal component analysis(PCA)was used to tackle the response priority weight during the combination of multiple functions.Analysis of variance(ANOVA)scrutinized the influence of parameters and intended the regression models to predict the response.GR-PCA evaluated the optimal parametric setting and remarked that feed rate acts as the most predominant factor.The higher feed rate and wt.%of G is responsible for surface damages like fiber pull-out,fiber fracture and cracks.A significant improvement in drilling responses has been obtained and also validates through confirmatory test and microstructure investigations.
基金Project(2010-K2-8)supported by Science and Technology Program of the Ministry of Housing and Urban Rural Development,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the corresponding compatibility equation are established to develop the cable force equation and cable displacement governing equation for suspension cables, respectively. Subsequently, the inextensible cable case is introduced. The formula of the Irvine parameter is considered and its physical interpretation as well as its relationship with the chord gravity stiffness is presented. The influences on the increment of cable force and displacement by λ2 and load ratio p′ are analyzed, respectively. Based on these assumptions and the analytical formulations, a 2000 m span suspension cable is utilized as an example to verify the proposed formulation and the responses of the relative increment of cable force and cable displacement under symmetrical and asymmetrical loads are studied and presented. In each case, the deflections resulting from elastic elongation or solely due to geometrical displacement are analyzed for the lower elastic modulus CFRP. Finally, in comparison with steel cables, the influences on the cable force equation and the governing displacement equation by span and rise span ratio are analyzed. Moreover, the influences on the static performance of suspension bridge by span and sag ratios are also analyzed. The substantive characteristics of the static performance of super span CFRP suspension bridges are clarified and the superiority and the characteristics of CFRP cable structure are demonstrated analytically.
基金financial support from the Abu Dhabi National Oil Company (ADNOC), United Arab Emirates under Award No: EX2016-000010。
文摘This study presents the multifunctional characteristics of multi-walled carbon nanotube(MWCNT)/polypropylene random copolymer(PPR) composites enabled via fused filament fabrication(FFF) under monotonic and quasi-static cyclic compression. Utilizing in-house MWCNT-engineered PPR filament feedstocks, both bulk and cellular composites were realized. The morphological features of nanocomposites were examined via scanning electron microscopy, which reveals that MWCNTs are uniformly dispersed. The uniformly dispersed MWCNTs forms an electrically conductive network within the PPR matrix, and the resulting nanocomposite shows good electrical conductivity(~10^(-1)S/cm), improved mechanical performance(modulus increases by 125% and compressive strength increases by 25% for 8 wt% MWCNT loading) and pronounced piezoresistive response(gauge factor of 27.9-8.5 for bulk samples)under compression. The influence of strain rate on the piezoresistive response of bulk samples(4 wt% of MWCNT) under compression was also measured. Under repeated cyclic compression(2% constant strain amplitude), the nanocomposite exhibited stable piezoresistive performance up to 100 cycles. The piezoresistive response under repeated cyclic loading with increasing strain amplitude of was also assessed.The gauge factor of BCC and FCC cellular composites(4 wt% of MWCNT) with a relative density of 30%was observed to be 46.4 and 30.2 respectively, under compression. The higher sensitivity of the BCC plate-lattice could be attributed to its higher degree of stretching-dominated deformation behavior than the FCC plate-lattice, which exhibits bending-dominated behavior. The 3D printed cellular PPR/MWCNT composites structures were found to show excellent piezoresistive self-sensing characteristics and open new avenues for in situ structural health monitoring in various applications.
基金the financial support by the Council of Scientific&Industrial Research(CSIR)-Research Scheme,India(22/0809/2019-EMR-II)。
文摘Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair technique.Damage evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]s.Quasi Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection technique.Damaged laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged hole.Four different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI test.The results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine laminates.Patches of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine laminates.Furthermore,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.
