Transactions of Nanjing University of Aeronautics & Astronautics
Issue S1,2023 Table of Contents
2023(S1):1-12.
DOI: 10.16356/j.1005-1120.2023.S1.001
Abstract:
The distribution of ice cloud parameters is of great significance to the analysis of aircraft icing. In order to obtain these parameters， traditional high-fidelity numerical simulation techniques have low computational efficiency and are difficult to apply in engineering scenarios that require real-time evaluation of icing. To overcome this difficulty， a non-intrusive surrogate model is proposed by proper orthogonal decomposion （POD） model coupled with the Kriging technology. The model takes four flight parameters and two cloud parameters as input variables. The model outputs are liquid water content（LWC） and droplet collection efficiency. A quasi-three-dimensional NACA0012 airfoil is adopted to verify the accuracy and computational efficiency of the model. The numerical results of the four test cases show that the POD_Kriging model is able to produce satisfactory results for the statistical quantities of interest. It is found that the developed surrogate model is computationally more efficient than the classical FENSAP-ICE for simulation of icing cloud field.
The distribution of ice cloud parameters is of great significance to the analysis of aircraft icing. In order to obtain these parameters， traditional high-fidelity numerical simulation techniques have low computational efficiency and are difficult to apply in engineering scenarios that require real-time evaluation of icing. To overcome this difficulty， a non-intrusive surrogate model is proposed by proper orthogonal decomposion （POD） model coupled with the Kriging technology. The model takes four flight parameters and two cloud parameters as input variables. The model outputs are liquid water content（LWC） and droplet collection efficiency. A quasi-three-dimensional NACA0012 airfoil is adopted to verify the accuracy and computational efficiency of the model. The numerical results of the four test cases show that the POD_Kriging model is able to produce satisfactory results for the statistical quantities of interest. It is found that the developed surrogate model is computationally more efficient than the classical FENSAP-ICE for simulation of icing cloud field.
2 Numerical Study on Dynamic Behavior of Non-Newtonian De-icing Liquid Film Impacted by Water Droplets
2023(S1):13-28.
DOI: 10.16356/j.1005-1120.2023.S1.002
Abstract:
In freezing rainy weather， physical processes， such as sputtering， spreading， and miscibility， will occur after the supercooled large water droplets hit the liquid film of the de-icing liquid， the temperature and concentration of the liquid film of the de-icing liquid will decrease， the freezing point of the liquid film will rise and the viscosity will decrease， causing the liquid film to slide and detach and greatly shortening the anti-icing holding time. Based on the volume of fluid （VOF） method and combined with the component transport equation， a dynamic behavior model of multi-phase， multi-component， multi-system， multi-field coupled water droplet hitting non-Newtonian de-icing liquid film is constructed. Based on this numerical model， the kinetic behavior of water droplet hitting the unsteady state process and the non-Newtonian rheological characteristics， such as dilution and viscosity reduction of liquid film， are studied. The results show that the higher the initial concentration of the liquid film， the greater the degree of inhibition of the growth of the water droplet crown， the smaller the spreading diameter of the water droplet after impact， the more obvious the water transport migration phenomenon in the collision area of the water droplet and the de-icing liquid film， and the more obvious the viscosity decrease of the de-icing liquid film under the coupling effect of shear dilution and concentration reduction. The larger the initial diameter of the water droplet， the larger the range of the water droplet on the liquid film， and the greater the decrease in the viscosity of the liquid film. The greater the falling impact speed of the water droplet， the faster the migration rate of the components of the water droplet in the liquid film， and the more obvious the viscosity loss of the liquid film.
In freezing rainy weather， physical processes， such as sputtering， spreading， and miscibility， will occur after the supercooled large water droplets hit the liquid film of the de-icing liquid， the temperature and concentration of the liquid film of the de-icing liquid will decrease， the freezing point of the liquid film will rise and the viscosity will decrease， causing the liquid film to slide and detach and greatly shortening the anti-icing holding time. Based on the volume of fluid （VOF） method and combined with the component transport equation， a dynamic behavior model of multi-phase， multi-component， multi-system， multi-field coupled water droplet hitting non-Newtonian de-icing liquid film is constructed. Based on this numerical model， the kinetic behavior of water droplet hitting the unsteady state process and the non-Newtonian rheological characteristics， such as dilution and viscosity reduction of liquid film， are studied. The results show that the higher the initial concentration of the liquid film， the greater the degree of inhibition of the growth of the water droplet crown， the smaller the spreading diameter of the water droplet after impact， the more obvious the water transport migration phenomenon in the collision area of the water droplet and the de-icing liquid film， and the more obvious the viscosity decrease of the de-icing liquid film under the coupling effect of shear dilution and concentration reduction. The larger the initial diameter of the water droplet， the larger the range of the water droplet on the liquid film， and the greater the decrease in the viscosity of the liquid film. The greater the falling impact speed of the water droplet， the faster the migration rate of the components of the water droplet in the liquid film， and the more obvious the viscosity loss of the liquid film.
3 Numerical Simulation of Pantograph-Catenary Coupling De-icing Based on Orthogonal Experiment Method
2023(S1):29-41.
DOI: 10.16356/j.1005-1120.2023.S1.003
Abstract:
An investigation was conducted to examine the impact of the operating speed， ice thickness， pantograph head mass， pantograph head stiffness， and pantograph head damping on the de-icing rate. The investigation utilized the orthogonal experimental method and finite element simulation， employing a five-factor four-level orthogonal experimental design. Finite element models（FEM） were utilized to establish models for the ice-coating of the overhead contact system （OCS） and the coupling of the pantograph and catenary （PAC）. The accuracy of the FEM was subsequently validated through a comparison between theoretical values and simulation results. The simulation results show that the operating speed and pantograph head mass have a significant impact on the contact force and contact wire lift amount， which in turn affects the de-icing rate. However， the influence of the pantograph head mass becomes less significant when it exceeds 17 kg. The results of the orthogonal experiment suggest that the de-icing rate is primarily influenced by the train speed， pantograph head mass， and ice thickness. The effects of pantograph head stiffness and damping are deemed insignificant. These results can provide references for improving train operation safety and PAC coupling de-icing technology.
An investigation was conducted to examine the impact of the operating speed， ice thickness， pantograph head mass， pantograph head stiffness， and pantograph head damping on the de-icing rate. The investigation utilized the orthogonal experimental method and finite element simulation， employing a five-factor four-level orthogonal experimental design. Finite element models（FEM） were utilized to establish models for the ice-coating of the overhead contact system （OCS） and the coupling of the pantograph and catenary （PAC）. The accuracy of the FEM was subsequently validated through a comparison between theoretical values and simulation results. The simulation results show that the operating speed and pantograph head mass have a significant impact on the contact force and contact wire lift amount， which in turn affects the de-icing rate. However， the influence of the pantograph head mass becomes less significant when it exceeds 17 kg. The results of the orthogonal experiment suggest that the de-icing rate is primarily influenced by the train speed， pantograph head mass， and ice thickness. The effects of pantograph head stiffness and damping are deemed insignificant. These results can provide references for improving train operation safety and PAC coupling de-icing technology.
2023(S1):42-49.
DOI: 10.16356/j.1005-1120.2023.S1.004
Abstract:
It is of great significance to optimize de-icing methods by studying the adhesion characteristics between icing and object surfaces， as well as mastering the separation process between them. Although nano-scale numerical simulations provide some insights into the icing separation process， they fail to fully capture the complexities of real-world icing phenomena. Hence， there is a need to investigate the macro-scale icing separation process. We have constructed a test bench capable of assessing icing adhesion in both the normal and tangential directions. By conducting experiments at different temperatures， we have obtained valuable data on the change in normal and tangential adhesion between icing icicles and metal surfaces. Moreover， we have introduced a macroscopic icing adhesion model and incorporated a constitutive model for the cohesion unit layer. This facilitates the numerical simulation of the separation process between icing and metal surfaces in Abaqus software. By validating simulation results with experimental data， we gain insights into the characteristics of icing adhesion and achieve a better understanding of the icing and metal sheet separation process.
It is of great significance to optimize de-icing methods by studying the adhesion characteristics between icing and object surfaces， as well as mastering the separation process between them. Although nano-scale numerical simulations provide some insights into the icing separation process， they fail to fully capture the complexities of real-world icing phenomena. Hence， there is a need to investigate the macro-scale icing separation process. We have constructed a test bench capable of assessing icing adhesion in both the normal and tangential directions. By conducting experiments at different temperatures， we have obtained valuable data on the change in normal and tangential adhesion between icing icicles and metal surfaces. Moreover， we have introduced a macroscopic icing adhesion model and incorporated a constitutive model for the cohesion unit layer. This facilitates the numerical simulation of the separation process between icing and metal surfaces in Abaqus software. By validating simulation results with experimental data， we gain insights into the characteristics of icing adhesion and achieve a better understanding of the icing and metal sheet separation process.
5 Simulation of Aircraft Electro-Thermal Windshield Heat Transfer with Artificial Heat Source Method
2023(S1):50-54.
DOI: 10.16356/j.1005-1120.2023.S1.005
Abstract:
An artificial heat source（AHS） method is proposed to solve the problem of negative volume or non-physical property errors that happens in the process of heat transfer simulation of the aircraft electro-thermal windshield which has a thin film heater embodied in its multilayer structure. Since the thickness of the thin film heater is very small （10-9—10-7 m），the temperature gradient between the film heaters and the time delay generated by heating the film heater can be ignored， and the thermal diffusivity can be set to infinity for decoupling the thickness relationship between the real heat source and the mesh model in the simulation. Heat transfer simulations are conducted on the aircraft electro-thermal windshield mesh models with different thicknesses of the film heater. The results show that with the AHS method， mesh thicknesses of the thin film heater has no influence on the results of the simulation， and the problem of negative volume or non-physical property errors is solved spontaneously.
An artificial heat source（AHS） method is proposed to solve the problem of negative volume or non-physical property errors that happens in the process of heat transfer simulation of the aircraft electro-thermal windshield which has a thin film heater embodied in its multilayer structure. Since the thickness of the thin film heater is very small （10-9—10-7 m），the temperature gradient between the film heaters and the time delay generated by heating the film heater can be ignored， and the thermal diffusivity can be set to infinity for decoupling the thickness relationship between the real heat source and the mesh model in the simulation. Heat transfer simulations are conducted on the aircraft electro-thermal windshield mesh models with different thicknesses of the film heater. The results show that with the AHS method， mesh thicknesses of the thin film heater has no influence on the results of the simulation， and the problem of negative volume or non-physical property errors is solved spontaneously.
2023(S1):55-65.
DOI: 10.16356/j.1005-1120.2023.S1.006
Abstract:
Aircraft propellers may encounter various harsh environments due to regional differences and weather changes during their service. Therefore， ideal rubber composites for aircraft propellers must have excellent superhydrophobic properties， delayed icing performance and environmental durability. In this paper， the silicone rubber superhydrophobic surface was prepared via the template method and high temperature treatment. The effects of low-temperature freezing， high-temperature heating and UV irradiation on the hydrophobic properties of superhydrophobic silicone rubber were investigated. In addition， the self-assembled delayed icing device was implemented to reveal the delayed freezing behavior of the superhydrophobic silicone rubber under the influence of moisture in the air. Scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS） were employed to elucidate changes in superhydrophobic properties and delayed freezing mechanisms. The results show that the as-prepared superhydrophobic silicone rubber has demonstrated remarkable environmental durability and delayed freezing performance. It has important practical application value in superhydrophobic electric heating anti-icing of aircraft propeller.
Aircraft propellers may encounter various harsh environments due to regional differences and weather changes during their service. Therefore， ideal rubber composites for aircraft propellers must have excellent superhydrophobic properties， delayed icing performance and environmental durability. In this paper， the silicone rubber superhydrophobic surface was prepared via the template method and high temperature treatment. The effects of low-temperature freezing， high-temperature heating and UV irradiation on the hydrophobic properties of superhydrophobic silicone rubber were investigated. In addition， the self-assembled delayed icing device was implemented to reveal the delayed freezing behavior of the superhydrophobic silicone rubber under the influence of moisture in the air. Scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS） were employed to elucidate changes in superhydrophobic properties and delayed freezing mechanisms. The results show that the as-prepared superhydrophobic silicone rubber has demonstrated remarkable environmental durability and delayed freezing performance. It has important practical application value in superhydrophobic electric heating anti-icing of aircraft propeller.
2023(S1):66-83.
DOI: 10.16356/j.1005-1120.2023.S1.007
Abstract:
Suppression of ice formation by inhibiting droplet deposition from both passive surface functionalization and active application of ultrasonic vibration is investigated through numerical simulation and experiments. The contact time of droplet impacting on superhydrophobic surfaces with macro-structures， including cubic protrusion， single and crossed triangular ridges， and suspended prism， can be effectively reduced due to the droplet deformation induced by the structures during expansion and retraction processes. The substrate subjected to ultrasonic vibration exhibits a nonlinear distribution of equivalent shear stress， which leads to different dynamics modes of impact droplet and iced droplet removal performance. This work reveals the effectiveness of macro-structures and the ultrasonic vibration on anti-icing and de-icing， and provides potential approaches for the design and optimization of anti-/de-icing system.
Suppression of ice formation by inhibiting droplet deposition from both passive surface functionalization and active application of ultrasonic vibration is investigated through numerical simulation and experiments. The contact time of droplet impacting on superhydrophobic surfaces with macro-structures， including cubic protrusion， single and crossed triangular ridges， and suspended prism， can be effectively reduced due to the droplet deformation induced by the structures during expansion and retraction processes. The substrate subjected to ultrasonic vibration exhibits a nonlinear distribution of equivalent shear stress， which leads to different dynamics modes of impact droplet and iced droplet removal performance. This work reveals the effectiveness of macro-structures and the ultrasonic vibration on anti-icing and de-icing， and provides potential approaches for the design and optimization of anti-/de-icing system.
2023(S1):84-95.
DOI: 10.16356/j.1005-1120.2023.S1.008
Abstract:
Ice protection technology based on the mechanical vibration of piezoelectric actuators is a new lightweight and energy-efficient de-icing method. It is gaining increasing interest for use in aviation to mitigate ice-related hazards. The investigation of mechanical vibration de-icing technology encompasses two primary aspects： interface shear stress induced by mechanical vibration and corresponding vibration modes. Finding proper vibration modes to generate enough interface shear stress for de-icing efficiency improvement is a challenge. The vibration mode of the plate is often described by the values m and n， while m and n are the number of anti-nodes in the transversal axis and longitudinal axis separately. This paper is to investigate the distribution characteristics of de-icing shear stress and related vibration parameters （m and n） under different structural vibration modes， so as to establish the structure mode selection criteria for the detail designing process of the mechanical vibration-based ice protection system （IPS）. The relationship between interface shear stress and vibration mode parameters under the single force excitation is established by theoretical analysis and simulation methods. A finite element model （FEM）， depicting an aluminum plate with an ice layer attached to its surface， is used to simulate the stress-strain levels of the whole structure. According to the simulation outcomes and experimental verification， the distribution characteristics of de-icing parameters are analyzed. The selection of the initial de-icing modes based on the characteristics of m and n values of the flexural vibration modes is emphasized.
Ice protection technology based on the mechanical vibration of piezoelectric actuators is a new lightweight and energy-efficient de-icing method. It is gaining increasing interest for use in aviation to mitigate ice-related hazards. The investigation of mechanical vibration de-icing technology encompasses two primary aspects： interface shear stress induced by mechanical vibration and corresponding vibration modes. Finding proper vibration modes to generate enough interface shear stress for de-icing efficiency improvement is a challenge. The vibration mode of the plate is often described by the values m and n， while m and n are the number of anti-nodes in the transversal axis and longitudinal axis separately. This paper is to investigate the distribution characteristics of de-icing shear stress and related vibration parameters （m and n） under different structural vibration modes， so as to establish the structure mode selection criteria for the detail designing process of the mechanical vibration-based ice protection system （IPS）. The relationship between interface shear stress and vibration mode parameters under the single force excitation is established by theoretical analysis and simulation methods. A finite element model （FEM）， depicting an aluminum plate with an ice layer attached to its surface， is used to simulate the stress-strain levels of the whole structure. According to the simulation outcomes and experimental verification， the distribution characteristics of de-icing parameters are analyzed. The selection of the initial de-icing modes based on the characteristics of m and n values of the flexural vibration modes is emphasized.
2023(S1):96-104.
DOI: 10.16356/j.1005-1120.2023.S1.009
Abstract:
Innovative development of an anti- and de-icing system which can be practically used for aircraft wings is an ongoing challenge. High energy-consumption of electrothermal anti-icing/de-icing in aircraft is a tough problem up to date. In this work， we design an anti/de-icing structure based on the electric heating. The electrothermal structure is composed of the polydimethylsiloxane （PDMS） insulation coating， conductive layer， electrothermal layer and porous insulation layer from the top to the bottom. The effect of the thickness of the conductive silver paste layer and the content of the conductive liquid on the temperature of the insulation layer and the insulation layer under different power levels is investigated. The results indicate that at room temperature， when the input power is 4 W and the thickness of the silver slurry layer is 300 μm， the maximum temperature of the insulation layer can reach 134 ℃. Moreover， when the input power is 18 W， the top temperature can quickly reach 0 ℃， while the bottom temperature remains around -12.5 ℃ at -20 ℃， resulting in less energy loss. Our study can provide theoretical guidance for the design of electric heating anti-icing material systems.
Innovative development of an anti- and de-icing system which can be practically used for aircraft wings is an ongoing challenge. High energy-consumption of electrothermal anti-icing/de-icing in aircraft is a tough problem up to date. In this work， we design an anti/de-icing structure based on the electric heating. The electrothermal structure is composed of the polydimethylsiloxane （PDMS） insulation coating， conductive layer， electrothermal layer and porous insulation layer from the top to the bottom. The effect of the thickness of the conductive silver paste layer and the content of the conductive liquid on the temperature of the insulation layer and the insulation layer under different power levels is investigated. The results indicate that at room temperature， when the input power is 4 W and the thickness of the silver slurry layer is 300 μm， the maximum temperature of the insulation layer can reach 134 ℃. Moreover， when the input power is 18 W， the top temperature can quickly reach 0 ℃， while the bottom temperature remains around -12.5 ℃ at -20 ℃， resulting in less energy loss. Our study can provide theoretical guidance for the design of electric heating anti-icing material systems.
2023(S1):105-117.
DOI: 10.16356/j.1005-1120.2023.S1.010
Abstract:
Ice detection plays a crucial role in operation of anti/de-icing systems. An ice detection method exploiting infrared thermal wave detection technology was proposed， followed by the identification of the edge， thickness and shape reconstruction of ice accretion using the related processing techniques. An active infrared ice detection experimental platform was constructed by flash pulse infrared technology. With regular and step-shaped ice samples prepared， the infrared thermal signals of the ice accretion were captured by an infrared thermal imager. A comparative analysis of the edge detection effects was conducted between the traditional edge detection methods and a new edge detection algorithm combining Gaussian-Laplacian pyramids and area filtering. Through the spatiotemporal correlation of the ice thermal signal， an end-to-end infrared detection ice thickness prediction model （i.e.， convolutional neural network-long short term memory-efficient channel attention （CNN-LSTM-ECA）） was constructed by introducing the attention mechanism into the LSTM model， with the thickness of the ice predicted. Further， three-dimensional reconstruction of ice accretion was performed by combining the edge detection and thickness prediction. It concluded that both traditional and new edge detection algorithms based on Gaussian-Laplacian pyramids and area filtering can be used to detect the outer edge of the ice， but the new algorithm shows a significant advantage in detecting the ice edge with internal step boundaries. The CNN-LSTM-ECA thickness prediction model based on signal features performs well in prediction accuracy， stability， and noise resistance. The data for reconstructing three-dimensional ice accretion shape come from the collected digital signals and thermal images， which are not limited by temperature reading and heat transfer conditions， and have a wider application prospect. This paper provides a reference for exploring an effective accurate and quantitative identification method for ice accretion detection based on flash pulse infrared thermography.
Ice detection plays a crucial role in operation of anti/de-icing systems. An ice detection method exploiting infrared thermal wave detection technology was proposed， followed by the identification of the edge， thickness and shape reconstruction of ice accretion using the related processing techniques. An active infrared ice detection experimental platform was constructed by flash pulse infrared technology. With regular and step-shaped ice samples prepared， the infrared thermal signals of the ice accretion were captured by an infrared thermal imager. A comparative analysis of the edge detection effects was conducted between the traditional edge detection methods and a new edge detection algorithm combining Gaussian-Laplacian pyramids and area filtering. Through the spatiotemporal correlation of the ice thermal signal， an end-to-end infrared detection ice thickness prediction model （i.e.， convolutional neural network-long short term memory-efficient channel attention （CNN-LSTM-ECA）） was constructed by introducing the attention mechanism into the LSTM model， with the thickness of the ice predicted. Further， three-dimensional reconstruction of ice accretion was performed by combining the edge detection and thickness prediction. It concluded that both traditional and new edge detection algorithms based on Gaussian-Laplacian pyramids and area filtering can be used to detect the outer edge of the ice， but the new algorithm shows a significant advantage in detecting the ice edge with internal step boundaries. The CNN-LSTM-ECA thickness prediction model based on signal features performs well in prediction accuracy， stability， and noise resistance. The data for reconstructing three-dimensional ice accretion shape come from the collected digital signals and thermal images， which are not limited by temperature reading and heat transfer conditions， and have a wider application prospect. This paper provides a reference for exploring an effective accurate and quantitative identification method for ice accretion detection based on flash pulse infrared thermography.
2023(S1):118-128.
DOI: 10.16356/j.1005-1120.2023.S1.011
Abstract:
In order to cope with the problem of ice porosity measurement in aircraft icing scenarios， an ultrasonic porosity measurement method based on dynamic wavelet fingerprint technology is proposed and evaluated. The propagation process of ultrasonic longitudinal waves is analyzed by theoretical model and finite element simulation， and the mechanism of the influence of pore size and other factors on porosity measurement is illustrated. Combined with 60 sets of ultrasonic measurement data of 20 ice samples， wavelet fingerprint images are generated， and 11-D key features are extracted. Based on the principal component analysis and polynomial fitting， the realized porosity measurement root mean square error （RMSE） reached 1.144%， which shows the proposed method is more stable and accurate than the traditional peak fitting method.
In order to cope with the problem of ice porosity measurement in aircraft icing scenarios， an ultrasonic porosity measurement method based on dynamic wavelet fingerprint technology is proposed and evaluated. The propagation process of ultrasonic longitudinal waves is analyzed by theoretical model and finite element simulation， and the mechanism of the influence of pore size and other factors on porosity measurement is illustrated. Combined with 60 sets of ultrasonic measurement data of 20 ice samples， wavelet fingerprint images are generated， and 11-D key features are extracted. Based on the principal component analysis and polynomial fitting， the realized porosity measurement root mean square error （RMSE） reached 1.144%， which shows the proposed method is more stable and accurate than the traditional peak fitting method.
2023(S1):129-137.
DOI: 10.16356/j.1005-1120.2023.S1.012
Abstract:
Icing on significant equipment， such as airplane wings， wind turbines， and solar panels， causes aerodynamic changes and important component deformation， which seriously threatens operation safety. However， fabricating flexible， conformal， and robust photothermal de-icing surfaces remains challenging. Herein， a porous and hydrophobic laser induced graphene （LIG） based photothermal anti-frosting/de-icing surface is designed and fabricated by direct laser writing technologies. The LIG film is prepared by laser irradiation on polyimide （PI） film. After laser irradiation， the LIG film exhibits porous structures and a high C/O ratio. Due to the existence of porous structures and a high C/O ratio， the LIG film shows hydrophobic properties （CA， ~123.2°）， high absorption， and good photothermal conversion. Thus， the LIG film displays photothermal anti-frosting and de-icing abilities. The work shows great potential in developing flexible， conformal， and robust photothermal anti-frosting/de-icing surfaces.
Icing on significant equipment， such as airplane wings， wind turbines， and solar panels， causes aerodynamic changes and important component deformation， which seriously threatens operation safety. However， fabricating flexible， conformal， and robust photothermal de-icing surfaces remains challenging. Herein， a porous and hydrophobic laser induced graphene （LIG） based photothermal anti-frosting/de-icing surface is designed and fabricated by direct laser writing technologies. The LIG film is prepared by laser irradiation on polyimide （PI） film. After laser irradiation， the LIG film exhibits porous structures and a high C/O ratio. Due to the existence of porous structures and a high C/O ratio， the LIG film shows hydrophobic properties （CA， ~123.2°）， high absorption， and good photothermal conversion. Thus， the LIG film displays photothermal anti-frosting and de-icing abilities. The work shows great potential in developing flexible， conformal， and robust photothermal anti-frosting/de-icing surfaces.
2023(S1):138-150.
DOI: 10.16356/j.1005-1120.2023.S1.013
Abstract:
The paper studies the damage of epoxy resin-based carbon fiber reinforced ploymer （EP-CFRP） under the coupling effects of high and low temperature， humidity， tensile load. Two high and low temperature cycle intervals （［-40─40 ℃］/［-40─25 ℃］）， two humidity conditions （soaking in water/anhydrous）， and three load levels （unstressed state/30% and 60% of the ultimate load） and their coupling effects are considered. The results indicate that all these three factors have a significant impact on the durability of EP-CFRP. The coupling effects of these factors have strong influence on the tensile strength， while affect little on the tensile modulus. The micro-cracks， which generated at the interface of the resin matrix and the fiber， have been proved to be the main reason for the strength reduction at later stage. The coupling effect of humidity and tensile load promote the expansion of cracks and exacerbates the damage to EP-CFRP. Based on the cumulative damage theory， the residual strength damage model of EP-CFRP under the three-factor coupling action of “high and low temperature cycle-humidity-load” is calibrated by nonlinear fitting method.
The paper studies the damage of epoxy resin-based carbon fiber reinforced ploymer （EP-CFRP） under the coupling effects of high and low temperature， humidity， tensile load. Two high and low temperature cycle intervals （［-40─40 ℃］/［-40─25 ℃］）， two humidity conditions （soaking in water/anhydrous）， and three load levels （unstressed state/30% and 60% of the ultimate load） and their coupling effects are considered. The results indicate that all these three factors have a significant impact on the durability of EP-CFRP. The coupling effects of these factors have strong influence on the tensile strength， while affect little on the tensile modulus. The micro-cracks， which generated at the interface of the resin matrix and the fiber， have been proved to be the main reason for the strength reduction at later stage. The coupling effect of humidity and tensile load promote the expansion of cracks and exacerbates the damage to EP-CFRP. Based on the cumulative damage theory， the residual strength damage model of EP-CFRP under the three-factor coupling action of “high and low temperature cycle-humidity-load” is calibrated by nonlinear fitting method.
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