In this study,to address the low efficiency for conventional ultrasonic-assisted drlling(UAD)of carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks,feasibility experiments of non-separation UAD,in which ...In this study,to address the low efficiency for conventional ultrasonic-assisted drlling(UAD)of carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks,feasibility experiments of non-separation UAD,in which continuous cutting between the tool and the workpiece occurs at a high feed rate,are carried out.The experimental results indicate that,compared to conventional separation UAD,the non-separation UAD effectively reduces the cutting forces by 24.2%and 1.9%for CFRP stage and 22.1%and 2.6%for the Ti stage at the feed rates of 50 and 70μm/r,respectively.Furthermore,the non-separation UAD significantly improves hole quality,including higher hole diameter accuracy,lower hole surface roughness,and less hole damage.In addition,the non-separation UAD can decrease adhesive tool wear.This study demonstrates that,compared to conventional drilling(CD),the non-separation UAD can effectively improve drilling quality and tool life while maintaining high efficiency.展开更多
The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6A...The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategy Ⅰ machines both materials with identical machining parameters, while machining strategy Ⅱ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators： tool life, cutting forces, hole quality （including diameter deviation, roundness, roughness, and hole edge quality）. The results demonstrate that heli- cal milling strategy 11 outperformed strategy I, leading to longer tool life （up to 48 holes）, smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish （Ra≤0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP）, eliminating the need for reaming or de-burring.展开更多
A jig was developed for generating a shear wave. A pyramid with an isosceles triangle with two 45o was made of aluminum to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanis...A jig was developed for generating a shear wave. A pyramid with an isosceles triangle with two 45o was made of aluminum to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanism. Also, the signal splitter was connected to the pulser jack on the pulser/receiver and to the longitudinal transducers. Therefore, an experimental way was performed in order to make shear wave on the bottom of aluminum alloyed pyramid. Also, a jig was manufactured and developed for generating a shear wave based on the computer numerical simulation. It is found that the experimentally shear wave variation of newly-designed jig is consistent with computer numerical simulation results and shear wave ultrasonic application can be very useful to detect the defects in CFRP composites.展开更多
Aircraft laminated composite components often suffer a variety of high velocity impacts with large quantity of energy,which usually affects aircraft behavior and would incur component damages,even disastrous consequen...Aircraft laminated composite components often suffer a variety of high velocity impacts with large quantity of energy,which usually affects aircraft behavior and would incur component damages,even disastrous consequences.Therefore,one investigates the impact resistance of a new type of composite material,Ti/CFRP/Ti sandwich structure,and launches impact tests by using an air gun test system.Then one acquires the critical breakthrough rate of the structure and analyzes the damages.The results show that the main failure mode of the front titanium sheet is shear plugging and brittle fracture of adhesive layer with fiber breakage,while the back titanium sheet is severely ripped.The rear damage is worse than the front one.Compared with traditional CFRP laminates,the critical breakthrough rate of Ti/CFRP/Ti sandwich structure is improved by 69.9% when suffered the impact of a bearing ball with 2mm radius.展开更多
The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmen...The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is representative one of the light-weight materials. Based on the respective collapse behavior of aluminum and CFRP member, the collapse behavior of hybrid thin-walled member was evaluated. The hybrid members were manufactured by wrapping CFRP prepreg sheets outside the aluminum hollow members in the autoclave. Because the CFRP is an anisotropic material whose mechanical properties, such as strength and elasticity, change with its stacking condition, the effects of the stacking condition on the collapse behavior evaluation of the hybrid thin-walled member were tested. The collapse mode and energy absorption capability of the hybrid thin-walled member were analyzed with the change of the fiber orientation angle and interface number.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52375399 and 91960203)the Aeronautical Science Foundation of China(No.2022Z045051001).
文摘In this study,to address the low efficiency for conventional ultrasonic-assisted drlling(UAD)of carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks,feasibility experiments of non-separation UAD,in which continuous cutting between the tool and the workpiece occurs at a high feed rate,are carried out.The experimental results indicate that,compared to conventional separation UAD,the non-separation UAD effectively reduces the cutting forces by 24.2%and 1.9%for CFRP stage and 22.1%and 2.6%for the Ti stage at the feed rates of 50 and 70μm/r,respectively.Furthermore,the non-separation UAD significantly improves hole quality,including higher hole diameter accuracy,lower hole surface roughness,and less hole damage.In addition,the non-separation UAD can decrease adhesive tool wear.This study demonstrates that,compared to conventional drilling(CD),the non-separation UAD can effectively improve drilling quality and tool life while maintaining high efficiency.
基金Supported by Key Laboratory for Advanced Manufacturing Technology and Cutting Tools of the Education Department of Heilongjiang Province,National Natural Science Foundation of China(No.51275345)National NC Science and Technology Major Projects(No.2014ZX04001081)National Engineering and Research Center for Commercial Aircraft Manufacturing(No.SAMC13-JS-15-030)
文摘The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategy Ⅰ machines both materials with identical machining parameters, while machining strategy Ⅱ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators： tool life, cutting forces, hole quality （including diameter deviation, roundness, roughness, and hole edge quality）. The results demonstrate that heli- cal milling strategy 11 outperformed strategy I, leading to longer tool life （up to 48 holes）, smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish （Ra≤0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP）, eliminating the need for reaming or de-burring.
文摘A jig was developed for generating a shear wave. A pyramid with an isosceles triangle with two 45o was made of aluminum to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanism. Also, the signal splitter was connected to the pulser jack on the pulser/receiver and to the longitudinal transducers. Therefore, an experimental way was performed in order to make shear wave on the bottom of aluminum alloyed pyramid. Also, a jig was manufactured and developed for generating a shear wave based on the computer numerical simulation. It is found that the experimentally shear wave variation of newly-designed jig is consistent with computer numerical simulation results and shear wave ultrasonic application can be very useful to detect the defects in CFRP composites.
基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Aircraft laminated composite components often suffer a variety of high velocity impacts with large quantity of energy,which usually affects aircraft behavior and would incur component damages,even disastrous consequences.Therefore,one investigates the impact resistance of a new type of composite material,Ti/CFRP/Ti sandwich structure,and launches impact tests by using an air gun test system.Then one acquires the critical breakthrough rate of the structure and analyzes the damages.The results show that the main failure mode of the front titanium sheet is shear plugging and brittle fracture of adhesive layer with fiber breakage,while the back titanium sheet is severely ripped.The rear damage is worse than the front one.Compared with traditional CFRP laminates,the critical breakthrough rate of Ti/CFRP/Ti sandwich structure is improved by 69.9% when suffered the impact of a bearing ball with 2mm radius.
文摘The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is representative one of the light-weight materials. Based on the respective collapse behavior of aluminum and CFRP member, the collapse behavior of hybrid thin-walled member was evaluated. The hybrid members were manufactured by wrapping CFRP prepreg sheets outside the aluminum hollow members in the autoclave. Because the CFRP is an anisotropic material whose mechanical properties, such as strength and elasticity, change with its stacking condition, the effects of the stacking condition on the collapse behavior evaluation of the hybrid thin-walled member were tested. The collapse mode and energy absorption capability of the hybrid thin-walled member were analyzed with the change of the fiber orientation angle and interface number.
