The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical ...The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.展开更多
Carbon fiber reinforced thermoplastic composites(CFRTP)and metals hybrid structures have been widely used in aircraft lightweight manufacturing.However,due to the significant difference in physical and chemical proper...Carbon fiber reinforced thermoplastic composites(CFRTP)and metals hybrid structures have been widely used in aircraft lightweight manufacturing.However,due to the significant difference in physical and chemical properties between CFRTP and metals,there are lots of challenges to connect them with high quality.Laser welding has a good application prospect in CFRTP and metals connection,and a significant research progress has been made in the exploration of CFRTP-metal laser joining mechanism,joining process optimization,joining strength improvement and joining defects controlling.However,there are still some problems need to be solved for this technology application.In this paper,the research progress of CFRTP-metal laser joining was summarized in three major aspects:theoretical modeling and simulation analysis,process exploration and parameter optimization,joint performance improvement and process innovation.And,problems and challenges of this technology were discussed,and the outlook of this research was provided.展开更多
Oxygen-flee copper （Cu） was successfully joined to carbon-fiber-reinforced thermoplastic （CFRTP, polyamide 6 with 20wt% carbon fiber addition） by friction lap joining （FLJ） at joining speeds of 200-1600 mm/min w...Oxygen-flee copper （Cu） was successfully joined to carbon-fiber-reinforced thermoplastic （CFRTP, polyamide 6 with 20wt% carbon fiber addition） by friction lap joining （FLJ） at joining speeds of 200-1600 mm/min with a constant rotation rate of 1500 rpm and a nominal plunge depth of 0.9 ram. It is the first time to report the joining of CFRTP to Cu by FLJ. As the joining speed increased, the tensile shear force （TSF） of joints increased first, and decreased thereafter. The maximum TSF could reach 2.3 kN （ 15 mm in width）. Hydrogen bonding formed between the amide group of CFRTP and the thin Cu20 layer on the Cu surface, which mainly contributed to the joint bonding. The influence factors of the TSF of the joints at different joining speeds were discussed. The TSF was mainly affected by the joining area, the degradation of the plastic matrix and the number and the size of bubbles. As the joining speed increased, the influence factors varied as follows： the joining area increased first and then decreased; the degra- dation of the plastic matrix and the number and the size of bubbles decreased. The maximum TSF was the comprehensive result of the relatively large joining area, small degradation of the plastic matrix and small number and sizes of bubbles.展开更多
为了研究TC4钛合金与碳纤维增强热塑性复合材料(CFRTP)叠层结构摩擦搭接焊(friction lap joining,FLJ)过程中的温度变化及其影响,建立了摩擦热源以及热传导的三维几何模型。利用ABAQUS软件进行模拟,得到了FLJ过程的温度场及热循环曲线,...为了研究TC4钛合金与碳纤维增强热塑性复合材料(CFRTP)叠层结构摩擦搭接焊(friction lap joining,FLJ)过程中的温度变化及其影响,建立了摩擦热源以及热传导的三维几何模型。利用ABAQUS软件进行模拟,得到了FLJ过程的温度场及热循环曲线,分析了旋转速率和焊接速率等参量对温度场的影响规律。并进行了TC4/CFRTP摩擦搭接焊试验,通过连接区域的显微形貌观察分析了温度变化对焊接缺陷的影响。结果表明,模型能够快速、准确模拟TC4/CFRTP叠层结构FLJ过程的温度变化;旋转速率越大、焊接速率越小,则连接区域温度越高;过高的温度导致CFRTP的热塑性基体发生热降解,未能及时排出的热解气体在连接区域形成气泡,气泡数量及大小随温度升高而增多、增大。展开更多
基金financially supported by National Natural Science Foundation of China(Grant Nos.52088102,51879249)Fundamental Research Funds for the Central Universities(Grant No.202261055)。
文摘The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.
基金co-supported by the Shenzhen Basic Research projects(JCYJ20200109144604020,JCYJ20200109144608205 and JCYJ20210324120001003)Yangzhou Hanjiang Science and Technology project(HJZ2021003)+1 种基金Ningbo 2025 major projects(2022Z013)Zhejiang basic public welfare research program(LGG20E050009)。
文摘Carbon fiber reinforced thermoplastic composites(CFRTP)and metals hybrid structures have been widely used in aircraft lightweight manufacturing.However,due to the significant difference in physical and chemical properties between CFRTP and metals,there are lots of challenges to connect them with high quality.Laser welding has a good application prospect in CFRTP and metals connection,and a significant research progress has been made in the exploration of CFRTP-metal laser joining mechanism,joining process optimization,joining strength improvement and joining defects controlling.However,there are still some problems need to be solved for this technology application.In this paper,the research progress of CFRTP-metal laser joining was summarized in three major aspects:theoretical modeling and simulation analysis,process exploration and parameter optimization,joint performance improvement and process innovation.And,problems and challenges of this technology were discussed,and the outlook of this research was provided.
文摘Oxygen-flee copper （Cu） was successfully joined to carbon-fiber-reinforced thermoplastic （CFRTP, polyamide 6 with 20wt% carbon fiber addition） by friction lap joining （FLJ） at joining speeds of 200-1600 mm/min with a constant rotation rate of 1500 rpm and a nominal plunge depth of 0.9 ram. It is the first time to report the joining of CFRTP to Cu by FLJ. As the joining speed increased, the tensile shear force （TSF） of joints increased first, and decreased thereafter. The maximum TSF could reach 2.3 kN （ 15 mm in width）. Hydrogen bonding formed between the amide group of CFRTP and the thin Cu20 layer on the Cu surface, which mainly contributed to the joint bonding. The influence factors of the TSF of the joints at different joining speeds were discussed. The TSF was mainly affected by the joining area, the degradation of the plastic matrix and the number and the size of bubbles. As the joining speed increased, the influence factors varied as follows： the joining area increased first and then decreased; the degra- dation of the plastic matrix and the number and the size of bubbles decreased. The maximum TSF was the comprehensive result of the relatively large joining area, small degradation of the plastic matrix and small number and sizes of bubbles.
文摘为了研究TC4钛合金与碳纤维增强热塑性复合材料(CFRTP)叠层结构摩擦搭接焊(friction lap joining,FLJ)过程中的温度变化及其影响,建立了摩擦热源以及热传导的三维几何模型。利用ABAQUS软件进行模拟,得到了FLJ过程的温度场及热循环曲线,分析了旋转速率和焊接速率等参量对温度场的影响规律。并进行了TC4/CFRTP摩擦搭接焊试验,通过连接区域的显微形貌观察分析了温度变化对焊接缺陷的影响。结果表明,模型能够快速、准确模拟TC4/CFRTP叠层结构FLJ过程的温度变化;旋转速率越大、焊接速率越小,则连接区域温度越高;过高的温度导致CFRTP的热塑性基体发生热降解,未能及时排出的热解气体在连接区域形成气泡,气泡数量及大小随温度升高而增多、增大。
