不同修补工艺下的大厚度树脂基复合材料修补片热应力
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摘要
建立了大厚度碳纤维复合材料修补片与母板共固化的有限元数学模型和计算方法,并采用已有实验结果验证了数学模型和计算方法的正确性。计算了修补片与母板共固化过程中的温度、固化度及热应力变化过程,研究了挖补斜度、纤维铺层方向、纤维铺层顺序等修补工艺参数对修补片固化过程中不同阶段温度及热应力场分布的影响。研究结果表明,挖补斜度对于升温和保温阶段修补片内的热应力影响较大,对于降温结束后的修补片热应力影响较弱。增大挖补斜度,可减小大厚度修补片升温和保温过程的热应力,也可避免较大的热应力集中。在整个固化过程中,0°铺层角对应的修补片内的残余热应力最小,90°铺层角对应的修补片内的残余热应力最大,且在修补片顶部中心有较强的应力集中。为了减小残余热应力,纤维的排布方向应平行于修补片与母板接触面,即母板的铺层方向。对称铺层的修补片在整个固化过程中的热应力较小,而顺序间隔铺层和反对称铺层的修补片内热应力较大,大厚度树脂基复合材料修补片应采用对称的铺层设计原则。
The finite element method is used to simulate the varying process of temperature,curing degree and thermal stress in the co-curing process of thick-sectioned resin matrix composite patch with mother board,and the correctness of the numerical methodology is verified by comparison with the experimental results. The effects of scarf slope,fiber orientation and fiber layup order on distributions of temperature and thermal stress field in patch at different stages during curing process are studied. The results show that the slope of scarf has a great influence on the thermal stress in the patch during the heating and isothermal stages,and has little effect on the thermal stress of the patch at the end of cooling. Increasing the scarf slope can reduce the thermal stress of the patch during the heating and isothermal stages,and can also avoid large thermal stress concentration. During the whole curing process,the residual thermal stress in the patches is the smallest with 0° fiber orientation while the value is the largest with 90°fiber orientation,and there is a strong stress concentration at the center of the top of the patches corresponding to the latter one. In order to reduce the residual thermal stress,the orientation of the fibers should be parallel to the contact surface of the patch with the motherboard,i. e. perpendicular to the direction constrained by the motherboard.Symmetric ply patches have less thermal stress throughout the curing process,while thermal stresses are greater in the patches with sequential spacer plies and anti-symmetric plies. Symmetry ply design principles should be used for resin matrix composites patch plies.
The finite element method is used to simulate the varying process of temperature,curing degree and thermal stress in the co-curing process of thick-sectioned resin matrix composite patch with mother board,and the correctness of the numerical methodology is verified by comparison with the experimental results. The effects of scarf slope,fiber orientation and fiber layup order on distributions of temperature and thermal stress field in patch at different stages during curing process are studied. The results show that the slope of scarf has a great influence on the thermal stress in the patch during the heating and isothermal stages,and has little effect on the thermal stress of the patch at the end of cooling. Increasing the scarf slope can reduce the thermal stress of the patch during the heating and isothermal stages,and can also avoid large thermal stress concentration. During the whole curing process,the residual thermal stress in the patches is the smallest with 0° fiber orientation while the value is the largest with 90°fiber orientation,and there is a strong stress concentration at the center of the top of the patches corresponding to the latter one. In order to reduce the residual thermal stress,the orientation of the fibers should be parallel to the contact surface of the patch with the motherboard,i. e. perpendicular to the direction constrained by the motherboard.Symmetric ply patches have less thermal stress throughout the curing process,while thermal stresses are greater in the patches with sequential spacer plies and anti-symmetric plies. Symmetry ply design principles should be used for resin matrix composites patch plies.
引文
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[13]刘国春,杨文峰,秦文峰,等.平纹编织复合材料层板维修的挖补角度优化分析与试验验证[J].科学技术与工程,2015,18(15):147-150.
[14]Adin H.The investigation of the effect of angle on the failure load and strength of scarf lap joints[J].International Journal of Mechanical Sciences,2012,61(1):24-31.
[15]Harman A B,Wang C H.Improved design methods for scarf repairs to highly strained composite aircraft structure[J].Composite Structures,2006,75(1-4):132-144.
[16]Pinto A M G.,Campilho R D S G,de Moura M F S F,et al.Numerical evaluation of three-dimensional scarf repairs in carbonepoxy structures[J].International Journal of Adhesion and Adhesives,2010,30(5):329-337.
[17]李君,姚学锋,刘应华.复合材料固化过程中温度及应变场分布的解析解[J].清华大学学报(自然科学版),2009,49(5):126-130.
[18]闫勇,庄茁,周正刚,等.树脂比热容对复合材料固化过程数值模拟的影响[J].航空材料学报,2006,26(2):37-40.
[19]White S R,Hahn H T.Process modeling of composite materials:residual stress development during cure,partⅠ.model formulation[J].Journal of Composite Materials,1992,26(16):175-182.
[2]Chun H W,Andrew J G.On the design methodology of scarf repairs to composite laminates[J].Composites Science and Technology,2008,68(1):35-46.
[3]Toudeshky H H,Sadighi M,Vojdani A.Effects of curing thermal residual stresses on fatigue crack propagation of aluminum plates repaired by FML patches[J].Composite Structures,2013,100(6):154-162.
[4]Loos A C,Springer G S.Curing of epoxy matrix composites[J].J.Composite Materials,1983,17(3):135-169.
[5]Zhang K F,Yang Z J,Li Y.A method for predicting the curing residual stress for CFRP/Al adhesive single-lap joints[J].International Journal of Adhesion and Adhesives,2013,46:7-13.
[6]Zhang K M,Gu Y Z,Li M,et al.Effect of rapid curing process on the properties of carbon fiber/epoxy composite fabricated using vacuum assisted resin infusion molding[J].Materials&Design,2014,54:624-631.
[7]Akm S R,Donald W R.Cure cycle optimization of an inorganic polymer matrix material for high temperature fiber reinforced composites[J].Composites Part A:Applied Science and Manufacturing,2016,85:84-93.
[8]陈淑仙,田鹤,秦文峰,等.树脂基复合材料固化过程中的温度和热应力场三维瞬态分析[J].电子科技大学学报,2014,43(4):547-551.
[9]牛勇,穆志韬,李旭东,等.含裂纹金属板复合材料胶接修补结构残余热应力分析[J].玻璃钢/复合材料,2016(5):23-29.
[10]徐建新,张志德,李顶河.复合材料层合板阶梯式挖补修理参数分析[J].机械科学与技术,2011,30(8):1304-1307.
[11]庞杰,刘国春.复合材料挖补修理固化过程残余应力的三维数值模拟[J].玻璃钢/复合材料,2016(8):22-26.
[12]张博明,戴福洪,杜善义.固化工艺规范对复合材料固化残余应力影响的实验研究[J].玻璃钢/复合材料,2010(2):52-61.
[13]刘国春,杨文峰,秦文峰,等.平纹编织复合材料层板维修的挖补角度优化分析与试验验证[J].科学技术与工程,2015,18(15):147-150.
[14]Adin H.The investigation of the effect of angle on the failure load and strength of scarf lap joints[J].International Journal of Mechanical Sciences,2012,61(1):24-31.
[15]Harman A B,Wang C H.Improved design methods for scarf repairs to highly strained composite aircraft structure[J].Composite Structures,2006,75(1-4):132-144.
[16]Pinto A M G.,Campilho R D S G,de Moura M F S F,et al.Numerical evaluation of three-dimensional scarf repairs in carbonepoxy structures[J].International Journal of Adhesion and Adhesives,2010,30(5):329-337.
[17]李君,姚学锋,刘应华.复合材料固化过程中温度及应变场分布的解析解[J].清华大学学报(自然科学版),2009,49(5):126-130.
[18]闫勇,庄茁,周正刚,等.树脂比热容对复合材料固化过程数值模拟的影响[J].航空材料学报,2006,26(2):37-40.
[19]White S R,Hahn H T.Process modeling of composite materials:residual stress development during cure,partⅠ.model formulation[J].Journal of Composite Materials,1992,26(16):175-182.