复合材料螺栓连接数值分析及次弯曲效应研究
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摘要
树脂基复合材料因为比强度和比刚度高、可设计性强等优异特性在航空航天领域得到广泛应用。在复合材料结构中连接问题不可避免,螺栓连接由于可靠性高、能够传递较大载荷等优点,成为复合材料结构中常用的连接方式。由于复合材料的脆性及各向异性,螺孔区域的应力较金属材料要复杂的多。复合材料接头破坏是引起结构失效的常见原因,其强度预测和失效分析一直以来是复合材料结构设计人员所关心的问题。本文以ANSYS为技术平台,利用有限元分析软件多方面地研究复合材料连接强度和失效问题,对于降低试验费用并保证连接设计的可靠性,具有一定的工程应用价值。
本文从复合材料损伤机理出发,考虑各种失效模式之间的关联以及材料由拉伸、压缩不同损伤引起的刚度退化率的差异,建立累积损伤分析模型。为了验证该模型的准确性,首先对含孔复合材料层合板进行强度预测和失效分析,研究层合板各种参数对破坏载荷及失效的影响,并与文献试验值进行对比。在此基础上,利用本文建立的累积损伤模型,分析了铺层、拧紧力矩、配合间隙以及搭接方式等因素对单螺栓连接强度和失效的影响。与已有的研究不同,本文在应力分析时建立完整的螺栓连接接头三维有限元模型,并考虑了接头各种接触关系及摩擦行为,提高了应力计算精度。复合材料螺栓连接采用单剪切搭接时,由于偏心载荷引起的附加弯矩使得接头产生侧向位移并使螺栓发生倾斜,发生二次弯曲效应。失效分析表明,二次弯曲使得接头在孔边的接触压力沿厚度方向不均匀,螺栓—螺孔挤压区域发生改变,影响了接头的连接强度和失效模式。因此,在进行单搭接接头设计时必须考虑次弯曲量,本文将建立能够较为准确地模拟接头弯曲特性的有限元模型,研究接头各参数对次弯曲量的影响。本文分析表明,增加搭接区域长度、板厚以及拧紧力矩能够降低接头次弯曲量,而采用间隙配合使得次弯曲效应更加严重,二次弯曲效应一定程度上影响了接头的轴向拉伸刚度。
Polymer matrix composite materials are gradually extensive in the application of the aviation realm because of the high strength-to-weight, high stiffness-to-weight and good designable characteristic. The problem in composites structure connection is unavoidable, bolt connection is commonly used in the composites structure because it can deliver larger load and is more reliable than other connection styles. For stress distribution, it is much more complex than metal material joints on account of the brittleness and anisotropy of composite materials. Damages in composite materials joints often cause structural failure, and strength prediction and failure analysis of composites structure have been the main concerns for designers. In this paper, using the finite element analysis software ANSYS as the technology platform to study strength and failure problems of composites connection in various fields to reduce testing costs and ensure the reliability of connection design, has a certain engineering value.
This paper considers the relationship between the various failure modes of composite materials from the perspective of damage mechanism, as well as different degradation rates of material stiffness under the damage caused by tensile and compression stress in the progressive damage model. At first, in order to verify the accuracy of the model, the paper will predict strength of notched composite laminates and then execute failure analysis, then study impact of various parameters on the failure load and failure mode of laminates, and the calculated value will be compared with the experimental value. On this basis, using the cumulative damage model established, this paper analyses parameters of single bolted joints including overlap, tightening torque, gap and overlap style on connection strength and the impact of failure. In the stress analysis, three-dimensional finite element model of complete bolted joints is established, considering various contact and friction behavior of the bolted joints to improve stress analysis accuracy. The composites joints often have lateral displacement and bolts become tilted due to the additional moment caused by eccentric load while the single shear lap joints are applied in connection, which is called secondary bending effects. Failure analysis showed that the secondary bending makes the contact pressure of the screw hole become uniform along the direction of thickness, bolt-screw extrude areas change, affecting the connection strength and failure mode of the joints. Therefore, while designing single-lap joints, the amount of secondary bending must be considered, this thesis will establish the finite element model that can accurately simulate the bending properties of joints to study the impact of various parameters on the amount of secondary bending. Analysis showed that increasing the length of overlap region, the thickness of plate and the tightening torque can reduce the amount of secondary bending, while clearance make the secondary bending effect more seriously to some extent and affect axial tensile stiffness of the joints.
本文从复合材料损伤机理出发,考虑各种失效模式之间的关联以及材料由拉伸、压缩不同损伤引起的刚度退化率的差异,建立累积损伤分析模型。为了验证该模型的准确性,首先对含孔复合材料层合板进行强度预测和失效分析,研究层合板各种参数对破坏载荷及失效的影响,并与文献试验值进行对比。在此基础上,利用本文建立的累积损伤模型,分析了铺层、拧紧力矩、配合间隙以及搭接方式等因素对单螺栓连接强度和失效的影响。与已有的研究不同,本文在应力分析时建立完整的螺栓连接接头三维有限元模型,并考虑了接头各种接触关系及摩擦行为,提高了应力计算精度。复合材料螺栓连接采用单剪切搭接时,由于偏心载荷引起的附加弯矩使得接头产生侧向位移并使螺栓发生倾斜,发生二次弯曲效应。失效分析表明,二次弯曲使得接头在孔边的接触压力沿厚度方向不均匀,螺栓—螺孔挤压区域发生改变,影响了接头的连接强度和失效模式。因此,在进行单搭接接头设计时必须考虑次弯曲量,本文将建立能够较为准确地模拟接头弯曲特性的有限元模型,研究接头各参数对次弯曲量的影响。本文分析表明,增加搭接区域长度、板厚以及拧紧力矩能够降低接头次弯曲量,而采用间隙配合使得次弯曲效应更加严重,二次弯曲效应一定程度上影响了接头的轴向拉伸刚度。
Polymer matrix composite materials are gradually extensive in the application of the aviation realm because of the high strength-to-weight, high stiffness-to-weight and good designable characteristic. The problem in composites structure connection is unavoidable, bolt connection is commonly used in the composites structure because it can deliver larger load and is more reliable than other connection styles. For stress distribution, it is much more complex than metal material joints on account of the brittleness and anisotropy of composite materials. Damages in composite materials joints often cause structural failure, and strength prediction and failure analysis of composites structure have been the main concerns for designers. In this paper, using the finite element analysis software ANSYS as the technology platform to study strength and failure problems of composites connection in various fields to reduce testing costs and ensure the reliability of connection design, has a certain engineering value.
This paper considers the relationship between the various failure modes of composite materials from the perspective of damage mechanism, as well as different degradation rates of material stiffness under the damage caused by tensile and compression stress in the progressive damage model. At first, in order to verify the accuracy of the model, the paper will predict strength of notched composite laminates and then execute failure analysis, then study impact of various parameters on the failure load and failure mode of laminates, and the calculated value will be compared with the experimental value. On this basis, using the cumulative damage model established, this paper analyses parameters of single bolted joints including overlap, tightening torque, gap and overlap style on connection strength and the impact of failure. In the stress analysis, three-dimensional finite element model of complete bolted joints is established, considering various contact and friction behavior of the bolted joints to improve stress analysis accuracy. The composites joints often have lateral displacement and bolts become tilted due to the additional moment caused by eccentric load while the single shear lap joints are applied in connection, which is called secondary bending effects. Failure analysis showed that the secondary bending makes the contact pressure of the screw hole become uniform along the direction of thickness, bolt-screw extrude areas change, affecting the connection strength and failure mode of the joints. Therefore, while designing single-lap joints, the amount of secondary bending must be considered, this thesis will establish the finite element model that can accurately simulate the bending properties of joints to study the impact of various parameters on the amount of secondary bending. Analysis showed that increasing the length of overlap region, the thickness of plate and the tightening torque can reduce the amount of secondary bending, while clearance make the secondary bending effect more seriously to some extent and affect axial tensile stiffness of the joints.
引文
[1]王耀先.复合材料结构设计.北京：化学工业出版社,2001.1～9
[2]杜善义.先进复合材料与航空航天.复合材料学报,2007.24(1)：1-11
[3](美)牛春匀著.飞机复合材料结构设计与制造,西安飞机工业公司译,西北工业大学出版社,西安,1995
[4]中国航空研究院.复合材料连接手册.北京,航空工业出版社,1994：56～73
[5]Whitney J M, Nuismer R J. Stress fracture criteria for laminated composites containing stress concentration[J]. Journal of Composite Materials,1975.8:253-265
[6]Nuismer R J, Labor J D. Applications of average stress failure criterion. Part I:Tension[J]. Journal of Composite Materials,1978.12:238-245
[7]Yao Weixing. On the notched strength of composite laminates[J]. Composite Science and Technology,1992.45(2):105-110
[8]Reddy Y S, Reddy J N. Linear and non-linear failure analysis of composite laminates with transverse shear [J]. Composite Science and Technology,1992.4 (3):227-255
[9]Petit P H, Waddoups ME. A method of predicting the nonlinear behavior of laminated composites[J]. Journal of Composite Materials,1969.3(1):2-19
[10]Nguyen B N. Three-dimensional modeling of damage in laminated composites containing a central hole. Journal of Composite Materials,1997,31:1672-1693
[11]刘军.复合材料层合板损伤失效分析.东北大学学报,2006.27(1)：76～79
[12]王丹勇.含孔复合材料层合板静拉伸三维逐渐损伤分析.力学学报,2005.37(6)：788-795
[13]鲁国富.含缺口复合材料层合板的三维有限元分析.力学季刊,2008.29(2)：259-265
[14]鲁国富,刘勇,张呈林.含孔复合材料层合板轴向拉伸三维有限元渐进失效分析.南京航空航天大学学报,2009.41(1)：41～47
[15]陈建桥,彭文杰,魏俊红等.考虑内部损伤影响的层合板最终强度预测.固体力学学报,2009.30(1)：1-7
[16]Cooper C, Turvey GJ. Effects of joint geometry and bolt torque on the structural performance of single bolt tension joints in pultruded GRP sheet material. Compos Struct 1995.32(1-4):21-26
[17]Naik RA, Crews JH. Stress analysis method for a clearance-fit bolt under bending loads. AIAAJ 1986.24(8):1348-53
[18]Hyer MW, Klang EC, Cooper DE. The effects of pin elasticity, clearance and friction on the stresses in a pin-loaded orthotropic plate. J Compos Mater 1987.21(3):190-206
[19]McCarthy MA, Lawlor VP, Stanley WF, McCarthy CT. Bolt-hole clearance effects and strength criteria in single bolt, single lap, composite joints. Compos Sci Technol 2002;62(10-11):1415-31
[20]DiNicola AJ, Fantle SL. Bearing strength behaviour of clearance fit fastener holes in toughened graphite/epoxy laminates. In:Camponeshi Jr ET. editor.Composite materials:testing and design, vol.11. ASTM STP 1206.1993. p.220-37
[21]Park HJ. Effect of stacking sequence and clamping force on the bearing strengths of mechanically fastened joints in composite laminates. Compos Struct 2001;53(2):213-21
[22]Camanho PP, Lambert MA. Design methodology for mechanically fastened joints in laminated composite materials. Compos Sci Tech 2006;66(15):3004-20
[23]Nuismer RJ, Labor JD. Application of the average stress failure criterion. Part II: compression. J Compos Mater 1979;13(1):49-60
[24]Chang F-K, Scott RA, Springer G. Strength of mechanically fastened composite joints. J Compos Mater 1982;16(6):470-94
[25]Yamada SE. Analysis of laminate strength and its distribution. J Comp Mat 1978;12:275-84
[26]Chang, F. K. and Chang, K. Y. (1987) A progressive damage model for laminated composites containing stress concen trations. J. Composite Mater.21,834-855
[27]Chang, F. K. and Chang, K. Y. (1987) Post-failure analysis of bolted composite joints in tension or shear-out mode failure. J. Composite Mater.21,809-833
[28]Hashin, Z. (1980) Failure criteria for unidirectional fibre composites. J. Appl. Mech.47, 329-34
[29]Chang, K. Y., Liu, S. and Chang, F. K. (1991) Damage tolerance of laminated composites containing an open hole and subjected to tensile loadings. J. Composite Mater.25,274-301
[30]Chang, F. K. and Lessard, L. B. (1991) Damage tolerance of laminated composites containing an open hole and subjected to compressive loadings:part Ⅰ-analysis. J. Composite Mater.25,2-43
[31]Tan, S. C. (1991) A progressive failure model for composite laminates containing openings. J.Composite Mater.25,556-577
[32]Lessard, L. B. and Shokrieh, M. M. (1995) 2-D modelling of composite pinned-joint failure. J. Composite Mater.29,671-697
[33]Camanho, P. P. and Matthews, F. L. (1999) A progressive damage model for mechanically fastened joints in composite laminates. J. Composite Mater.33,2248-2280
[34]Tserpes KI, Labeas G, Papanikos P, et al. Stength prediction of bolted joints in graphite/ epoxy composite laminates. Composites:Part B,2002,33:521-529
[35]Dano M-L, Kamal E, Gendron G Analysis of bolted joints in composite laminates:strains and bearing stiffness predictions. Compos Struct 2007;79(4):562-70
[36]姜云鹏,岳珠峰.复合材料层合板螺栓连接失效的数值模拟.复合材料学报,2005,22(4)
[37]顾亦磊,赵美英,王芳,万小朋.复合材料层合板机械连接失效分析及铺层优化.陕西理工学院学报,2006.22(4)
[38]徐红炉,王富生,岳珠峰.失效准则和非线性对复合材料层合板螺栓失效强度的影响. 强度与环境,2008.6(35)
[39]王芳,赵美英,万小朋.多钉连接初始破坏强度的工程方法研究.航空计算,2006.36(2)
[40]王丹勇.层合板接头损伤失效与疲劳寿命研究：[博士学位论文].南京：南京航空航天大学能源与动力学院,2006
[41]Schijve J. Some elementary calculations on secondary bending in simple lap joints.Technical report.National Aerospace Laboratory, Amsterdam; 1972
[42]Ireman T,Ranvik T,Eriksson I.On damage development in mechanically fastened composite laminates.Compos Struct 2000.49:151-71
[43]Ireman T.Three-dimensional stress analysis of bolted single-lap composite joints.Compos Struct 1998.43:195-216
[44]Starikov R.Mechanically fastened joints:critical testing of single overlap joints.Technical report.Swedish Defence Research Agency;2002.FOI-R-0441-SE
[45]Van der Linden H.H. Fatigue rated fastener systems-an AGARD coordinated testing programme. Technical Report AGARD No.721,National Aerospace Laboratory, NLR,Amsterdam; 1985
[46]Ekh J, Schon J,Melin G.Secondary bending in multi fastener,composite-to-aluminium single shear lap joints.Composites:Part B,2005.36:195-208
[47]Ekh J, Schon J.Effect of secondary bending on strength prediction of composite,single shear lap joints.Composites Science and Technology,2005.65:953-965
[48]赵强.含孔复合材料层合板的静强度破坏分析研究：[硕士学位论文].南京：南京航空航天大学航空宇航推进理论与工程,2005
[49]Chang FK, Chang KY. A progressive damage model for laminated composites containing stress concentrations. Journal of Composite Materials,1987.21:834-855
[50]王瑁成.有限单元法.北京：清华大学出版社,2002.666-695[51]王武,陶华,刘风雷等.复合材料多排螺栓连接钉载分配的研究.绝缘材料,2006.39(1)
[52]ANSYS.inc, ANSYS非线性基础培训手册／ANSYS高级非线性培训手册／ANSYS非线性培训教程／ANSYS高级接触和螺栓预紧／ANSYS非线性高级求解策略,/www.peraglobal.com.cn/ch/vipservice/buy.html#
[53]Van der Linden H.H. Determination of secondary bending and load transfer. NLR Memorandum SB-81-083U
[54]Jarfall L. Determination of secondary bending and load transfer. Technical report. Saab-Scania;1982
[2]杜善义.先进复合材料与航空航天.复合材料学报,2007.24(1)：1-11
[3](美)牛春匀著.飞机复合材料结构设计与制造,西安飞机工业公司译,西北工业大学出版社,西安,1995
[4]中国航空研究院.复合材料连接手册.北京,航空工业出版社,1994：56～73
[5]Whitney J M, Nuismer R J. Stress fracture criteria for laminated composites containing stress concentration[J]. Journal of Composite Materials,1975.8:253-265
[6]Nuismer R J, Labor J D. Applications of average stress failure criterion. Part I:Tension[J]. Journal of Composite Materials,1978.12:238-245
[7]Yao Weixing. On the notched strength of composite laminates[J]. Composite Science and Technology,1992.45(2):105-110
[8]Reddy Y S, Reddy J N. Linear and non-linear failure analysis of composite laminates with transverse shear [J]. Composite Science and Technology,1992.4 (3):227-255
[9]Petit P H, Waddoups ME. A method of predicting the nonlinear behavior of laminated composites[J]. Journal of Composite Materials,1969.3(1):2-19
[10]Nguyen B N. Three-dimensional modeling of damage in laminated composites containing a central hole. Journal of Composite Materials,1997,31:1672-1693
[11]刘军.复合材料层合板损伤失效分析.东北大学学报,2006.27(1)：76～79
[12]王丹勇.含孔复合材料层合板静拉伸三维逐渐损伤分析.力学学报,2005.37(6)：788-795
[13]鲁国富.含缺口复合材料层合板的三维有限元分析.力学季刊,2008.29(2)：259-265
[14]鲁国富,刘勇,张呈林.含孔复合材料层合板轴向拉伸三维有限元渐进失效分析.南京航空航天大学学报,2009.41(1)：41～47
[15]陈建桥,彭文杰,魏俊红等.考虑内部损伤影响的层合板最终强度预测.固体力学学报,2009.30(1)：1-7
[16]Cooper C, Turvey GJ. Effects of joint geometry and bolt torque on the structural performance of single bolt tension joints in pultruded GRP sheet material. Compos Struct 1995.32(1-4):21-26
[17]Naik RA, Crews JH. Stress analysis method for a clearance-fit bolt under bending loads. AIAAJ 1986.24(8):1348-53
[18]Hyer MW, Klang EC, Cooper DE. The effects of pin elasticity, clearance and friction on the stresses in a pin-loaded orthotropic plate. J Compos Mater 1987.21(3):190-206
[19]McCarthy MA, Lawlor VP, Stanley WF, McCarthy CT. Bolt-hole clearance effects and strength criteria in single bolt, single lap, composite joints. Compos Sci Technol 2002;62(10-11):1415-31
[20]DiNicola AJ, Fantle SL. Bearing strength behaviour of clearance fit fastener holes in toughened graphite/epoxy laminates. In:Camponeshi Jr ET. editor.Composite materials:testing and design, vol.11. ASTM STP 1206.1993. p.220-37
[21]Park HJ. Effect of stacking sequence and clamping force on the bearing strengths of mechanically fastened joints in composite laminates. Compos Struct 2001;53(2):213-21
[22]Camanho PP, Lambert MA. Design methodology for mechanically fastened joints in laminated composite materials. Compos Sci Tech 2006;66(15):3004-20
[23]Nuismer RJ, Labor JD. Application of the average stress failure criterion. Part II: compression. J Compos Mater 1979;13(1):49-60
[24]Chang F-K, Scott RA, Springer G. Strength of mechanically fastened composite joints. J Compos Mater 1982;16(6):470-94
[25]Yamada SE. Analysis of laminate strength and its distribution. J Comp Mat 1978;12:275-84
[26]Chang, F. K. and Chang, K. Y. (1987) A progressive damage model for laminated composites containing stress concen trations. J. Composite Mater.21,834-855
[27]Chang, F. K. and Chang, K. Y. (1987) Post-failure analysis of bolted composite joints in tension or shear-out mode failure. J. Composite Mater.21,809-833
[28]Hashin, Z. (1980) Failure criteria for unidirectional fibre composites. J. Appl. Mech.47, 329-34
[29]Chang, K. Y., Liu, S. and Chang, F. K. (1991) Damage tolerance of laminated composites containing an open hole and subjected to tensile loadings. J. Composite Mater.25,274-301
[30]Chang, F. K. and Lessard, L. B. (1991) Damage tolerance of laminated composites containing an open hole and subjected to compressive loadings:part Ⅰ-analysis. J. Composite Mater.25,2-43
[31]Tan, S. C. (1991) A progressive failure model for composite laminates containing openings. J.Composite Mater.25,556-577
[32]Lessard, L. B. and Shokrieh, M. M. (1995) 2-D modelling of composite pinned-joint failure. J. Composite Mater.29,671-697
[33]Camanho, P. P. and Matthews, F. L. (1999) A progressive damage model for mechanically fastened joints in composite laminates. J. Composite Mater.33,2248-2280
[34]Tserpes KI, Labeas G, Papanikos P, et al. Stength prediction of bolted joints in graphite/ epoxy composite laminates. Composites:Part B,2002,33:521-529
[35]Dano M-L, Kamal E, Gendron G Analysis of bolted joints in composite laminates:strains and bearing stiffness predictions. Compos Struct 2007;79(4):562-70
[36]姜云鹏,岳珠峰.复合材料层合板螺栓连接失效的数值模拟.复合材料学报,2005,22(4)
[37]顾亦磊,赵美英,王芳,万小朋.复合材料层合板机械连接失效分析及铺层优化.陕西理工学院学报,2006.22(4)
[38]徐红炉,王富生,岳珠峰.失效准则和非线性对复合材料层合板螺栓失效强度的影响. 强度与环境,2008.6(35)
[39]王芳,赵美英,万小朋.多钉连接初始破坏强度的工程方法研究.航空计算,2006.36(2)
[40]王丹勇.层合板接头损伤失效与疲劳寿命研究：[博士学位论文].南京：南京航空航天大学能源与动力学院,2006
[41]Schijve J. Some elementary calculations on secondary bending in simple lap joints.Technical report.National Aerospace Laboratory, Amsterdam; 1972
[42]Ireman T,Ranvik T,Eriksson I.On damage development in mechanically fastened composite laminates.Compos Struct 2000.49:151-71
[43]Ireman T.Three-dimensional stress analysis of bolted single-lap composite joints.Compos Struct 1998.43:195-216
[44]Starikov R.Mechanically fastened joints:critical testing of single overlap joints.Technical report.Swedish Defence Research Agency;2002.FOI-R-0441-SE
[45]Van der Linden H.H. Fatigue rated fastener systems-an AGARD coordinated testing programme. Technical Report AGARD No.721,National Aerospace Laboratory, NLR,Amsterdam; 1985
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