Experimental and numerical investigation of the effect of gaps on fatigue behavior of unidirectional carbon/epoxy automated fiber placement laminates

Automated fiber placement (AFP) process provides high potential to repeatability and flexibility required for manufacturing of complex parts in many industries. Performance of such parts can be influenced by AFP manufacturing induced defects such as gaps and overlaps. In this work, the effect of gaps on fatigue behavior of unidirectional carbon/epoxy laminates was investigated. Tension–tension fatigue tests were conducted on defected samples and compared to reference samples free from defects. Infrared thermography technique was used for monitoring of damage propagation during fatigue loading. Moreover, a fatigue progressive damage model (FPDM) was developed and applied to laminates containing gaps to predict fatigue damage progression and failure. The experimental results revealed that the effect of gaps depends on the maximum applied stress during fatigue. The higher is the applied stress, the higher is the reduction in fatigue life. Good agreement was found between the results of fatigue life prediction from the FPDM and the experimental results for defected specimens.

[1]  Larry Lessard,et al.  Progressive Fatigue Damage Modeling of Composite Materials, Part I: Modeling , 2000 .

[2]  Z. Gürdal,et al.  Variable stiffness composite panels : Effects of stiffness variation on the in-plane and buckling response , 2008 .

[3]  G. N. Labeas,et al.  Strength prediction of bolted joints in graphite/epoxy composite laminates , 2002 .

[4]  Zafer Gürdal,et al.  Progressive failure analysis of tow-placed, variable-stiffness composite panels , 2007 .

[5]  Damiano Pasini,et al.  Optimization of variable stiffness composites with embedded defects induced by Automated Fiber Placement , 2014 .

[6]  G. N. Labeas.  FINITE ELEMENT MODELING OF DAMAGE ACCUMULATION IN BOLTED COMPOSITE JOINTS UNDER INCREMENTAL TENSILE LOADING , 2000 .

[7]  L. Lessard,et al.  THE EFFECT OF GAPS AND OVERLAPS ON THE IN-PLANE STIFFNESS AND BUCKLING LOAD OF VARIABLE STIFFNESS LAMINATES MADE BY AUTOMATED FIBER PLACEMENT , 2012 .

[8]  Konstantinos Tserpes,et al.  Modelling of fatigue damage progression and life of CFRP laminates , 2003 .

[9]  Larry Lessard,et al.  Progressive Fatigue Damage Modeling of Composite Materials, Part II: Material Characterization and Model Verification , 2000 .

[10]  Xiangqian Li,et al.  Modelling the effect of gaps and overlaps in automated fibre placement (AFP)-manufactured laminates , 2015 .

[11]  Z. Hashin.  Failure Criteria for Unidirectional Fiber Composites , 1980 .

[12]  Chiara Colombo,et al.  A review of thermographic techniques for damage investigation in composites , 2013 .

[13]  Christophe Baley,et al.  Microstructure and tensile properties of carbon–epoxy laminates produced by automated fibre placement: Influence of a caul plate on the effects of gap and overlap embedded defects , 2015 .

[14]  Zafer Gurdal,et al.  A Theoretical Model to Study the Influence of Tow-drop Areas on the Stiffness and Strength of Variable-stiffness Laminates , 2009 .

[15]  T. Adam,et al.  Life prediction for fatigue of T800/5245 carbon-fibre composites: I. Constant-amplitude loading , 1994 .

[16]  Ravi B. Deo,et al.  Low-Cost Composite Materials and Structures for Aircraft Applications , 2003 .

[17]  Hui Li,et al.  First-principles study on the structural and electronic properties of clean and atomic oxygen adsorbed ZrC(001) surface , 2015 .

[18]  N. Gascons,et al.  Variable-stiffness composite panels: Defect tolerance under in-plane tensile loading , 2014 .

[19]  Moussa Karama,et al.  Damage evolution and infrared thermography in woven composite laminates under fatigue loading , 2006 .

[20]  Damiano Pasini,et al.  Experimental study of the effect of automated fiber placement induced defects on performance of composite laminates , 2011 .

[21]  A. Sawicki,et al.  THE EFFECT OF INTRAPLY OVERLAPS AND GAPS UPON THE COMPRESSION STRENGTH OF COMPOSITE LAMINATES , 1998 .

[22]  Chiara Colombo,et al.  INFLUENCE OF DELAMINATION ON FATIGUE PROPERTIES OF A FIBREGLASS COMPOSITE , 2014 .

[23]  Larry Lessard,et al.  Multiaxial fatigue behaviour of unidirectional plies based on uniaxial fatigue experiments—II. Experimental evaluation , 1997 .

[24]  Gerald Pinter,et al.  Infrared thermographic techniques for non-destructive damage characterization of carbon fibre reinforced polymers during tensile fatigue testing , 2006 .

[25]  Nicklaus C. Kimball.  Open hole compressive behavior of laminates with converging gap defects , 2011 .

[26]  Luke Everett Turoski,et al.  Effects of manufacturing defects on the strength of toughened carbon/epoxy prepreg composites , 2000 .

[27]  V. Dattoma,et al.  Characterization of fatigue damage in long fiber epoxy composite laminates , 2010 .

[28]  T. Adam,et al.  A Power Law Fatigue Damage Model for Fibre-Reinforced Plastic Laminates , 1986 .

[29]  C. Dharan,et al.  A hysteresis-based damage parameter for notched composite laminates subjected to cyclic loading , 2007 .

[30]  Larry Lessard,et al.  Multiaxial fatigue behaviour of unidirectional plies based on uniaxial fatigue experiments — I. Modelling , 1997 .

[31]  Damiano Pasini,et al.  Defect layer method to capture effect of gaps and overlaps in variable stiffness laminates made by Automated Fiber Placement , 2013 .