Effect of residual stress on the bending response of L-shaped composite laminates

2020 ◽  
Vol 246 ◽  
pp. 112425
Author(s):  
Kenan Cinar ◽  
Ibrahim Guven ◽  
Nuri Ersoy
Keyword(s):  
Residual Stress ◽  
Composite Laminates ◽  
Bending Response

Acoustic emission characterization of local bending behavior for adhesively bonded hybrid external patch repaired glass/epoxy composite laminates

2018 ◽  
Vol 18 (3) ◽  
pp. 739-756 ◽  
Author(s):  
J Jefferson Andrew ◽  
V Arumugam ◽  
C Ramesh
Keyword(s):  
Acoustic Emission ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Glass Fibers ◽  
Residual Deformation ◽  
Woven Fabrics ◽  
Adhesively Bonded ◽  
Indentation Tests ◽  
Bending Response

This article investigates the influence of homogeneous and hybrid external patches based on glass and Kevlar plain weave woven fabrics on local bending response of adhesively bonded external patch repairs in damaged glass/epoxy composite laminates. The intent of using hybrid external patches was to combine the excellent high displacement to failure property of Kevlar fiber as a ductile reinforcement with the superior mechanical property of glass fiber as a brittle reinforcement. The undamaged normal specimens were taken as the standard specimen for evaluation of residual mechanical properties. In all hybrid patches, the proportion of Kevlar and glass fibers was equal (i.e. 50% of Kevlar and 50% of glass by volume fraction), while lay-up configurations were different. This further allowed studying the associated effects of hybridization and lay-up configuration on local bending response of the repaired laminates. All the specimens were subjected to cyclic quasi-static indentation tests with a step loading method. The indentation tests have also been monitored in real time by acoustic emission system. The acoustic emission results illustrated various damage profiles and correlates with the mechanical test results to point out the load to a transformation in damage mechanisms during indentation loading with respect to the effect of each patch material on the performance of the repaired glass/epoxy specimens. Results showed that hybridization and lay-up configurations of the external patches played a significant role on local bending response (i.e. ultimate load, stiffness, residual deformation, displacement to failure, and damage pattern) of the repaired glass/epoxy specimens. Specimens repaired using intra-ply hybrid patches showed the best local bending response.

Measurement of residual stress in thick section composite laminates using the deep-hole method

2005 ◽  
Vol 47 (11) ◽  
pp. 1718-1739 ◽  
Author(s):  
M.G. Bateman ◽  
O.H. Miller ◽  
T.J. Palmer ◽  
C.E.P. Breen ◽  
E.J. Kingston ◽  
...  
Keyword(s):  
Residual Stress ◽  
Composite Laminates ◽  
Thick Section ◽  
Deep Hole

Determination of residual stress and thermal history for IM7/977-2 composite laminates

2005 ◽  
Vol 65 (13) ◽  
pp. 2014-2024 ◽  
Author(s):  
William A. Schulz ◽  
Donald G. Myers ◽  
Tom N. Singer ◽  
Peter G. Ifju ◽  
Raphael T. Haftka
Keyword(s):  
Residual Stress ◽  
Thermal History ◽  
Composite Laminates

Monitoring of Multidirectional and Cure-Induced Strain in CFRP Laminates Using FBG Sensors

2019 ◽  
Vol 953 ◽  
pp. 72-79 ◽  
Author(s):  
Cheng Biao Jiang ◽  
Li Hua Zhan ◽  
Xiao Bo Yang ◽  
Xiao Ping Chen ◽  
Zi Jun Lin ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Strain ◽  
Composite Laminates ◽  
Compressive Strain ◽  
Fibre Bragg Grating ◽  
Cfrp Laminates ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Fbg Sensors ◽  
Curing Cycle

During the curing cycle, the residual stress has influence on cure-induced deformation for carbon fiber reinforced plastics (CFRP) laminates, which is highly susceptible to the ply design. Therefore, the change laws of strain and the effect of residual stress in CFRP laminates after curing, which is of great significance to ply design, were cleared by using the combining pattern of thermocouple and fibre Bragg grating (FBG) sensors. For the FBG sensors embedded with different directions in lay-up CFRP laminates, the temperature and strain in different directions of composite laminates were obtained in real-time. Monitoring results show that compared with strain in 45° direction, the carbon fibers (CF) act stronger to inhibit strain in 0° direction and weaker to inhibit strain in 90° direction of resin. After curing, the residual strain in 0° direction is tensile strain, and the residual strain in 45° direction and 90° direction are compressive strain. Meanwhile the value of residual strain in 90° direction is greater than that in 45° direction.

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