A novel interpretation of fatigue delamination growth behavior in CFRP multidirectional laminates

Abstract

Two Paris-type models are proposed to characterize the fatigue delamination growth (FDG) behavior in CFRP laminates. The crack-driving forces denoted by two definitions of the strain energy release rate (SERR) range against the fatigue delamination resistance of composite materials are introduced to control the FDG. The first definition is the square of the difference between the square root of maximum SERR and that of minimum SERR. The second one is the arithmetic difference between the maximum and minimum SERR. A series of fatigue delamination tests of CFRP multidirectional laminates under various stress ratios and mode-mixity ratios were carried out. Among different Paris relations, the FDG rate corrected by the first model exhibits a linear relationship with R-ratio dependency, and the second model further removes the R-ratio dependence, under different mode-mixity ratios, on a log-log scale. The experimental results indicate that the presented models can provide more generic descriptions and a proper interpretation of the FDG behavior in CFRP multidirectional laminates.

Experimental study on delamination migration in multidirectional laminates under mode II static and fatigue loading, with comparison to mode I

“…Furthermore, delamination migration is not only difficult to avert, but it may also be seen to take place in various load scenarios [7][8][9], e.g. low-velocity impact [9], debonding between the flange and skin of an integrally stiffened panel [8], delamination growth emanating from embedded defects and notches [10][11][12] and shear loading on non-unidirectional laminates [13][14][15][16][17]. In regard to numerical simulation, numerous studies have focused on the modelling of delamination by using the virtual crack closure technique [18][19][20] and cohesive zone models [21,22].…”

Delamination migration in multidirectional composite laminates under mode I quasi-static and fatigue loading

“…The migration event is more generally difficult to suppress, as it can be initiated by various loading scenarios; e.g. low-velocity impact [13], debonding between the flange and skin of integrally stiffened panels [14], tensile loading applied to composites with embedded defects and notches [15][16][17][18] and shear loading in non-unidirectional laminates [19][20][21][22][23]. These examples highlight that knowledge of single-interface delamination growth is not sufficient for a complete understanding of real applications.…”

Examination of Tensile Strength and End Notch Flexure Properties of Unidirectional Basalt Fabric Reinforced Polymer Composites With and Without Addition of Biochar Filler

“…Thus, the study of ENF specimen will be examined and compared with different specimen and analysed. Thus the energy release rate and strain energy release rate will be studied [13][14][15][16].…”