Crack healing in cross-ply composites observed by dynamic mechanical analysis

Abstract

Cross-ply composites with healable polymer matrices are characterized using dynamic mechanical analysis (DMA). The [90,0] s samples are prepared by embedding layers of unidirectional glass or carbon fibers in 2MEP4FS, a polymer with thermally reversible covalent cross-links previously shown to be capable of healing internal cracks and fully recovering fracture toughness under ideal conditions. After fabrication, cracks in the composites' transverse plies are observed and attributed to residual thermal stresses introduced during processing.Single cantilever bending DMA measurements show the samples exhibit periods of increasing storage moduli with increasing temperature. These results are accurately modeling using simple one-dimensional composite and beam analyses. The effect of cracks on the measured stiffness is considered using a shear lag model, and the predicted crack density of the glass fiber composite falls within a range estimated by microscopy observations. Crack healing is assumed to occur as a function of temperature, and rationales for the onset and conclusion of healing are given.

Static and fatigue tensile properties of cross-ply laminates containing vascules for self-healing applications

“…The latter is responsible for delamination migration in multi-angle laminates [39] and also acts as a delamination initiator or promotes fibre failure at ply interfaces [40]. Transverse damage has been extensively studied as a damage mechanism in cross-ply laminates [30,31,40,41] and this laminate configuration seems suitable for investigating how this damage type can be addressed with a self-healing approach [37,38]. Within cross-ply laminates the first damage mechanism is transverse matrix failure [41], followed by delamination initiation and propagation at the 0/90 interface.…”

Effect of the conversion degree and multiple healing on the healing efficiency of a thermally reversible self‐healing polymer

“…A comprehensive study on self‐healing polymers based on DA reaction was carried out by Nemat‐Nasser et al They employed the same materials used by Chen et al Plaisted et al used DCDC samples to study the healing behavior of the 2MEP4F polymer. They claimed that the fracture resistance of the polymer restored completely after the healing procedure.…”

Comparison of Complex Modulus Provided by Three Different Dynamic Mechanical Analyzers

“…The traditional applications are concerned with the identification of thermal transitions [6][7][8] and how some parameters affect the material's properties [9][10][11][12][13]. Recently, the use of DMA as a characterization technique has been expanded to other studies such as crack healing [14], spatial distribution of material's properties [15] and mechanical properties of heterogeneous materials [16].…”