Mode I Interlaminar Fracture Toughness of Composites Using Slender Double Cantilevered Beam Specimens

Abstract

The use of slender double cantilever beam specimens for measuring the mode I interlaminar fracture toughness was critically evaluated. Experiments were performed with unidirectional composites to judge the validity of using data from multiple crack jumps on a single specimen. Three approaches for calculating the strain energy release rate were compared. These included an energy rate determination of the J I -integral, a compliance calibration procedure and an analytical equation based on linear beam bending. The fracture toughness was overestimated by the latter two approaches. Permanent deflection was seen to accumulate in the arms of the double cantilever beam specimens as the cracked surface area increased. This component of deflection must be accounted for in all forms of analysis with DCB specimens.

Improved Mode I fracture resistance of CFRP composites by reinforcing epoxy matrix with recycled short milled carbon fibre

“…Epoxy resin is the most commonly used matrix phase in fibre-reinforced polymer (FRP), which is normally brittle. Room temperature cured epoxy has Mode I fracture energy of about less than 100-200 J/m 2 [6,7]. This limits the full potential of the weight reduction advantage offered by the composite.…”

Temperature and Moisture Effects in a Particulate Interlayered Composite: Mode I Data Reduction and Toughness

“…[25], where it was originally referred to as 'the J I method'. However, it is fundamentally based on differentiation of the Temperature and Moisture Effects in a Particulate Interlayered Composite strain energy, so the terminology 'SE method' is adopted here.…”

Fracture Behavior of Extren at Room Temperature and 77 K

“…The literature contains numerous measurements of mode 1 interlaminar fracture-toughness in composite materials [4,16,[18][19][20][21]. Several different analytical approaches and specimen geometries have been used.…”

“…The double-cantilever beam (DCB) configuration is one of the most common specimen geometries [4,16,18,19]. Experimental determination of Mode 1 interlaminar fracture toughness of composites using slender double-cantilevered beam specimens has been reviewed thoroughly by Keary et al [21].…”