Influence of the stacking sequence and crack velocity on fracture toughness of woven composite laminates in mode I

Abstract

a b s t r a c tWoven composites are well-known for their good transverse properties and for their high fracture toughness. The damage mechanisms leading to delamination in woven composites are identified in mode I. The influence of several parameters, including the draping sequence and the fiber/matrix interface on the fracture toughness of woven composite laminates is studied. Pure mode I tests are carried out on several carbon/epoxy and glass/epoxy woven composites configurations and the differences observed are discussed from a fractographic point of view. A novel experimental method is designed to perform dynamic pure mode I tests. The study illustrates the high fracture toughness of the composites made of woven fabrics as well as the influence of the orientation of the plies, the nature of the fibers and the addition of an adhesive film on the fracture toughness in mode I. The dynamic tests prove that, on the configurations tested and for crack velocities up to 100 m/s, the crack propagation velocity has a limited effect on the value of G Ic .

Mode I interlaminar fracture toughness of carbon‐epoxy coupons with embedded ceramic sensors

“…For [45/45] ply interface, the crack encounters more intersections than for [0/90] interfaces. Crack growth is off the axis of the fibers, demanding more energy to propagate the crack and resulting in a higher fracture toughness . In the case of instrumented coupons, there is also full separation of the sensor and its wire connection from the delamination surface (Figure b).…”

“…The delamination surfaces are flatter than [0/90] 4 , showing smaller resin pockets between the fabric weaves. [30,31] In the case of instrumented coupons, there is also full separation of the sensor and its wire connection from the delamination surface (Figure 9b). Previous works showed that each warp/ weft tows intersection works similar to an obstacle for the crack propagation.…”

Mode I fracture toughness of fiber-reinforced polymer composites: A review

“…DCB is an ideal specimen type in mode I interlaminar fracture tests [4,9,41,45,114,120,123,127,146–154]. It comprises of a rectangular composite specimen with uniform thickness as shown in Figure 6(a).…”

Determination of mode I dynamic fracture toughness of IM7-8552 composites by digital image correlation and machine learning

“…For Jih and Sun [26], an advantage of this method compared to the J-Integral is that it can easily separate the energy release rate for each fracture mode without knowing, a priori, the mixed-mode ratio. Navarro et al [28] followed the work of Guo and Sun [29], which similarly to Sun and Hun [25], used the finite elements method with node releasing strategy to calculate mode I dynamic fracture toughness of carbon/epoxy and glass/epoxy composites. Differently from Jih and Sun [26], they used the energy balance (total strain-energy and total kinetic-energy)…”