Experimental assessment of the mechanical behaviour of 3D woven composite T-joints

Abstract

To understand the influence of the fibre architecture of 3D woven composite T-joints on mechanical performance, as well as the benefits that 3D woven T-joints can offer over the equivalent 2D laminates, experimental testing is performed on two types of 3D woven T-joint with only weave variation at the junction, and one type of 2D woven laminate T-joint. A quasistatic tensile pull-off loading is selected in this work as this out-of-plane load case is one of the typical loading conditions for such T-joint structures. The significant advantages of 3D woven composite T-joints in terms of ultimate strength and damage tolerance over the 2D alternative were identified in the testing. More importantly, this work showed that variation in the fibre architecture can considerably enhance properties such as delamination resistance and total energy absorption to failure, as well as increasing slightly the stiffness and initial failure load. This experimental assessment has demonstrated that using 3D woven reinforcements is an effective way to improve the load-bearing capability of composite T-joints over laminates, and also that this improvement could be optimised with regard to fibre architecture.

Multifunctional auxetic and honeycomb composites made of 3D woven carbon fibre preforms

“…Multifunctional 3D woven composites have the ability to absorb energy through progressive failure, whilst maintaining gradual load profile decay beyond the failure onset 1 , 2 . Consequently, they are of great interest for situations where the ability to withstand crash or impact loading is a design requirement.…”

The influence of structural parameters of fabrics on the bending strength of T-shaped composites

“…26 In the case of T-shaped bonded composites, delamination occurs in this point. 27–29 In the laminates formed in T-shaped composites, there are high stress concentrations in the area of rib-base connection, whereas the 3D woven structure shows relatively uniform stress distributions in the whole structure. 30,31 By means of an appropriate way of structure modification through stitching, the strength properties can be improved.…”

Effect of interlaying UV-irradiated PEEK fibres on the mechanical, impact and fracture response of aerospace-grade carbon fibre/epoxy composites

“…Therefore, enhancing the interlaminar properties, especially the impact resistance and fracture toughness, of FRPs has been a research focus over the last two decades. A number of strategies have been proposed for the interlaminar enhancement of FRPs, including adding second-phase modifiers into the epoxy matrix [1][2][3][4], introducing reinforcement features in the through thickness-direction by 3D-textile weaving [5,6], Z-pinning [7,8], and stitching [9], and interlaying different materials between the plies of the carbon fibre fabrics [10][11][12][13]. While different levels of success in terms of interlaminar enhancement have been achieved, there are also some issues associated with different methods.…”