Influence of process induced defects on the failure of composite T-joint specimens

An experimental investigation of the failure load of T-joint structures has been undertaken, with a focus on the influence of process induced defects within the deltoid area. Static pull-off tension tests have been conducted for a comparative assessment. An extensive literature review on the subject to place is also presented. The role of the deltoid area in stabilizing the primary load bearing plies and minimising the volume fraction reduction in the off-axis plies is critical to maximise the failure load and minimise the performance variability of the T-joint structures. A deltoid area reduction of 25%, with no change in the external geometry, yielded a similar mechanical performance to the nominal baseline specimen but with increased variability. However, a reduction of 50% in the deltoid area yielded a strength reduction of 33%. The findings of this study suggest that the reduction in the deltoid area can be tolerated within certain limits.