Experimental and finite element analysis on the performance of vacuum-assisted resin infused single scarf repairs

The high quality composite components produced by the modern manufacturing techniques necessitate the evolvement of repair procedures that produce comparable, in terms of structural integrity, post-repaired components. The vacuum-assisted resin infusion processing method is essentially a modern composite fabrication process and it is currently adapted in the production line of many industries. The technique is considered in the current paper as a repair route where a scarf recess is used as a mould cavity. The effectiveness of the repair technique is evaluated by examining two configurations that are constructed under certain scarf patch design guidelines. The fabrication and quality control procedures of the vacuum-assisted resin infused repair patches are described and experimental tests are carried out to measure their performance. Finite element analysis of the repair configurations is performed, in order to analyze and compare the repair geometries selected. The critical stressed areas from the analyses are identified as potential fracture locations and the stress distributions are used to predict the strength of the repairs using the Tsai-Wu and average stress failure criterion (ASFC). The FE (finite element) results are found to be in good agreement with the experimental findings. The repairs present high strengths approaching that of the control specimens with neither of the configurations perpetuating failure cohesively within the bondline for the taper ratios examined, validating in that way the vacuum-assisted resin infusion repair methodology.