Next generation of high-performance impact resistant composites with visibility of damage

Composites are truly the materials of the future, due to their excellent properties such as high strength to weight ratio, and their use is rising exponentially, continuing to replace or augment traditional materials in different sectors such as aerospace, automotive, wind turbine blades, civil engineering infrastructure and sporting goods.

A good example is the construction of large aircraft such as the Airbus A350 and Boeing 787 which are 53% and 50% composite by weight, respectively.

However, while the fibre dominant properties guarantee excellent in-plane load-bearing characteristics, traditional composite materials exhibit weak resistance to out-of-plane loads, making them susceptible to barely visible impact damage (BVID) under impact loads that can happen during manufacturing or in service.

BVID can drastically reduce the strength, without any visible warning. Structures that look fine can fail suddenly at loads much lower than expected.

This weak impact resistance together with the complexity of the failure mechanisms typical of composite systems led in the past decade to complex and expensive maintenance/inspection procedures.

Therefore, a significantly greater safety margin than other materials leads to conservative design in composite structures.

Based on these premises, the need is clear for a comprehensive solution that matches the requirements of lightweight structures with the need for high impact resistance and ease of inspection.

This project is aimed at the design and development of next generation of high-performance impact resistant composites with visibility of damage and improved compression after impact strength.

These exceptional properties are caused with ability to visualise and control failure modes to happen in an optimised way.

Energy would be absorbed by gradual and sacrificial damage, strength would be maintained, and there would be visible evidence of damage.

This would eliminate the need for very low design strains to cater for BVID, providing a step change in composite performance, leading to greater reliability and safety, together with reduced design and maintenance requirements, and longer service life.

This is an exciting opportunity to develop this novel proposed technology with my extensive industrial partners, a potentially transformative prospect for the UK composites research and industry.