Effect of microchannels on the crashworthiness of fiber-reinforced composites

The integration of microchannels within structural composites enables a range of multifunctional responses such as thermal management and self-healing. In this work, we investigate how microchannels affect the crashworthiness of the host material. Corrugated panels are fabricated with aligned microchannels (ca. 400 µm diameter) at different channel spacing (10 mm and 1.2 mm), orientation with respect to the loading direction, and alignment with respect to the surrounding fiber-reinforcement. Specific energy absorbed (SEA) is measured by compression testing of samples with a chamfer edge trigger. SEA was preserved within 10% for all test cases. Flat (non-corrugated) panels are also tested to demonstrate that microchannels can serendipitously trigger stable, energy absorbing failure modes that lead to improved crashworthiness. Non-vascular panels without an edge chamfer fail catastrophically when compressed. In dramatic contrast, vascular panels fail in a stable fashion triggered by crack initiation at the microchannels, yielding ca. 10 times more energy absorption.