Compression behavior of the CFRP square tubes after low‐velocity impact

Abstract This work investigates the impact resistance and compression after impact (CAI) strength of carbon fiber‐reinforced polymer (CFRP) square tubes with varying wall thicknesses and diameters. Low‐velocity impact (LVI) tests are conducted on CFRP square tubes with three wall thicknesses and diameters at four incident energy levels, followed by compression tests on the impacted specimens. The results, including impact response history and failure morphology captured by the digital image correlation (DIC) technology, reveal that augmenting the wall thickness of CFRP square tubes substantially boosts their impact resistance and load‐bearing capabilities, evidenced by a remarkable 176.17% enhancement in CAI strength when the wall thickness is increased from 1.5 to 2.5 mm under a 20 J impact energy. Conversely, enlarging the diameter tends to diminish rigidity and impact resistance; however, it marginally augments CAI strength and residual strength. Highlights CAI strength of CFRP square tubes with varying geometries was investigated. DIC graph providing a comprehensive understanding of failure mechanisms. Failure mode was distinguished based on the low‐velocity characterization.