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Effect of the SMA Trigger on the Energy Absorption Characteristics of CFRP Circular Tubes

Quasi-static compressive tests were performed on carbon fiber reinforced polymer (CFRP) circular tubes to examine their axial crushing behaviors. Stable progressive crushing processes with brittle fracturing crushing mode were observed during the experiments. It is found that the crushing triggers including the ply drop off trigger and the shape memory alloy (SMA) trigger introduced in the specimens can efficiently initiate a stable progressive crushing process and significantly improve the specific energy absorption (SEA) as well as the crushing load efficiency (CLE) of the specimens. It is important to mention that the SMA trigger provides 37.2% increase of the SEA and 28.0% increase of the CLE, respectively, as compared with the specimens without a crushing trigger. Moreover, the SEA and the CLE of the composite tubes with the SMA trigger are 22.8% and 4.3% higher than those of specimens with the ply drop off trigger. In addition, the significant improvement of the SEA and the CLE is achieved with only a little increase of the initial peak-specific crushing stress.