Effect of laser patterning on axial crushing performance of cylindrical 22MnB5 tubes

Abstract This paper describes the effects of various laser patterns on as-received 22MnB5 tubes for selective local strengthening. It has been confirmed that strengthened cross-sectional areas, perpendicular to the axial direction by laser patterning, and uniform strength distributions between the as-received and strengthened area can induce the concertina mode under axial crushing. The auxetic and helical laser patterns demonstrated the highest first peaks in the reaction force and substantial energy absorption due to progressive folding, followed by the concertina mode. Considering the fabrication efficiency, the helical pattern is recommended because it can be easily implemented. To optimise the helical pattern design, the specific pitch size should be based on the line length of a single fold along the neutral surface when the as-received tube collapses. Depending on the geometrical dimensions of the tube, this can increase the number of folds and maximise energy absorption by up to 32.2% during axial crushing.