A novel method for enhancing energy absorption capability by thin-walled sections during the flattening process

This article introduces a novel method to enhance energy absorption capability of thin-walled sections subjected to the quasi-static lateral loading by performing the saw cutting process on simple closed sections with rectangular columns and shaping them into open sections. For this purpose, some simple closed-sectional columns with square and rectangular cross-sections of aluminum were prepared and used to produce different types of open sections with different geometries and lip lengths through the saw cutting process on a face of the columns. Different paths were selected and performed for the saw cutting to obtain six types of square open section and five types of rectangular open sections with different forms of lips. Lateral compression tests between two rigid platens were employed to obtain variations of lateral load and absorbed energy versus lateral displacement and to calculate specific absorbed energy by thin-walled open sections during the flattening process. For each type of rectangular open sections, two similar specimens were prepared and one of them was compressed along the shorter edge and the other one was tested along the longer edge of the cross-section. Also, as benchmarks, some simple specimens with closed section were compressed in the lateral direction to compare their results with energy absorption capacity by the corresponding open sections. Experimental results show that in all types of square and rectangular open-sections, lip length has significant effects on energy absorption capability by the structure; and there is an optimum value for lip length of open section and the column with optimized length of the lips has the maximum absorbed energy. Furthermore, experiments reveal that rectangular open sections which are laterally compressed along their shorter edges absorb higher energy, in compression with the corresponding loaded specimens along the longer edges. Results show that maximum absorbed energy/mass belongs to a square open section of type A with rectangular lips and it is 2.68 times of the corresponding value of the similar closed section, as a valuable result.