Progressive crushing as a new mechanism of energy absorption. The crushing study of magnesium alloy crash-boxes

• Published in: International journal of impact engineering Vol. 124; pp. 1 - 8
• Main Authors: Kaczyński, Paweł, Gronostajski, Zbigniew, Polak, Sławomir
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2019; Elsevier BV
• Subjects: Ambient temperature; AZ31B; Cracks; Crash-box; Crashworthiness; Crushing; Energy; Energy absorption; Gas absorption; Magnesium alloys; Magnesium base alloys; Temperature; Thin wall structures; Crash-box; Magnesium alloys; AZ31B; Crashworthiness
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2018.10.001

•During the crushing of empty crash boxes, there was no influence of the strain rate on the level of energy absorbed. Strain rate influence was noticed during the crushing of the aluminum foam, which was characterized by 53% greater crashworthiness during the static tests. For this reason, aluminum filled specimens absorbed more energy during the quasi-static tests.•Interaction effect between the crash box (magnesium alloy), and its filling (aluminum foam) have been observed. The energy absorbed by filled crash boxes was 50–70% higher than the sum of energies absorbed by aluminum foam and crash box separately. This occurred both during the static and dynamic tests.•The use of geometric imperfections reduces the level of energy absorbed. Their use, however, has some positive implications. The use of imperfections "corsym: 15,20″ activates the new energy absorbing mechanism which is progressive crushing of specimens occurring at the tup side in a controlled manner.
The article presents the outcome of research concerning the energy absorption of thin-walled structures made of AZ31B magnesium alloy. Tested material cracks brittle during bending at ambient temperature. This well-known problem makes plastic forming of magnesium alloys very difficult. It also causes less frequent use of this material in the production of energy-absorbing elements. Following study demonstrates that the use of proper geometric shape allows to control the process of dynamic crushing and activates a new mechanism of energy absorption that is progressive crushing.