Ja. Medding et Bj. Love, EVALUATION OF COLLISIONAL DAMAGE IN POLYSTYRENE FOAM CONSTRUCTIONS USING A DUAL HAMMER IMPACT TEST, Polymer engineering and science, 36(9), 1996, pp. 1286-1289
Low intensity impacts can reduce the structural integrity of an expand
ed polystyrene safety helmet by the formation of damage in the foam. T
his reduces the ability of the foam to protect the user under impact c
onditions. In these experiments, the introduction of a rubber inter-la
yer that acts as a cushioning layer to protect the polystyrene shell d
uring light and intermediate impacts was evaluated. The evaluation was
conducted with a dual hammer impact tester, which was constructed for
this purpose. Safety helmet cross sections were simulated by two inch
square test specimens. The dual hammer impact testing identified a da
mage threshold energy above which damage was evident. The introduction
of the soft rubber inter-layer between the foam and outer hard shell
of these specimens increased the impact loading required to damage the
foam by 30%, while the amount of energy transmitted actually increase
d. Further work is being done on perforated rubber systems that will l
ook at damage and energy transmission in these alternative constructio
ns.