HST Helmet Stiffness

Helmet being tested for shell stiffnessThe fore-aft and lateral crush resistance of a ballistic helmet shell or facial protector is described in several military helmet specifications. The Helmet Stiffness Tester (HST) assesses the structural rigidity of a helmet or helmet component in any direction. It works by squeezing the helmet between two platens where the compression rate, measured force and number of compression cycles is computer programmed. The HST has a peak compressive force of 4450 N (1000 lbf) and a maximum stroke length of 55 cm (22 in).

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