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LI – Linear Impactor

DSC_9251_CropThe linear impactor was originally designed to simulate head-to-head collision between two NFL football players as a means of evaluating helmet effectiveness. While helmet tests are traditionally done using drop towers, the extreme closing speeds of player-to-player hits makes a drop test not feasible. The helmet being evaluated is positioned on the test headform, typically a Hybrid III automotive head and neck, instrumented to record linear and angular head acceleration as well as upper neck forces and torques.

DSC_9284_Crop.jpgThe machine is charged with a pre-determined set pressure to achieve a desired speed and the impact ram is propelled into the helmeted headform. The advantage of this system is that the headform is free to deflect and rebound in a natural way to study complete head kinematics.

linear_impactor_bus_glazing_testThis system has been demonstrated to be both repeatable and reliable and is adaptable to other situations where bodily impacts are desired in the 5-13 m/s range. The impacting face may be replaced with other rigid or semi-rigid surfaces to simulate a broad range of impact conditions. The headform may be replaced with other parts of a test mannequin or perhaps a dedicated torso membrane. At Biokinetics we have used this machine to evaluate everything from football helmets to passenger bus window glazing in rollover situations.

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