Method and apparatus for simulating head impacts for helmet testing

A method of testing a helmet, said method comprising:

• providing an impact delivery unit having a force actuator for delivering an impact force;
• providing at least one head form such that said impact delivery unit can deliver an impact force to said at least one head form;
• impacting said at least one head form with said force actuator so as to rotate said at least one head form about a plurality of different axes of rotation in sequence, wherein movement of said at least one head form during each rotation is constrained to be able to move only in rotation and only about one axis of rotation of said plurality of axes at any time;
• obtaining an indicator of each acceleration of said at least one head form when rotated about each of said plurality of axes;
• from the indicators of acceleration, determining the rotational acceleration of each said head form during rotations about each of said plurality of axes of rotation.

A method for testing a helmet, said method comprising:

• selecting a first head form from a plurality of head forms, each of said plurality of head forms each being configured to rotate only about a different axis of rotation of a plurality of axes of rotation;
• installing a helmet on said first head form;
• exerting a force against said helmet at a designated location to thereby cause said selected head form to rotate about a first axis of rotation;
• measuring an indicator of rotational acceleration about said first axis of rotation of said selected head form;
• determining a rotational acceleration of said selected head form about said corresponding first axis of rotation;
• selecting a second head form from a plurality of head forms;
• installing said helmet on said second head form;
• exerting a force against said helmet at a designated location to thereby cause said selected head form to rotate about said second axis of rotation;
• measuring an indicator of rotational acceleration about said second axis of said selected head form;
• determining a rotational acceleration of said selected head form about said second axis of rotation.

A method for testing a helmet, said method comprising:

• i. selecting a head form adapted and constrained to rotate about a first axis of rotation of a plurality of axes of rotation;
• ii. impacting the head form at a first designated location with a force actuator operable to exert a constant force against said head form to thereby cause said selected head form to rotate about said one axis of rotation;
• iii. measuring an indicator of rotational acceleration in relation to said first axis of said head form;
• iv. determining a baseline rotational acceleration in relation to said first axis of said head form;
• v. installing a helmet on said head form;
• vi. impacting the helmet installed on said head form at said first designated location with a force actuator operable to exert said constant force against said head form to thereby cause said selected head form to rotate about said one axis of rotation;
• vii. measuring an indicator of rotational acceleration in relation to said first axis of said head form;
• viii. determining a rotational acceleration of said selected head form when said helmet is installed on said head form;
• and
• ix. determining a degree of protection against rotational acceleration in relation to said first axis afforded by the helmet for said impact point;
• x. selecting a head form adapted and constrained to rotate about a second axis of rotation of a plurality of axes of rotation;
• xi. impacting the head form at a second designated location with a force actuator operable to exert a constant force against said head form to thereby cause said selected head form to rotate about said second axis of rotation;
• xii. measuring an indicator of rotational acceleration of said head form;
• xiii. determining a baseline rotational acceleration in relation to said second axis of said head form;
• xiv. installing said helmet on said head form;
• xv. impacting the helmet installed on said head form at said second designated location with a force actuator operable to exert said constant force against said head form to thereby cause said selected head form to rotate about said one axis of rotation;
• xvi. measuring an indictor of rotational acceleration in relation to said second axis of said head form;
• xvii. determining a rotational acceleration in relation to said second axis of said selected head form when said helmet is installed on said head form;
• and
• xviii. determining a degree of protection against rotational acceleration in relation to said second axis afforded by the helmet for said impact point.

A method for testing a helmet, said method comprising:

• providing a head form adapted and constrained to rotate separately about a first axis of rotation and a second axis of rotation;
• generating a baseline rotational acceleration in relation to said first axis of said head form;
• generating a rotational acceleration in relation to said first axis when said helmet is installed on said head form;
• determining a degree of protection against rotational acceleration in relation to said first axis afforded by the helmet;
• generating a baseline rotational acceleration in relation to said second axis of said head form;
• generating a rotational acceleration in relation to said second axis when said helmet is installed on said head form;
• and
• determining a degree of protection against rotational acceleration in relation to said second axis afforded by the helmet.

A method for comparing first and second helmets, said method comprising:

• providing a head form adapted and constrained to rotate separately about a first axis of rotation and a second axis of rotation;
• generating a rotational acceleration in relation to said first axis when said first helmet is installed on said head form;
• generating a rotational acceleration in relation to said first axis when said second helmet is installed on said head form;
• comparing the rotational acceleration in relation to said first axis and the second axis between when the first and second helmets are installed on the head form.

A method for comparing first and second helmets, said method comprising:

• i. selecting a first head form adapted and constrained to rotate about a first axis of rotation of a plurality of axes of rotation;
• ii. installing a first helmet on said first head form;
• iii. exerting a first force on said first helmet installed on said first head form at a first designated location to thereby cause said first head form to rotate about said first axis of rotation;
• iv. measuring an indicator of rotational acceleration in relation to said first axis of said first head form;
• v. determining a rotational acceleration in relation to said first axis of said first head form when said first helmet is installed on said first head form;
• and
• vi. installing a second helmet on said first head form;
• vii. exerting said first force on said second helmet installed on said first head form at said first designated location to thereby cause said first head form to rotate about said second axis of rotation;
• viii. measuring an indicator of rotational acceleration in relation to said second axis of said first head form;
• ix. determining a rotational acceleration in relation to said second axis of said first head form when said second helmet is installed on said first head form;
• and
• x. comparing the rotational accelerations in relation to said first axis between said first and second helmets;
• xi. selecting a second head form adapted and constrained to rotate about a second axis of rotation of a plurality of axes of rotation;
• xii. installing said first helmet on said second head form;
• xiii. exerting a second force on said first helmet installed on said second head form at a second designated location to thereby cause said second head form to rotate about said second axis of rotation;
• xiv. measuring an indicator of rotational acceleration in relation to said second axis of said second head form;
• xv. determining a rotational acceleration in relation to said second axis of said second head form when said first helmet is installed on said second head form;
• xvi. installing a second helmet on said second head form;
• xvii. exerting said force on said second helmet installed on said second head form at said second location to thereby cause said second head form to rotate about said second axis of rotation;
• xviii. measuring an indicator of rotational acceleration in relation to said second axis of said second head form;
• xix. determining a rotational acceleration in relation to said second axis of said second head form when said second helmet is installed on said head form;
• xx. comparing the rotational accelerations in relation to said first axis between said first and second helmets.

An apparatus comprising:

• at least one head form;
• a helmet configured for attachment to said at least one head form;
• an impact delivery unit for delivering an impact force to said helmet at at least one designated location when said helmet is attached to said at least one head form;
• said at least one head form being selectively rotatable about a plurality of different axes of rotation, wherein movement of said at least one head form is constrained to be able to move only in rotation and only in rotation about one axis of rotation of said plurality of axes at any time;
• a measuring system for providing an indicator of the acceleration of said at least one head form when rotated about each of said plurality of axes;
• wherein when said impact delivery unit delivers an impact to said at least one head form, said measurement device associated with each said head from measures the acceleration of each said head form during rotations about each of said plurality of axes of rotation.