US Patent 10260968 Polymeric foam deformation gauge

In one general aspect, an apparatus includes at least two conductive elements disposed in a polymeric foam and at least two voltage detectors. Each voltage detector is coupled to a respective conductive element and configured to detect a charge generated by an impact to the polymeric foam within a sensing radius of the respective conductive element. In another general aspect, an apparatus includes a deformation sensor and a voltage detector. The deformation sensor includes a conductive element disposed in a polymeric foam, a portion of the conductive element extending beyond an outer wall of the polymeric foam. The voltage detector is coupled to the portion of the conductive element and detects a charge generated by the deformation sensor responsive to an impact to the polymeric foam.