Structural design for energy absorption during heel strike using the auxetic structure in the heel part of the prosthetic foot

In designing prosthetic foot, the function that can absorb the shock during the heel strike should be considered for the user’s convenience and safety. For this, we designed a 3D printable prosthetic foot that absorbs energy by applying an auxetic structure to the heel part. Through the Finite Element Analysis, the heel strike conditions were established, and energy absorption and maximum stress loaded on the structure were analyzed with respect to the direction and dimensions of the auxetic structure. In addition, the stress concentration that may occur on the upper plate of the heel part according to the round shape design was analyzed. As a result, the designed structure had energy absorption of 3.16 J and the maximum stress of 37.92 MPa, showing that the designed prosthetic foot is practically applicable in the rehabilitation field.