Numerical and Experimental Investigation of an Adaptive Socket System for Leg Prosthetic

When amputations of limbs are necessary, prostheses are used to replace the lost functionality. Today, they are mainly made of high-tech materials as carbon fiber reinforced plastics (CFRP), titanium and aluminum. An important part of the prosthesis is the socket, connecting the patients stump with the prosthesis itself. It is in most cases made of CFRP and, by this, a more or less rigid body. This is in contradiction to the fact, that muscles and tissues within the stump are still moving while the patient is walking. To overcome this limitation, an adaptive socket system for femoral amputation is presented in this paper, which allows active deformations by piezoelectric patch actuators integrated to the structure. For design, a finite element model is created. Socket prototypes are built with optimized fabric ply setup and integrated actuators. Finally, the active deflection is tested in a laboratory set up and a passive socket with optimized ply setup is tested with a patient.