Structural FEA-Based Design and Functionality Verification Methodology of Energy-Storing-and-Releasing Prosthetic Feet

The prosthetic feet that are most often prescribed to individuals with K3/K4 levels of ambulation are the ESR feet. ESR stands for energy-storing and -releasing. The elastic energy is stored by the elastic elements in composite materials (carbon fiber or glass fiber). ESR feet must be developed and optimized in terms of stiffness, taking into account the loads that a healthy human foot undergoes and its kinematics while walking. So far, state-of-the-art analyses show that the literature approaches for prosthetic foot design are not based on a systematic methodology. With the aim of optimizing the stiffness of ESR feet following a methodological procedure, a methodology based on finite element structural analysis, standard static testing (ISO 10328) and functional verification was optimized and it is presented in this paper. During the path of optimization of the foot prototypes, this methodology was validated experimentally. It includes the following: (i) geometry optimization through two-dimensional finite element analysis; (ii) material properties optimization through three-dimensional finite element analysis; (iii) validation test on physical prototypes; (iv) functionality verification through dynamic finite element analysis. The design and functional verification of MyFlex-γ, a three-blade ESR foot prosthesis, is presented to describe the methodology and demonstrate its usability.

Design and Manufacturing of a New Prosthetic Foot

All prosthetic foot designs, adapted in common use, don't imitate the specific qualities of a typical human foot. The premise of this task is to explore current prosthetics so as to plan and assemble a more human like prosthesis. In attempted such a structure, the new prosthesis will show a more extensive scope of qualities than those showed in current prosthetic feet. In doing as such, the new prosthesis will give a closer portrayal of the capacities inalienable to an ordinary human foot. The qualities associated with ordinary strolling incorporate dorsiflexion foot test. The qualities showed in the produced new foot tried are contrasted with those of" SACH foot". The qualities showed by prostheses which compared well with those of a human foot were researched further. Another prosthetic foot is structured and made from composite random E-glass-polyester. The premise of the new prosthetic plan consolidates current prosthetic structure components, such as, prosthetic materials and segments. The scientific part presents the aftereffects of the static investigation by techniques, such as, mathematical strategies (Finite Element method FEM) and experimental methods. Thus the new foot was designed and dorsiflexion were measured. The new prosthetic foot has a good characteristics when compared with the SACH foot, such as good dorsiflexion (7°-6.4°) respectively.Prosthetic foot

Biomechanical Evaluation of Prosthetic Feet Designed Using the Lower Leg Trajectory Error Framework

The walking pattern and comfort of a person with lower limb amputation are determined by the prosthetic foot’s diverse set of mechanical characteristics. However, most design methodologies are iterative and focus on individual parameters, preventing a holistic design of prosthetic feet for a user’s body size and walking preferences. Here we refined and evaluated the lower leg trajectory error (LLTE) framework, a novel quantitative and predictive design methodology that optimizes the mechanical function of a user’s prosthesis to encourage gait dynamics that match their body size and desired walking pattern. Five people with unilateral below-knee amputation walked over-ground at self-selected speeds using an LLTE-optimized foot made of Nylon 6/6, their daily-use foot, and a standardized commercial energy storage and return (ESR) foot. Using the LLTE feet, target able-bodied kinematics and kinetics were replicated to within 5.2% and 13.9%, respectively, 13.5% closer than with the commercial ESR foot. Additionally, energy return and center of mass propulsion work were 46% and 34% greater compared to the other two prostheses, which could lead to reduced walking effort. Similarly, peak limb loading and flexion moment on the intact leg were reduced by an average of 13.1%, lowering risk of long-term injuries. LLTE-feet were preferred over the commercial ESR foot across all users and preferred over the daily-use feet by two participants. These results suggest that the LLTE framework could be used to design customized, high performance ESR prostheses using low-cost Nylon 6/6 material.