The article presents a finite element simulation for the stress analysis of a transfemoral prosthesis with damping for a 100 kg person in the balancing phase. The maximum force is exerted at this stage when the person supports his or her whole body on a single foot. Materials used included stainless steel and polymer matrix composites, for which mechanical testing was performed. The study applied the SolidWorks simulation software tools, where material properties were specified for each part that composes the prosthesis and considered loads, the fastenings, and the meshing. The simulation resembles the manufacturing process for each component, including the sole built by the novel composite fused deposition modeling technique. As a result of the simulation, the stress, displacement fields, and safety factor are obtained. Analysis of the safety factor indicates that the components can withstand the loads imposed. Finally, a fatigue analysis indicated that the most critically loaded component lasts at least 294,107 cycles at maximum constant loading.

Passive and fixed-damping transfemoral prostheses cannot adapt their resistance to the phase-dependent demands of human gait, and microprocessor-controlled commercial knees remain out of reach for most amputees. We present a fuzzy logic controller that modulates a magnetorheological (MR) damper directly from gait phase and knee joint angle, since linear state-feedback and discrete PI designs are valid only at a single linearization point and require retuning across the gait cycle. The controller is formalized as a fuzzy-basis-function expansion with established coverage and Lipschitz continuity; the universal-approximation property of Mamdani systems grounds fuzzy logic theoretically but does not certify this 8-rule controller’s performance, established empirically instead. A dissipativity-based Lyapunov argument and a numerical sweep establish local closed-loop stability and bounded, rate-limited actuation. The damper couples to the knee through a shaft–bearing–housing assembly sized by free-body and Goodman fatigue analysis and verified by finite-element analysis, with the control pipeline embedded on an ESP32 microcontroller in a 2 kg prototype, corresponding to Technology Readiness Level (TRL) 5–6. In a single-subject case study with one transfemoral amputee, the controller achieved the lowest mean RMSE (0.0557 over three trials) against a non-disabled gait reference among five compared conditions, improving on the best fixed voltage by 20.2% and a passive prosthesis by 6.8×; these are single-subject feasibility results, not a claim of generalizable performance.