Topology optimization of the hip bone for gait cycle

This work presents a topology optimization–based approach towards the optimal design of the human hip bone under mechanical loads during walking. The human hip bone is a complex structure that connects the leg with the torso. It transfers body loads from the upper body to the leg during standing, walking, running, and other daily activities during which it bears nearly two to six times the body weight. This indicates that the evolution of the human hip bone might have been guided by mechanical loads during upright gait which is particular in humans. This motivates us to synthesize an optimal hip structure under loads and constraints of the gait cycle using tools of structural topology optimization. The problem is posed as a compliance minimization problem subject to volume constraint under similar boundary conditions and mechanical loads as the natural hip bone. During a few phases of the gait cycle, the optimal designs from topology optimization achieve good similarity with the natural hip bone. The similarity highly increases under a judicious combination of loading of different phases of the gait cycle. No such prior work exists on the optimal design of the human hip bone as a single entity using topology optimization. The new design may find applications in replacement of hip bone and its parts due to failure under high stresses in different types of injuries.