Intelligent Digital Structural Design System: from Civil Infrastructure to Orthopaedics Device

Medical devices:
Spinal cage & femoral implant
Lumbar spinal fusion and total hip arthroplasty are common orthopedic surgeries. However, their solid-filling implants does not fit patient physique. Due to mismatch of stiffness, loading concentrates in stiff metal implants, leading to decreased stress in vertebrae and femoral shaft. Since inadequate stress stimulus causes bone degeneration, risk of fusion failure and revision surgery enhances.
The design system automatically reconstructs digital model from a patient-specific CT scan. The optimal porosity distribution is determined by multi-scale topology optimization algorithm to replicate pre-implantation bone stress. The product is 3D printed using biocompatible titanium material. Compared to solid-filling products, cage and implant with optimal lattice design reduces bone resorption by 62% and 89% of volume respectively.

Civil infrastructures:
Stainless & high-strength steel joints
Large span and grid shell structures require complicated spatial joints to connect its members and often involve on-site welding. However, the heat produced during on-site welding induces residual stress and even local imperfections. The proposed topology optimization framework changes the failure mode of steel joint with the aim of obtaining the optimal material distribution under specific volume constraints to improve joint stiffness. The joint after optimization can be easily assembled without on-site welding, which can be further extended to the design of multi-planar joints to enhance construction efficiency and guarantee structural quality.

Benefits to society
Two applications provide remarkable benefits to the community. The optimized joint utilizes fewer materials to achieve better structural performance and cost-effectiveness. It enhances construction efficiency via avoiding on-site welding. The design system of two orthopedic implants generates tailored devices with targeted performance automatically at lower cost. Not only can it facilitate patients’ post-surgery recovery, but also saves medical resources. Further, the automaticity and compatibility of the established digital design framework open a novel chapter of digital manufacturing, enhancing its market competitiveness.