Customization and topology optimization of compression casts/braces on two-manifold surfaces

Abstract

This paper applies the topology optimization (TO) technique to the design of custom compression casts/braces on two-manifold mesh surfaces. Conventional braces or casts, usually made of plaster or fiberglass, have the drawbacks of being heavy and unventilated to wear. To reduce the weight and improve the performance of a custom brace, TO methods are adopted to optimize the geometry of the brace in the three-dimensional (3D) space, but they are computationally expensive. Based on our observation that the brace has a much smaller thickness compared to other dimensions and the applied loads are normal forces, this paper presents a novel TO method based on thin plate elements on the two-dimensional manifold (2-manifold) surfaces instead of 3D solid elements. Our working pipeline starts from a 3D scan of a human body represented by a 2-manifold mesh surface, which is the base design domain for the custom brace. Similar to the concept of isoparametric representation, the 3D design domain is mapped onto a two-dimensional (2D) parametric domain. An Finite Element Analysis (FEA) with bending moments is performed on the parameterized 2D design domain, and the Solid Isotropic Material with Penalization (SIMP) method is applied to optimize the pattern in the parametric domain. After the optimized cast/brace is obtained on the 2-manifold mesh surface, a solid model is generated by our design interface and then sent to a 3D printer for fabrication. Compared with the optimization method with solid elements, our method is more efficient and controllable due to the high efficiency of solving FEA in the 2D domain.

Computational Design of Active Kinesthetic Garments

“…It has also been demonstrated on elastic materials [39] as well as structures undergoing large displacements [7]. Closer to our work, topology optimization has moved into the on-body domain where it has been used for personalized cast design [43] and casts designed for thermal comfort [42]. Most recently, Vechev et al demonstrated the design of kinesthetic garments, which are passively reinforced garments designed to resist a single motion [40].…”

Immediate Outcomes and Benefits of 3D Printed Braces for the Treatment of Adolescent Idiopathic Scoliosis

“…Post processing may be required to smooth the surface finish. Zhang and Kwok ( 9 ) used polycarbonate and printed with 4 mm thickness. Polycarbonate is a strong and stiff material, with slower heat conduction.…”

“…The scanned torso file is then modified and sent to a 3D printer for manufacturing a brace. Pilot studies had been conducted in developing 3D printed scoliosis braces (9)(10)(11)(12)(13)15) and exploring treatment effectiveness and in-brace comfort (14). Zhang et al (9) developed a topology optimization technique for 3D printing which can be used to manufacture spinal orthosis.…”

“…Pilot studies had been conducted in developing 3D printed scoliosis braces (9)(10)(11)(12)(13)15) and exploring treatment effectiveness and in-brace comfort (14). Zhang et al (9) developed a topology optimization technique for 3D printing which can be used to manufacture spinal orthosis. Although they reported that their spinal orthosis could reduce 50-70% printing material, validation was only performed on finite element simulation.…”

A Review on: 3D Printed Orthopaedic Cast for Improved Forearm Fracture Rehabilitation

“…The most common TO method is solid isotropic material with penalization parameterization (SIMP) method which rely on Finite Element Analysis (FEA). This method can successfully and efficiently customize an appropriate fit cast, with less material, and improved ventilation but takes time [13]. b) Pressure Distribution of 3D Printed Cast: Traditional cast reports various complications because of unbalanced pressure distribution like cutaneous diseases, compartment syndrome, and vascular comprise.…”