Simple incision and suture modeling on fixed structured grids.

This paper presents a simple yet versatile approach to simulate skin incisions and suturing using nonlinear finite element analysis on a fixed structured grid with a spring-based suture model. Incisions and wounds are introduced by element removal and the sutures are discretely modeled by applying linear constraint relations pairwise to groups of nodes. Two numerical examples utilize the closing of an elliptical wound to study the influence of the number of sutures and their location, and two test cases use the Z-plasty transposition flap technique to investigate the versatility of the proposed method and for comparison with state-of-the-art results.

medical device testing of anatomically and mechanically conforming patient-specific spinal fusion cages designed by full-scale topology optimisation.

A full-scale topology optimisation formulation has been developed to automate the design of cages used in instrumented transforaminal lumbar interbody fusion. The method incorporates the mechanical response of the adjacent bone structures in the optimisation process, yielding patient-specific spinal fusion cages that both anatomically and mechanically conform to the patient, effectively mitigating subsidence risk compared to generic, off-the-shelf cages and patient-specific devices. In this study, medical device testing on a cohort of seven patients was performed to investigate the effectiveness of the anatomically and mechanically conforming devices using titanium and PEEK implant materials.

Anatomically and mechanically conforming patient-specific spinal fusion cages designed by full-scale topology optimization.

Cage subsidence after instrumented lumbar spinal fusion surgery remains a significant cause of treatment failure, specifically for posterior or transforaminal lumbar interbody fusion. Recent advancements in computational techniques and additive manufacturing, have enabled the development of patient-specific implants and implant optimization to specific functional targets. This study aimed to introduce a novel full-scale topology optimization formulation that takes the structural response of the adjacent bone structures into account in the optimization process.

Experimental characterization of a shape optimized acoustic lens: Application to compact speakerphone design.

This work presents the shape optimization and subsequent experimental validation of an acoustic lens with application to a compact loudspeaker, such as found in commercial speakerphones. The shape optimization framework is based on a combined lumped parameter and boundary element method model using free form deformation geometry parameterization. To test the optimized design, the loudspeaker lens is three-dimensionally printed and experimentally characterized under anechoic conditions on a finite baffle with respect to its off-axis frequency response.

Closing the gap towards super-long suspension bridges using computational morphogenesis.

Girder design for suspension bridges has remained largely unchanged for the past 60 years. However, for future super-long bridges, aiming at record-breaking spans beyond 3 km, the girder weight is a limiting factor. Here we report on a design concept, inspired by computational morphogenesis procedures, demonstrating possible weight savings in excess of 28 percent while maintaining manufacturability.

Giga-voxel computational morphogenesis for structural design.

In the design of industrial products ranging from hearing aids to automobiles and aeroplanes, material is distributed so as to maximize the performance and minimize the cost. Historically, human intuition and insight have driven the evolution of mechanical design, recently assisted by computer-aided design approaches. The computer-aided approach known as topology optimization enables unrestricted design freedom and shows great promise with regard to weight savings, but its applicability has so far been limited to the design of single components or simple structures, owing to the resolution limits of current optimization methods.

Infill Optimization for Additive Manufacturing-Approaching Bone-Like Porous Structures.

Porous structures such as trabecular bone are widely seen in nature. These structures are lightweight and exhibit strong mechanical properties. In this paper, we present a method to generate bone-like porous structures as lightweight infill for additive manufacturing.