Session: 07-07-02: Computational Modeling in Biomedical Applications II

Paper Number: 164630

Enhancing Breast Prosthesis Design: A Study on Infill Patterns and Mechanical Performance 

This study investigates the optimal infill pattern for the additive manufacturing (AM) of external breast prostheses, with a focus on mechanical performance, functionality, and user comfort. Additive manufacturing offers significant advantages in the development of customized prosthetic solutions, allowing for patient-specific geometries and material properties tailored to individual needs. However, the choice of infill structure plays a crucial role in determining the mechanical behavior, durability, and overall comfort of the final prosthesis. This research aims to identify the most suitable infill pattern and percentage by evaluating deformation and resistance requirements through mathematical modeling and computer simulations.

To achieve this, a comprehensive mechanical characterization of cellular structures based on triply periodic minimal surfaces (TPMS) was conducted. TPMS structures have been widely studied for their superior mechanical properties, including high strength-to-weight ratios and tunable elasticity, making them ideal candidates for prosthetic applications. Several TPMS-based infill geometries were examined, with a primary focus on the Gyroid structure, known for its ability to provide a balance between flexibility and mechanical strength.

Finite element analysis (FEA) simulations were employed to validate the proposed mathematical model. These simulations incorporated various standard breast cup sizes, fabrication materials, structure types, and infill percentages to assess mechanical performance under realistic loading conditions. The results demonstrated a displacement error of less than 10%, indicating strong agreement between the simulations and theoretical predictions. The Gyroid structure was found to offer the best combination of mechanical strength and flexibility, ensuring both durability and user comfort. This characteristic is particularly important for breast prostheses, as they must mimic the mechanical properties of natural tissue while maintaining long-term structural integrity.

Furthermore, to optimize the additive manufacturing process and improve material efficiency, a relationship between breast cup size and infill percentages was established for flexible resin. This approach was chosen due to its ability to achieve the necessary mechanical properties while reducing material consumption compared to elastic resin, making the fabrication process more sustainable and cost-effective.

The findings of this study highlight the potential of additive manufacturing for the development of external breast prostheses that closely mimic the mechanical behavior of natural breast tissue. By leveraging advanced infill designs, particularly TPMS-based structures, it is possible to enhance the functional and aesthetic qualities of prosthetic devices, ultimately improving the quality of life for users. Future research will focus on experimental validation through physical testing and patient feedback to further refine the proposed designs and ensure their real-world applicability.

Presenting Author: Carlos G. Helguero ESPOL Polytechnic University

Presenting Author Biography: Carlos G. Helguero (Member, ASME) is a full-time Mechanical Engineering Department (FIMCP) professor at ESPOL Polytechnic University. He received his PhD in Mechanical Engineering, in the biomedical engineering area, from SUNY Stony Brook University – USA.
His research interests include applications of additive manufacturing to solve biomedical engineering problems. In this field, among his projects is the development of 3D-printed surgical guides for osteosarcoma-related surgeries. He is also interested in studying the feasibility of applying 3D-printed medical models for surgery planning and education. Moreover, he is developing a methodology to design and 3D-print orthosis for member immobilization. Finally, he is currently conducting a project to create a 3D-printed breast prosthesis for women under the mastectomy procedure.

Authors:

Jose Cansing ESPOL Polytechnic University
Gabriel Murillo ESPOL Polytechnic University
Jorge Amaya ESPOL Polytechnic University
Fausto Maldonado ESPOL Polytechnic University
Carlos Saldarriaga ESPOL Polytechnic University
Carlos G. Helguero ESPOL Polytechnic University