Date Approved

8-18-2025

Graduate Degree Type

Thesis

Degree Name

Engineering (M.S.E.)

Degree Program

School of Engineering

First Advisor

Dr. Yunju Lee

Second Advisor

Dr. Sunghwan Joo

Third Advisor

Dr. Samhita Rhodes

Academic Year

2024/2025

Abstract

Silicone breast implants are commonly used in breast augmentation and reconstruction procedures. Mentor introduced two newer models of silicone gel-filled implants, the MemoryGelTM Xtra and MemoryGelTM Boost, designed to increase the gel fill and projection of the implants while reducing wrinkling and rippling of the shell. Modifications to the shape and fill of these implants may result in different mechanical responses under compressive or impact loading conditions. To investigate whether these structural differences influence implant behavior, in vitro drop testing and finite element analysis (FEA) simulations were conducted, focusing on impact forces, internal stresses, and deformation patterns experienced by the implants. Compression and tensile testing of implants and their components were done to inform the material models for FEA.

Statistical analysis of the drop test data showed that, for the medium and large implants, significant differences existed between the MemoryGelTM implants and both the Xtra and Boost implants, however, the maximum forces of the Xtra and Boost implants did not differ significantly. The small and medium Xtra implants consistently showed greater equivalent von Mises and maximum principal stresses. In the large size group, the Boost implants showed larger stress, whereas for all sizes, the MemoryGelTM implants showed the lowest stresses. The stress distributions for both equivalent and maximum principal stress were similar for all implant types. Equivalent stress was centralized within the implants, whereas maximum principal stress (tensile) was localized on the surface of the implant.

Drop testing results indicated that increased fill and projection in the Xtra and Boost implants affected the applied forces under impact conditions. This showed that implant design influenced the response of silicone implants to mechanical loads. Despite MemoryGelTM showing higher applied forces in the horizontal orientation, the Xtra implants experienced greater internal stresses—suggesting that highly filled designs may be more vulnerable to failure under compressive loads.

Understanding the mechanical behavior of these implant models under impact loading is critical for evaluating rupture risk and potential failure mechanisms. This study aims to provide insight into how design modifications affect implant safety and performance, offering a scientific basis for clinical considerations and future product development.

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