Mechanical Performance of Additively Manufactured Soft Materials for Ultrasound and Biomechanical Simulation

Abstract

Additive manufacturing has enabled the fabrication of anatomically accurate, customizable models for use in medical training and human-interactive technology development. Anatomical manikins produced through these techniques provide a safe, repeatable, and risk-free environment for users to practice and refine clinical procedures or test assistive robotic systems. However, challenges remain in achieving both anatomical fidelity and functional compliance. This thesis explores the design and fabrication of additively manufactured anthropomorphic manikins for two applications: physical simulation in point-of-care ultrasound (POCUS) training and passive validation for upper-limb exoskeletons. In Chapter 2, a passive hand and proximal interphalangeal (PIP) joint model was developed for biomechanical assessment of joint stiffness for future instrumentation using a J5 Digital Anatomy Printer (DAP). Anatomical fidelity was achieved through additive manufacturing, the PIP finger model, as well as void-infused thermoplastic polyurethane (TPU), was assessed based on ROM and elastic modulus to ensure appropriate joint compliance via uniaxial displacement, respectively. For POCUS training, a methodology is introduced in Chapter 3 to generate anatomically accurate right upper quadrant (RUQ) models from medical imaging using 3D Slicer. Tissue-mimicking Materials available on the J5 DAP were assessed for their echogenic properties through grayscale intensity analysis, highlighting both their potential and limitations for material tunability and echogenicity for ultrasound realism. The findings of this work address the feasibility of using 3D-printing techniques for soft material prints to fabricate anatomically and mechanically realistic manikins. These manikins have potential utility in enhancing ultrasound medical training and supporting the validation of rehabilitative hand exoskeletons.