Experimental Study on Digital Light Processing to Manufacture Elastomeric Models with Embedded Fluorescent Particles for Strain Measurement

open_access
Open Access
Author:
Daghir, Joseph
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Guhaprasanna Manogharan, Thesis Supervisor
Jean-Michel Mongeau, Thesis Honors Advisor
Keywords:
Additive Manufacturing
Digital Light Processing
DLP
Fluorescent Particles
Embedded Particles
Abstract:
This thesis explores the possibility of using digital light processing, a photopolymerization-based additive manufacturing process, for producing elastomeric models with embedded fluorescent particles. Using particle tracking velocimetry (PTV), these particles are intended as tracers for a detailed and volumetric assessment of strain within the printed model's walls. While the proposed manufacturing process has potential for various applications, this project specifically evaluates its suitability for biomedical models, with a particular focus on left ventricles. Considering this focus, the material used in this project was intended to mimic soft tissue and its common experimental substitutes, such as polydimethylsiloxane (PDMS). To evaluate whether the proposed manufacturing process was suitable for this application, three experiments were conducted. First, tensile tests were conducted to determine the impact of particle concentration on elastic modulus, ultimate tensile strength, and elongation at break. Next, particle dispersion was evaluated to determine if the concentration of particles shifted throughout the print. Lastly, a measurement of refractive index (RI) was obtained to ensure that the model was optically compatible with blood analogs. Using Student’s t-tests, the addition of particles proved to make a significant impact on the mechanical properties, but in varying amounts for each concentration. Highlighting the importance of matching particle density to resin density, the particle dispersion experiment revealed that the particles slowly floated during the print. Supporting the use of this manufacturing process for the intended application, the RI was found within the acceptable range for blood analogs. Although new materials may require recharacterization, this novel additive process shows promise for advancing the capabilities of PTV-based strain tracking.