FAILURE ANALYSIS OF ADDITIVELY MANUFACTURED COMPOSITE MATERIALS USING DIGITAL IMAGE CORRELATION

Author

• Ana Laura Tanda Ocampo, Southern Illinois University CarbondaleFollow

Date of Award

8-1-2026

Degree Name

Master of Science

Department

Mechanical Engineering

First Advisor

Nilufar, Sabrina

Abstract

Additive manufacturing (AM) enables the fabrication of complex, lightweight structures that are difficult to produce using conventional manufacturing methods. Honeycomb and Triply Periodic Minimal Surface (TPMS) gyroid lattices are examples of structures that can provide high strength-to-weight ratios, energy absorption, and improved damage resistance. Because of these characteristics, these structures are relevant for advanced engineering applications in the aerospace, automotive, and construction industries, where lower weight and higher mechanical performance are both critical. This thesis analyzes the compressive behavior and failure mechanisms of 3D-printed honeycomb and TPMS gyroid sandwich structures fabricated by vat photopolymerization. Two types of samples are examined: neat resin and resin reinforced with hollow glass microballoons.Quasi-static uniaxial compression tests were performed on the honeycomb and TPMS structures. For the TPMS specimens, both horizontal and vertical surface patterns were evaluated to clarify deformation behavior and compare the effect of microballoon reinforcement. Additionally, Digital Image Correlation (DIC), a non-contact Non-Destructive Evaluation (NDE) method, was used to capture full-field displacement and strain distributions, providing insights into shear band formation, strain localization, and progressive failure. Furthermore, a macroscopic homogenized Finite Element Analysis (FEA) model was developed in ANSYS and calibrated using experimentally derived material properties to predict the structural response and compare the numerical strain contours with the experimental DIC maps. The results indicate that lattice geometry strongly influences the mechanical effect of microballoon reinforcement. In the strut-based honeycomb specimens, microballoons increased stiffness and peak compressive stress, with an enhancement factor of 1.11 in compressive modulus. Whereas in the continuous TPMS gyroid specimens, they reduced peak strength, retaining only 54.9% of the neat modulus, while promoting a more compliant, damage-tolerant response. The comparison between ANSYS strain contours and DIC strain maps support the use of a homogenized computational approach to predict macroscopic deformation behavior of these printed composite lattices. These findings contribute to the development of lightweight composites with tailored mechanical performance for engineering applications.