As global ambient temperatures continue to rise, with the highest recorded annual averages since 1850 being within the last ten years, problems emerge for species exhibiting temperature-dependent sex determination. This is the process by which the sex of an animal’s embryo is determined based on the temperature of environment in which it is incubated, which can result in skewed sex ratios within a population like in the case of the critically endangered Hawksbill Sea Turtles (Eretmochelys imbricata). Reportedly, 85-95% of Hawksbills sampled in the wild are currently female [3]. This sex-imbalance can negatively impact the species’ ability to procreate, leading to the potential for extinction. Currently, no viable, long-term solutions exist to effectively and safely cool sea turtle eggs while still keeping them within their natural habitat. This research proposes the creation of sea turtle egg incubators designed to achieve a temperature range that will produce a higher percentage of male hatchlings to help rectify this imbalance in habitats heavily affected by climate change. These incubators are designed to be affordable, easy to build and, most importantly, safe for the sea turtle eggs. Three-month-long temperature trials for the incubator were conducted in Jamaica with conservationist community partners at Oracabessa Bay Sea Turtle Project. Results showed that this incubator is not only easy to manufacture and use, but that it successfully regulates the temperature range in favor of more male hatchlings, while also increasing the emergence rate of the hatchlings from 70% in natural nests to over 80%. During one of the hottest months in Jamaica, the incubator, deployed without water changes, doubled the predicted percentage of males produced by natural nests. When provided with cool water changes the incubator quintupled this value. Throughout the months of August to October, the incubator achieved a temperature range that is predicted to produce 85-99% male hatchlings, thus counteracting the feminization phenomenon occurring in nature.

Abstract

Foams, widely used in packaging, insulation, protective gear, and medical implants, are versatile materials but mechanically inefficient due to their bending-dominated microstructure, leading to an exponential loss of stiffness and strength at low relative densities. Architected materials address this limitation through engineered microstructures that achieve near-linear scaling of properties with relative density. However, truss- and plate-based designs suffer from stress concentrations, while shell-based architectures, though more mechanically efficient, remain highly sensitive to defects and are challenging to fabricate at scale via additive manufacturing. Spinodal architected materials, derived from scalable spinodal decomposition processes, offer a promising alternative with aperiodic, double-curvature microstructures that enhance mechanical efficiency at low relative densities. Nevertheless, their behavior beyond the elastic regime remains largely unexplored. This thesis investigates the nonlinear mechanics of spinodal architected materials by combining a comprehensive experimental dataset with computational modeling. A total of 107 unique morphologies were fabricated and subjected to uniaxial compression along three principal directions, resulting in a dataset of 321 stress-strain curves. Morphologies were generated via simulated spinodal decomposition, allowing controlled variation of anisotropy. Explicit finite element simulations, validated against experimental data, revealed that plastic energy dissipation dominates the large-strain mechanical response. To quantitatively link local morphology to global mechanical behavior, we introduce the Normal Participation Factor (NPF) — a scalar geometric parameter that captures the alignment between surface normals and the loading direction. We demonstrate that the NPF is a material-agnostic proxy for equivalent plastic strain and is linearly correlated with the total energy dissipated during deformation. Combining insights from both experiments and simulations, we establish the NPF as a first-order predictive tool for mechanical behavior under large strains, enabling structure-property predictions without reliance on costly simulations or extensive experimental testing. Altogether, this work lays the foundation for developing finite-strain structure-property relationships in spinodal architected materials, advancing their potential for real-world applications.