This thesis explores the design, characterization, and experimental testing of energy absorbing mechanical metamaterials with a focus on bistable triangle structures. A comprehensive literature review categorizes existing energy absorbing metamaterials based on complexity, bistability, and energy dissipation characteristics, revealing significant research gaps in quantifying and correlating design parameters to performance metrics, particularly the energy absorption. To address these gaps, a novel, cost-effective, and repeatable dynamic impact tester was developed, inspired by the Charpy impact test but optimized for energy absorption testing. Using this dynamic tester and quasi static tests, a series of 3D-printed bistable triangular flexures were evaluated. Results highlight the influence of geometrical parameters such as flexure angle, thickness, and flexure geometry on energy dissipation. Notably, samples with a high angle demonstrated a high energy dissipation compared to low angle flexures. The findings establish foundational design guidelines and provide insights into optimizing mechanical metamaterials for applications in reusable, impact-absorbing systems.