Metamaterials with engineered failure load and stiffness

Area of Science:

• Materials Science
• Mechanical Engineering
• Solid Mechanics

Background:

• Architected materials and metamaterials offer tunable mechanical properties through mesoscale geometry design.
• Existing research primarily focuses on optimizing stiffness and density, with limited understanding of failure load.
• The critical load to failure is a crucial parameter for structural integrity and material performance.

Purpose of the Study:

• To investigate the role of local internal prestress in architected materials for optimizing failure load.
• To develop a method for independently controlling the critical load to failure and stiffness.
• To establish theoretical bounds for attainable mechanical properties in prestressed architected materials.

Main Methods:

• Introduction of local internal prestress in specific regions of architected materials.
• Application of sensitivity analysis to optimize specific load to failure and specific stiffness.
• Derivation of maximum bounds for achievable material properties.
• Experimental and theoretical validation using 2D triangular lattices and 3D octahedral trusses.

Main Results:

• Internal prestress enables independent optimization of critical load to failure from density and quasistatic stiffness.
• The proposed method successfully optimizes specific load to failure and specific stiffness.
• Demonstrated excellent agreement between theoretical predictions and experimental results in lattice and truss structures.
• The method allows for predetermined fracture load, failure location, and fracture path control.

Conclusions:

• Local internal prestress is a powerful tool for designing architected materials with tailored failure characteristics.
• The developed method provides a pathway to engineer materials with predictable and controllable failure modes.
• This approach has significant implications for the design of lightweight, high-performance structures with enhanced safety and reliability.