Metamaterials with engineered failure load and stiffness

By Sai Sharan Injeti, Chiara Daraio, Kaushik Bhattacharya. 2019

27 citations recorded by the source corpus.

Significance A structure that fails at large loads is expected to be dense and stiff. This is because in conventional materials failure load depends directly on stiffness and density. This paper shows that the addition of engineered internal stresses in truss-like structures allows decoupling of these properties, increasing the failure load 2-fold while maintaining constant the density and stiffness. A similar approach could also be used to control locations and paths of failure in architected materials. Architected materials or metamaterials have proved to be a very effective way of making materials with unusual mechanical properties. For example, by designing the mesoscale geometry of architected materials, it is possible to obtain extremely high stiffness-to-weight ratio or unusual Poisson’s ratio. However, much of this work has focused on designing properties like stiffness and density, and much remains unknown about the critical load to failure. This is the focus of the current work. We show that the addition of local internal prestress in selected regions of architected materials enables the design of materials where the critical load to failure can be optimized independently from the density and/or quasistatic stiffness. We propose a method to optimize the specific load to failure and specific stiffness using sensitivity analysis and derive the maximum bounds on the attainable properties. We demonstrate the method in a 2D triangular lattice and a 3D octahedral truss, showing excellent agreement between experimental and theoretical results. The method can be used to design materials with predetermined fracture load, failure location, and fracture paths.

Subfields: Civil and Structural Engineering, Mechanical Engineering

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Civil and Structural Engineering

1. L. Catherine Brinson
2. Alexander C. Ogren
3. Chiara Daraio
4. Zhi Chen
5. Cynthia Rudin

In Mechanical Engineering

1. L. Catherine Brinson
2. Chiara Daraio

Citations in the corpus

• How to See Hidden Patterns in Metamaterials with Interpretable Machine Learning (2021, background): “For example, compared to conventional composite materials, mechanical metamaterials can be surprisingly lightweight and strong [53, 65], can have controllable fracture toughness [22], and can be highly energy- and vibration-absorptive [3, 17, 35, 42, 43].”