Optimization of Composite Fracture Properties: Method, Validation, and Applications

Abstract

A paradigm in nature is to architect composites with excellent material properties compared to its constituents, which themselves often have contrasting mechanical behavior. Most engineering materials sacrifice strength for toughness, whereas natural materials do not face this tradeoff. However, biology's designs, adapted for organism survival, may have features not needed for some engineering applications. Here, we postulate that mimicking nature's elegant use of multimaterial phases can lead to better optimization of engineered materials. We employ an optimization algorithm to explore and design composites using soft and stiff building blocks to study the underlying mechanisms of nature's tough materials. For different applications, optimization parameters may vary. Validation of the algorithm is carried out using a test suite of cases without cracks to optimize for stiffness and compliance individually. A test case with a crack is also performed to optimize for toughness. The validation shows excellent agreement between geometries obtained from the optimization algorithm and the brute force method. This study uses different objective functions to optimize toughness, stiffness and toughness, and compliance and toughness. The algorithm presented here can provide researchers a way to tune material properties for a vast number of engineering problems by adjusting the distribution of soft and stiff materials.

Advanced Structural Materials by Bioinspiration

“…Recently, 3D‐printing has been widely used as a proof‐of‐concept to prove the validity of biomimetic design principles in delivering damage‐tolerant engineering materials. In particular, by using a multimaterial 3D printer (Objet 500 Connex3, Stratasys Ltd.), Buehler and co‐workers have explored different aspects of biomimetic design (Figure ) . In addition to the well‐known advantages of additive manufacturing (e.g., rapidity and versatility), this printing technology provides the possibility of simultaneously printing a multitude of materials with varying mechanical properties, ensuring good interfacial adhesion between the constituent materials, and reaching a micrometer resolution.…”

“…However, such structures might not be optimized for mechanical properties. By adopting pure polymers with contrasting properties as building blocks, Gu et al designed and printed new composites optimized and tuned for specific properties (e.g., damage tolerance). They developed an optimization algorithm to guide the design phase and combined simulations and experiments to prove the validity of the design.…”

Stress Cracking Behavior of Interstitial Matrix and Cement Line Interface Deflection

“…Thus, the accuracy of the following iteration results may be increase as the convergence test is performed on the FE model of osteon. The size of element may also be reduced [14].…”

Bioinspired hierarchical composite design using machine learning: simulation, additive manufacturing, and experiment

“…This is done in practice by augmenting biomimicry using optimization with application-specific objective functions. [18][19][20][21][22] Optimization, however, does not come without high computational expense as the necessary design space to be considered is vast. Specifically, there are many potential structures that can be arranged in numerous ways over various length scales, and so the number of possible configurations rapidly approaches astronomical values.…”