A Variational Beam Model for Failure of Cellular and Truss‐Based Architected Materials

Karapiperis, Konstantinos; Radi, Kaoutar; Wang, Zifan; Kochmann, Dennis M.

doi:10.1002/adem.202300947

Cited by 3 publications

(1 citation statement)

References 77 publications

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“…Mechanical metamaterials are usually designed from the geometric repetition of a unit cell in the different directions of the space, creating more complex structures [24][25][26], such as honeycomb sandwiches and plates or other hierarchical structures [27][28][29][30]. Mechanical metamaterials present new or extreme mechanical properties [31,32], like extreme stiffness/density ratios [33][34][35][36], customizable and tunable auxetic behavior [37][38][39], high specific plastic dissipation or fracture propagation improvements [40][41][42][43]. These are also dependent on the different metamaterial scales addressed (macro-/micro-/nano-structures) [44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Defects in Finite Elements to Model Effective Mechanical Properties of Metamaterial Cells Printed by Selective Laser Melting

Vera-Rodríguez,

Moreno-Corrales,

Marín-González

et al. 2024

Sustainability

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Additively printed mechanical metamaterial structures optimize material, energy and waste, producing more sustainable products. Their introduction in the production workflow depends on having proper tools for accurately predicting their performance. However, the additive manufacturing process incorporates significant defects which result in an important change of the effective properties of the metamaterial cell. Finite element predictions using perfect geometries and nominal base material properties result in important errors which may require excessive uncertainty-related safety design margins. This work presents a methodology to introduce the effect of the most common defects in finite element models to compute the effective mechanical response of different metamaterials printed by Selective Laser Melting. It is shown that even at elastic infinitesimal strains, the defects produce an important change in the effective mechanical capabilities of the metamaterial, which also depend on the type of the metamaterial cell studied and on the type and magnitude of defects. With the proposed methodology, which incorporates the distribution of defects in the finite element model, the predicted mechanical properties of the metamaterial better match the experimental ones. It is shown that the initial discrepancies in the order of 100% are reduced to an order of 5%.

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Section: Introductionmentioning

confidence: 99%

Incorporation of Defects in Finite Elements to Model Effective Mechanical Properties of Metamaterial Cells Printed by Selective Laser Melting

Vera-Rodríguez,

Moreno-Corrales,

Marín-González

et al. 2024

Sustainability

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A mixed-order quasicontinuum approach for beam-based architected materials with application to fracture

Kraschewski,

Phlipot,

Kochmann

2024

Comput Mech

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Predicting the mechanics of large structural networks, such as beam-based architected materials, requires a multiscale computational strategy that preserves information about the discrete structure while being applicable to large assemblies of struts. Especially the fracture properties of such beam lattices necessitate a two-scale modeling strategy, since the fracture toughness depends on discrete beam failure events, while the application of remote loads requires large simulation domains. As classical homogenization techniques fail in the absence of a separation of scales at the crack tip, we present a concurrent multiscale technique: a fully-nonlocal quasicontinuum (QC) multi-lattice formulation for beam networks, based on a conforming mesh. Like the original atomistic QC formulation, we maintain discrete resolution where needed (such as around a crack tip) while efficiently coarse-graining in the remaining simulation domain. A key challenge is a suitable model in the coarse-grained domain, where classical QC uses affine interpolations. This formulation fails in bending-dominated lattices, as it overconstrains the lattice by preventing bending without stretching of beams. Therefore, we here present a beam QC formulation based on mixed-order interpolation in the coarse-grained region—combining the efficiency of linear interpolation where possible with the accuracy advantages of quadratic interpolation where needed. This results in a powerful computational framework, which, as we demonstrate through our validation and benchmark examples, overcomes the deficiencies of previous QC formulations and enables, e.g., the prediction of the fracture toughness and the diverse nature of stress distributions of stretching- and bending-dominated beam lattices in two and three dimensions.

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A conforming frictional beam contact model

Karapiperis,

Widmer,

Pescialli

et al. 2024

Computer Methods in Applied Mechanics and Engineering

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A Variational Beam Model for Failure of Cellular and Truss‐Based Architected Materials

Cited by 3 publications

References 77 publications

Incorporation of Defects in Finite Elements to Model Effective Mechanical Properties of Metamaterial Cells Printed by Selective Laser Melting

Incorporation of Defects in Finite Elements to Model Effective Mechanical Properties of Metamaterial Cells Printed by Selective Laser Melting

A mixed-order quasicontinuum approach for beam-based architected materials with application to fracture

A conforming frictional beam contact model

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