Concepts for enhanced energy absorption using hollow micro-lattices

By A. G. Evans, M. He, V. Deshpande, J. W. Hutchinson, A. J. Jacobsen, W. Carter. 2010

226 citations recorded by the source corpus.

Abstract We present a basic analysis that establishes the metrics affecting the energy absorbed by multilayer cellular media during irreversible compaction on either a mass or volume basis. The behaviors at low and high impulse levels are distinguished through the energy dissipated in the shock. The overall mass of an energy absorbing system (comprising a cellular medium and a buffer) is minimized by maximizing the non-dimensional dissipation per unit mass parameter for the cellular medium, Λ ≡ U m ρ s / σ Y , where Um is the dissipation per unit mass of the cellular medium, ascertained from the area under the quasi-static compressive stress/strain curve, σY the yield strength of the constituent material and ρs the density of the material used in the medium. Plots of Λ against the non-dimensional stress transmitted through the medium, σ tr / σ Y demonstrate the relative energy absorbing characteristics of foams and prismatic media, such as honeycombs. Comparisons with these benchmark systems are used to demonstrate the superior performance of micro-lattices, especially those with hollow truss members. Numerical calculations demonstrate the relative densities and geometric configurations wherein the lattices offer benefit. Experimental results obtained for a Ni micro-lattice with hollow members not only affirm the benefits, but also demonstrate energy absorption levels substantially exceeding those predicted by analysis. This assessment highlights the new opportunities that tailored micro-lattices provide for unprecedented levels of energy absorption for protection from impulsive loads.

Subfields: Mechanical Engineering, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/856502d1051b5c3515cfc8cc896c6a6610daa4c1

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In Mechanical Engineering

In Polymers and Plastics

Citations in the corpus

Design and Optimization of Lattice Structures: A Review (2020, background): “Energy absorbers [1,2,40–42], Heaters and heat exchangers [23,27,43–46], Engine hood [47], Biomedical implants [48–55], Wings [56], Gas turbine engine fan blades [57], Vibration absorber [58–61], Robotic system [62], Spacecraft and aircraft structures (i.e., fuselage, rib) [63–65].”
Strong and Tough Bioinspired Additive-Manufactured Dual-Phase Mechanical Metamaterial Composites (2021, background): “A case in point are Kagome and pyramidal lattice topologies with hollow trusses (Evans et al., 2010; Pingle et al., 2010), where their complicated geometries are still not feasible to fabricate in practice.”
Three-dimensional modelling of auxetic sandwich panels for localised impact resistance (2017, background): “Truss structures are characterised by a superior strength-to-weight ratio when compared with honeycomb and are more easily tailored for various applications [37].”
Mechanical performance of 3D printed interpenetrating phase composites with spinodal topologies (2021, background): “While quantitative assessment of impact performance requires high ‐ strain rate testing and are beyond the scope of this work, previous studies have demonstrated that impact performance ranking of cellular materials can be obtained by the quasi ‐ static experiments performed in this work [59,60].”
Drop weight impact behaviour of sandwich panels with metallic micro lattice cores (2013, background): “[24] analysed the impact performance of hollow nickel lattices, similar but on a larger scale to those discussed in [13].”
Metallic microlattice materials: a current state of the art on manufacturing, mechanical properties and applications (2016, background): “Impulse and blast resistant structure [72] - (a) Impulse from an air blast striking a solid buffer attached on top of a cellular medium, (b) The kinetic energy is converted to plastic deformation of the cellular medium and the resultant stress/strain response.”
Design of lattice structures with controlled anisotropy (2016, background): “Thus artificial cellular materials were developed and fabricated in the past decades on a large scale for a broad range of applications such as energy absorption (Evans et al., 2010), energy storage (Liu et al.”
A Numerical Study of Auxetic Composite Panels under Blast Loadings (2016, background): “Furthermore, the truss structure provides a higher strengthto-weight ratio when compared with a honeycomb structure and could be easily tailored for different applications [38,39].”