Impact Resistance and Specific Energy Absorption Efficiency Limits of Periodic Cellular Solids

Bernard, Autumn R.

doi:10.2514/6.2022-1093

Cited by 3 publications

(8 citation statements)

References 52 publications

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“…where, in the numerical model, the stress is obtained from the impact force between the impactor and lattice divided by the surface area of the upper surface of the lattice unit cell envelope, and the strain is obtained from the displacement of the uppermost surface of the lattice divided by the lattice unit cell height, a method commonly used in the literature [25,46,47]. Densification Strain.…”

Section: Data Analysis and Crashworthiness Parametersmentioning

confidence: 99%

Crashworthiness of 3D Lattice Topologies under Dynamic Loading: A Comprehensive Study

Bernard,

ElSayed

2024

Materials

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Periodic truss-based lattice materials, a particular subset of cellular solids that generally have superior specific properties as compared to monolithic materials, offer regularity and predictability that irregular foams do not. Significant advancements in alternative technologies—such as additive manufacturing—have allowed for the fabrication of these uniquely complex materials, thus boosting their research and development within industries and scientific communities. However, there have been limitations in the comparison of results for these materials between different studies reported in the literature due to differences in analysis approaches, parent materials, and boundary and initial conditions considered. Further hindering the comparison ability was that the literature generally only focused on one or a select few topologies. With a particular focus on the crashworthiness of lattice topologies, this paper presents a comprehensive study of the impact performance of 24 topologies under dynamic impact loading. Using steel alloy parent material (manufactured using Selective Laser Melting), a numerical study of the impact performance was conducted with 16 different impact energy–speed pairs. It was possible to observe the overarching trends in crashworthiness parameters, including plateau stress, densification strain, impact efficiency, and absorbed energy for a wide range of 3D lattice topologies at three relative densities. While there was no observed distinct division between the results of bending and stretching topologies, the presence of struts aligned in the impact direction did have a significant effect on the energy absorption efficiency of the lattice; topologies with struts aligned in that direction had lower efficiencies as compared to topologies without.

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Section: Data Analysis and Crashworthiness Parametersmentioning

confidence: 99%

Crashworthiness of 3D Lattice Topologies under Dynamic Loading: A Comprehensive Study

Bernard,

ElSayed

2024

Materials

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“…Figure 14(c) provides an example as applied within a lattice material, the dimensions of which are defined in the following paragraphs. For an arbitrary cross-section, the following variables are used to define its rectangular envelope: width, 𝐵; height, 𝐻; Area, 𝐴 𝐷 = 𝐵𝐻; and Second moment of area, 𝐼 𝐷 = 𝐵𝐻 3…”

Section: Cross-section Basicsmentioning

confidence: 99%

“…The geometric efficiency, 𝜆, describes how efficiently the shape fills its envelope, and can fall along the interval of [0,3], depending on the cross-sectional shape [172,174].…”

Section: Shape Transformersmentioning

confidence: 99%

“…General forms of equations used to generate TPMS lattices, as in Figure A.5, have been highlighted in Table A. 3, where additional variations of the equations, as seen in the investigated literature, have also been provided. Note that these equations capture the general form used in literature (e.g., sines and cosines) and do not necessarily reflect the exact form presented in the reference source, particularly in relation to the level-set values utilized, since they were put in the form 𝑓( , 𝑦, 𝑧) − 𝐶( , 𝑦, 𝑧) = 0, which is required for MSLattice [273].…”

Section: A41 Topologymentioning

confidence: 99%

“…For a great majority of the work with periodic strut-based lattice materials, especially in relation to EA capabilities, the cross-section of a strut is both circular and cylindrical (i.e., non-tapered) [2,46,114,120,132,133,135,139,150,[187][188][189][190][191]. However, there is some research in the realm of periodic lattices with non-circular and non-cylindrical struts [93][94][95][96][97]171,[192][193][194].…”

Section: Introductionmentioning

confidence: 99%

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Multiscale Impact Mechanics of Additively Manufactured Periodic Cellular Solids

Bernard

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Cellular materials are well known to have superior weight-specific properties, including Energy Absorption (EA) capabilities, as compared to solid, monolithic materials. Regular periodic lattice materials, which are a subset of cellular materials, are I would like to begin by thanking my supervisor Dr. Mostafa El Sayed, without whom I would have been unable to see this work through to completion. His persistent push to challenge me helped me grow academically and I truly appreciate all of his guidance and encouragement throughout the entire thesis process, which can be rather tense during the best of times but was a unique process to start, continue, and end during a pandemic, which was an ever-present looming shadow.I would also like to acknowledge the guidance of Dr. Muhammet Yalcin, with whom I had the pleasure of working with in 2022 and with whom I am looking forward to finishing the publication of a few additional papers from our work together.I would also like to sincerely thank BOMBARDIER Aerospace, Montreal, together with MITACS, Canada, for their financial support of this research.Additionally, thank you to my peers: Padmassun for his quick and detailed Python and regex help; and Ariane for her Ansys SpaceClaim guidance, supportive words, and the helpful encouragement to simply write a bit of code to do my repetitive tasks automatically.Thank you to my family -mom, dad, and Kael -for their continual support throughout this seemingly unending academic journey. I also owe a great deal of thanks to my close friends -A, S, K, and B -for all of the ways in which they supported me along this perilous road: countless phone and video chats; brunches, bubble tea excursions, dinners, and long walks to help me get out of my apartment; watching cringe TV shows and sharing in my learning of crochet as stress-relievers; passing along their vi ramen recipes that I can't believe I've missed out on for so long; and for simply sticking around.I would also like to thank my therapist -who knows who she is -for her constant support.And lastly, the following events go fully unacknowledged, for they did not positively contribute to my physical nor mental health, cannot be said to have aided any forward progress of this thesis whatsoever and, without them, I surely would have finished sooner: the COVID-19 pandemic and contracting COVID-19; and the passing of my childhood puppy. vii

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Crashworthiness investigations for 3D printed multi-layer multi-topology carbon fiber nylon lattice materials

Bernard,

Yalcin,

ElSayed

2024

Journal of Reinforced Plastics and Composites

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Cellular solids have superior energy absorption capabilities as compared to monolithic materials. Within this category of materials, lattice materials are of particular interest since their periodicity offers repeatable – and thus predictable – behavior. In combination with the advancements in additive manufacturing technologies, these lattice materials can be highly customized for a desired response. In this paper, the crashworthiness of unique multi-layer, multi-topology (MLMT) lattices is investigated. First, the nylon-carbon fiber composite material properties within a developed numerical model were tuned based on strut orientation. Then, the response of single-layer and three-layer cubic and octet lattices was investigated, where all lattices were designed with a relative density of 30%. Following the characterization of single-topology lattices, the response of MLMT lattices were investigated. Stress-strain, efficiency-strain, and multiple crashworthiness parameter data was collected for all lattices to facilitate in the comparison of those lattices. It was found that, experimentally, the unique MLMT lattices did not absorb more energy than their constituent layers combined, though modifications to the interface between layers could increase the energy absorption capability; the prediction of energy absorption of the MLMT lattices based on constituent layers was similar to actual numerical results. As all lattices were designed at the same relative density, the mass-specific energy absorption of the cubic-octet-cubic MLMT lattice (1.56 x103 J/kg) outperforms the single-topology octet lattice by 19% to 36% (1.15–1.31 x103 J/kg). While the octet-cubic-octet MLMT lattice (0.71 x103 J/kg) is outperformed by the single-topology cubic lattices (1.69–3.76 x103 J/kg), they see an increase of 59% to 77% in plateau stress (5.1–9.2 MPa) as compared to the MLMT lattice (2.1 MPa).

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Impact Resistance and Specific Energy Absorption Efficiency Limits of Periodic Cellular Solids

Cited by 3 publications

References 52 publications

Crashworthiness of 3D Lattice Topologies under Dynamic Loading: A Comprehensive Study

Crashworthiness of 3D Lattice Topologies under Dynamic Loading: A Comprehensive Study

Multiscale Impact Mechanics of Additively Manufactured Periodic Cellular Solids

Crashworthiness investigations for 3D printed multi-layer multi-topology carbon fiber nylon lattice materials

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