Elastic and plastic characterization of a new developed additively manufactured functionally graded porous lattice structure: Analytical and numerical models

Mahbod, Mahshid; Asgari, Masoud

doi:10.1016/j.ijmecsci.2019.02.041

Cited by 96 publications

(35 citation statements)

References 58 publications

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“…Generally, the − curve of cellular structures tends to show three characteristic regions which in its entireness describes the elastic and plastic structural performance [119]. The first characteristics regions can be speared into linear and nonlinear elastic deformation, where a proportional − relationship is followed by a non-linear region ending in a peak stress value referred to as the ultimate strength ( ) [120]. This is usually followed by a drop-in stress to the plateau region where stress fluctuations or serrations maybe observed [121].…”

Section: Elastic-plastic Performancementioning

confidence: 99%

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Arjunan

Demetriou

Baroutaji

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

122

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Critically engineered stiffness and strength of a scaffold are crucial for managing maladapted stress concentration and reducing stress shielding. At the same time, suitable porosity and permeability are key to facilitate biological activities associated with bone growth and nutrient delivery. A systematic balance of all these parameters are required for the development of an effective bone scaffold. Traditionally, the approach has been to study each of these parameters in isolation without considering their interdependence to achieve specific properties at a certain porosity. The purpose of this study is to undertake a holistic investigation considering the stiffness, strength, permeability, and stress concentration of six scaffold architectures featuring a 68.46-90.98% porosity. With an initial target of a tibial host segment, the permeability was characterised using Computational Fluid Dynamics (CFD) in conjunction with Darcy's law. Following this, Ashby's criterion, experimental tests, and Finite Element Method (FEM) were employed to study the mechanical behaviour and their interdependencies under uniaxial compression. The FE model was validated and further extended to study the influence of stress concentration on both the stiffness and strength of the scaffolds. The results showed that the pore shape can influence permeability, stiffness, strength, and the stress concentration factor of Ti6Al4V bone scaffolds. Furthermore, the numerical results demonstrate the effect to which structural performance of highly porous scaffolds deviate, as a result of the Selective Laser Melting (SLM) process. In addition, the study demonstrates that stiffness and strength of bone scaffold at a targeted porosity is linked to the pore shape and the associated stress concentration allowing to exploit the design freedom associated with SLM.

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Section: Elastic-plastic Performancementioning

confidence: 99%

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Arjunan

Demetriou

Baroutaji

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

122

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“…Bone tissue implants need to have a similar stiffness to the surrounding bone, in order to avoid stress shielding and to improve bone regeneration (Ganadhiepan et al, 2019a;Ghimire et al, 2019;Miramini et al, 2018;Zhang¹ et al, 2013), yet they are frequently manufactured from stainless steel or titanium, which is much stiffer (Miramini et al, 2015). Many different studies have created FGBMs by varying the size of the lattice unit cell throughout the material to alter the stiffness of the scaffold in different locations (Mahbod and Asgari, 2019;Torres et al, 2016;Zhang et al, 2019). Ayatollahi et al (2019) have proposed a 3-phase ceramic based FGBM, which uses HA, alumina or zircona, and titanium all within the same component to provide different material properties in different locations on a knee implant.…”

Section: Improving the Mechanical Properties Of Implants Using Ammentioning

confidence: 99%

The status and challenges of replicating the mechanical properties of connective tissues using additive manufacturing

Miramini

Fegan

Green

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

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Link to publication on Research at Birmingham portal General rights Unless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law. • Users may freely distribute the URL that is used to identify this publication. • Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research. • User may use extracts from the document in line with the concept of 'fair dealing' under the Copyright, Designs and Patents Act 1988 (?) • Users may not further distribute the material nor use it for the purposes of commercial gain. Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

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“…RPSs and FGPSs consisting of double pyramid dodecahedron unit cells are indicated in Figure 1. The unit cell which has been presented by the authors 25 named double pyramid dodecahedron. It is an extension on some previously studied cells based on truncated cube and octahedral.…”

Section: Materials and Modelsmentioning

confidence: 99%

Architected functionally graded porous lattice structures for optimized elastic-plastic behavior

Mahbod

Asgari

Mittelstedt

2020

Proceedings of the Institution of Mechanical Engineers, Part L:

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In this paper, the elastic–plastic mechanical properties of regular and functionally graded additively manufactured porous structures made by a double pyramid dodecahedron unit cell are investigated. The elastic moduli and also energy absorption are evaluated via finite element analysis. Experimental compression tests are performed which demonstrated the accuracy of numerical simulations. Next, single and multi-objective optimizations are performed in order to propose optimized structural designs. Surrogated models are developed for both elastic and plastic mechanical properties. The results show that elastic moduli and the plastic behavior of the lattice structures are considerably affected by the cell geometry and relative density of layers. Consequently, the optimization leads to a significantly better performance of both regular and functionally graded porous structures. The optimization of regular lattice structures leads to great improvement in both elastic and plastic properties. Specific energy absorption, maximum stress, and the elastic moduli in x- and y-directions are improved by 24%, 79%, 56%, and 9%, respectively, compared to the base model. In addition, in the functionally graded optimized models, specific energy absorption and normalized maximum stress are improved by 64% and 56%, respectively, in comparison with the base models.

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Elastic and plastic characterization of a new developed additively manufactured functionally graded porous lattice structure: Analytical and numerical models

Cited by 96 publications

References 58 publications

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

The status and challenges of replicating the mechanical properties of connective tissues using additive manufacturing

Architected functionally graded porous lattice structures for optimized elastic-plastic behavior

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