A Computationally-Efficient Numerical Model to Characterize the Noise Behavior of Metal-Framed Walls

Biomed. Phys. Eng. Express

2019

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In order to reduce stress shielding following a segmental bone replacement surgery requires stiffness matching strategies between the host bone and the implant are required. Carefully engineered implant geometry that can mimic the mechanical performance of the host bone is required to achieve this. The development of Additive Layer Manufacturing (ALM) techniques such as Direct Metal Laser Sintering (DMLS) allows for the fabrication of complex geometries that can achieve targeted mechanical performance. Consequently, this work introduces a sheathed Ti6Al4V additively manufactured tibial implant that mimics the circumferential anatomy of the host bone. Performance evaluation of the implant was carried using experimental and numerical technique under axial compression. Furthermore, the influence of sheathing strategy and sheath thickness on the compressive performance of the implant is parametrically analysed. The results of this study shows a promising sheathed implant that can replace a defective tibia bone segment. The implant is superior to conventional porous implants as it allows for easy implantation in surgical operation and allows for the reduction of stress shielding.

Section: Discussionsupporting

confidence: 63%

Investigation of Ti64 sheathed cellular anatomical structure as a tibia implant

Vance

Bari

Biomed. Phys. Eng. Express

2019

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“…Furthermore, the validation study showed the current VoI represents an adequate ratio (internal/external) for the six UC arrangements considered in this study. Furthermore, a larger than required fluid domain will increase solution time, which is widely considered inefficient numerical modelling [86][87][88][89].…”

Section: Flow Simulation and Permeabilitymentioning

confidence: 99%

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Journal of the Mechanical Behavior of Biomedical Materials

Demetriou

Baroutaji

et al. 2020

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125

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.

“…Lightweight structures that combine high structural stiffness, energy absorption [1][2][3] and acoustic performance [4][5][6][7][8] are of interest to automotive, aerospace and the construction sectors. Automotive floor panels [9] and aerospace bulkheads [10] are examples of mechanical structures where the secondary function extends to providing adequate acoustic comfort.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Performance of Metallic Foams

Reference Module in Materials Science and Materials Engineering

Baroutaji

Praveen

et al. 2019

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Metallic foams are among the most promising class of materials due to their unique mechanical properties combining low mass with high stiffness, excellent energy absorption, and vibroacoustic damping. Consequently, noise control using methodically engineered metallic foams has received increased attention from both industrial and scientific community. Accordingly, this paper aims to present the mechanism of sound absorption along with the experimental and theoretical procedure that can be used to classify metallic foams. Additionally, the influence of design parameters on the resulting sound absorption coefficient of closed and opencell metallic foams are explored. While aluminium foams used to dominate the literature when it comes to acoustics, recent studies have reported Nickel-Inconel superalloy and Copper foams as having superior sound absorption coefficients.