Stress concentration and strain hardening in structural steel

Volosevich, P. Yu.; Shiyan, A. V.

doi:10.3103/s0967091215060145

Cited by 5 publications

(1 citation statement)

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“…Porous structures inevitably contain features that cause the stress to concentrate and hence initiate plastic deformation. The resulting strain hardening of the deforming region locally increases the yield strength in that region [224][225][226]. However, the material continues to fail as the strain hardening cannot raise the yield strength at a rate greater than the increase in stress due to the reduced area of the deformation.…”

Section: Discussionmentioning

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: Discussionmentioning

confidence: 99%