scholarly journals Size Effects in Finite Element Modelling of 3D Printed Bone Scaffolds Using Hydroxyapatite PEOT/PBT Composites

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1746
Author(s):  
Iñigo Calderon-Uriszar-Aldaca ◽  
Sergio Perez ◽  
Ravi Sinha ◽  
Maria Camara-Torres ◽  
Sara Villanueva ◽  
...  

Additive manufacturing (AM) of scaffolds enables the fabrication of customized patient-specific implants for tissue regeneration. Scaffold customization does not involve only the macroscale shape of the final implant, but also their microscopic pore geometry and material properties, which are dependent on optimizable topology. A good match between the experimental data of AM scaffolds and the models is obtained when there is just a few millimetres at least in one direction. Here, we describe a methodology to perform finite element modelling on AM scaffolds for bone tissue regeneration with clinically relevant dimensions (i.e., volume > 1 cm3). The simulation used an equivalent cubic eight node finite elements mesh, and the materials properties were derived both empirically and numerically, from bulk material direct testing and simulated tests on scaffolds. The experimental validation was performed using poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers and 45 wt% nano hydroxyapatite fillers composites. By applying this methodology on three separate scaffold architectures with volumes larger than 1 cm3, the simulations overestimated the scaffold performance, resulting in 150–290% stiffer than average values obtained in the validation tests. The results mismatch highlighted the relevance of the lack of printing accuracy that is characteristic of the additive manufacturing process. Accordingly, a sensitivity analysis was performed on nine detected uncertainty sources, studying their influence. After the definition of acceptable execution tolerances and reliability levels, a design factor was defined to calibrate the methodology under expectable and conservative scenarios.

2010 ◽  
Vol 70 ◽  
pp. 167-172 ◽  
Author(s):  
Dietmar Gruber ◽  
Harald Harmuth

Simulations presented here aim to show reasons for undesirable product heterogeneity and possible defects. Potential negative influences are for example insufficient deaeration, friction between the bulk material and the mould, deformation of the mould and an inappropriate mould filling. In a first step data were collected from a production process. This includes the load and displacement during moulding and the mass of the mix filled into the mould. For the Finite Element modelling with ABAQUS the brick material was simulated with a Drucker-Prager model including a cap. The results show the influence of the friction between mix and mould on the densities and stresses in the pressed blank.


Procedia CIRP ◽  
2016 ◽  
Vol 55 ◽  
pp. 109-114 ◽  
Author(s):  
Filippo Montevecchi ◽  
Giuseppe Venturini ◽  
Antonio Scippa ◽  
Gianni Campatelli

2018 ◽  
Vol 79 ◽  
pp. 135-146 ◽  
Author(s):  
Alessandro Caimi ◽  
Francesco Sturla ◽  
Francesca Romana Pluchinotta ◽  
Luca Giugno ◽  
Francesco Secchi ◽  
...  

2019 ◽  
Vol 15 ◽  
pp. 28-32
Author(s):  
Ran He ◽  
Liguo Zhao ◽  
Vadim V. Silberschmidt ◽  
Yang Liu ◽  
Felix Vogt

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