Abstract

The innovative design of orthopedic implants could play an important role in the development of life-lasting implants, by improving both primary and secondary implant fixations. The concept of meta-biomaterials aims to achieve a unique combination of mechanical, mass transport, and biological properties through optimized topological design of additively manufactured (AM) porous biomaterials. In this study, we primarily focused on a specific class of meta-biomaterials, namely auxetic meta-biomaterials. Their extraordinary behavior of lateral expansion in response to axial tension could potentially improve implant-bone contact in certain orthopedic applications. In this work, a multitude of auxetic meta-biomaterials were rationally designed and printed from Ti–6Al–4V using a commercially available laser powder bed fusion process called selective laser melting. The re-entrant hexagonal honeycomb unit cell was used as a starting point, which was then parametrically tuned to obtain a variety of mechanical and morphological properties. In this two-step study, the morphology and quasi-static properties of the developed meta-biomaterials were assessed using mechanical experiments accompanied with full-field strain measurements using digital image correlation. In addition, all our designs were computationally modelled using the finite element method. Our results showed the limits of the AM processes for the production of auxetic meta-biomaterials in terms of which values of the design parameters (e.g., re-entrant angle, relative density, and aspect ratio) could be successfully manufactured. We also found that the AM process itself imparts significant influence on the morphological and mechanical properties of the resulting auxetic meta-biomaterials. This further highlights the importance of experimental studies to determine the actual mechanical properties of such metamaterials. The elastic modulus and strength of many of our designs fell within the range of those reported for both trabecular and cortical bone. Unprecedented properties like these could be used to simultaneously address the different challenges faced in the mechanical design of orthopedic implants.

Highlights

  • With the elderly population growing and the prevalence of osteoarthritis rising, the need to develop life-lasting implants is greater than ever [1,2,3]

  • ‘In this work, we characterized the mechanical properties of additively manufactured (AM), Ti-6Al-4V auxetic lattices that were based on the re-entrant hexagonal honeycomb unit cell and were fabricated using a commercially available laser powder bed fusion (L-PBF) process called selective laser melting (SLM) [16, 17]

  • Author’s response The unconnected struts in the obtained computer-aided design (CAD) file were deleted before the .STL files were send to the printer, using a different software. Doing this inside the ABAQUS environment would take a lot of time, which is why we decided to go through with a rectangular sample using the same unit cell size

Read more

Summary

INTRODUCTION

With the elderly population growing and the prevalence of osteoarthritis rising, the need to develop life-lasting implants is greater than ever [1,2,3]. We characterized the mechanical properties of AM, Ti-6Al-4V auxetic lattices that were based on the re-entrant hexagonal honeycomb unit cell and were fabricated using a commercially available laser powder bed fusion (L-PBF) process called selective laser melting (SLM)[16, 17]. This AM process uses a high-power laser beam to selectively fuse metal powder particles to build a part straight from a computer-aided design (CAD) file. This comprehensive library of mechanical and morphological properties provides currently lacking experimental data, to take further steps in the adoption of auxetic lattices within the field of orthopedics

MATERIALS AND METHODS
RESULTS
DISCUSSION
Design
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call