Investigating the post-yield behavior of mineralized bone fibril arrays using a 3D non-linear finite element unit-cell model.

In this study, we propose a 3D non-linear finite element (FE) unit-cell model to investigate the post-yield behavior of mineralized collagen fibril arrays (FAY). We then compare the predictions of the model with recent micro-tensile and micropillar compression tests in both axial and transverse directions. The unit cell consists of mineralized collagen fibrils (MCFs) embedded in an extrafibrillar matrix (EFM), and the FE mesh is equipped with cohesive interactions and a custom plasticity model. The simulation results confirm that MCF plays a dominant role in load bearing prior to yielding under axial tensile loading. Damage was initiated via debonding in shear and progressive sliding at the MCF/EFM interface, and resulted in MCF pull-out until brittle failure. In transverse tensile loading, EFM carried most of the load in pre-yield deformation, and then mixed normal/shear debonding between MCF and EFM began to form, which eventually produced brittle delamination of the two phases. The loading/unloading FE analysis in compression along both axial and transverse directions demonstrated perfect plasticity without any reduction in elastic modulus, i.e., damage due to the interfaces as seen in micropillar compression. Beyond the brittle and ductile nature of the stress-strain curves, in tensile and compressive loading, the simulated post-yield behavior and failure mechanism are in good quantitative agreement with the experimental observations. Our rather simple but efficient unit-cell FE model can reproduce qualitatively and quantitatively the mechanical behavior of bone ECM under tensile and compressive loading along the two main orientations. The model's integration into higher length scales may be useful in describing the macroscopic post-yield and failure behavior of trabecular and cortical bone in greater detail

Influence of micro-scale uncertainties on the reliability of fibre-matrix composites

Acknowledgements This work was supported by the University of Aberdeen Elphinstone scholarship scheme.Peer reviewedPostprin

Thermal–mechanical metamaterial analysis and optimization using an Abaqus plugin

Open Access via the Springer AgreementPeer reviewe

Development of a Multi-scale Surrogate-based Tool for Composite Property Estimation

Peer reviewedPublisher PD

Multi-scale Reliability-Based Design Optimisation Framework for Fibre-Reinforced Composite Laminates

Acknowledgements This work was supported by the University of Aberdeen Elphinstone scholarship scheme.Peer reviewedPostprin

Multiscale surrogate-based framework for reliability analysis of unidirectional FRP composites

This work was supported by the University of Aberdeen Elphinstone scholarship scheme.Peer reviewedPostprin

Development of an ABAQUS Plugin Tool for Periodic RVE Homogenisation

Open Access through Springer Compact Agreement.Peer reviewedPublisher PD

Novel multi-zone self-heated composites tool for out-of-autoclave aerospace components manufacturing

In this paper, a multi-zone self-heating composite tool is developed to manufacture out-of-autoclave complex and high-quality business jet lower wing stiffened composite panel. Autoclave manufacturing is regarded as a benchmark for manufacturing aerospace-grade composite parts. However, high accruing operational costs limit production rates thereby not being practical for smaller-scale companies. Therefore, significant work towards developing out-of-autoclave manufacturing is underway. In this study, a production line tool is developed with embedded heating fabric that controls temperature at the desired zones, replacing the need for autoclave cure. It investigates and identifies the optimal design parameters of the self-heating setup namely the placement of the heating fabric, zones, thermal management system, temperature distribution, heating rate and thermal performance using a thermal FEA model. The associated thermal characterisation of the tooling material and the part are measured for accurate simulation results. The design developed in this study will be used as production guideline for the actual tool