Nathan Klavzer
PhD student
Master in chemical and materials engineering at UCLouvain in 2019

Main project: Micro- and nano- mechanical characterisation and modelling of composites at the local fibre/matrix level
Funding: UCL Project Viscos
Supervisor(s): Thomas Pardoen

The use of fibre reinforced polymer composites in lightweight structural applications requires the accurate prediction of their deformation and failure mechanisms. Increasing the predictive capabilities of current computational models (mostly phenomenological) implies moving towards multi-scale micromechanics-based approaches. One of the main current bottlenecks in the field is the absence of a sufficiently quantitative micro-scale description of the mechanical behaviour of the matrix, interface and interphase with the fibres. This involves characterising and modelling the origin of the difference of behaviour between the matrix when confined in small volumes between fibres, and the bulk. The development of a proper description of the behaviour of the matrix/fibre interphase and interface regions is another important challenge as they affect the load transfer and failure mechanisms. A key aspect is a proper treatment of the local viscoplastic, back-stress and anisotropy effects within the constitutive framework. The aim of the PhD thesis is to tackle these questions using a combined experimental and numerical approach with application to a thermoset, a thermoplastic and a bio-sourced matrix. Nano/micro-mechanical measurements such as nanoindentation, atomic force microscopy and in-situ testing within a scanning electron microscope relying on micro-digital image correlation, will be conducted to evaluate the matrix and interphase responses as a function of strain rate and degrees of cure. Push-out tests will be used to characterise the interface behaviour. The outcome of these tests will be used to enrich molecular-informed micro/meso-mechanical models. The success of the research project will be measured, at the fundamental level, by the capacity to unravel the size and molecular-structure dependent deformation nano/micro-mechanisms, and, at a more applied level, by the ability to model the macroscopic response of UD composites based on the constituent properties.

IMMC main research direction(s):
Processing and characterisation of materials
Solid mechanics

finite elements
multi-scale modeling

Research group(s): IMAP

Recent publications

See complete list of publications

Journal Articles

1. Pardoen, Thomas; Klavzer, Nathan; Gayot, Sarah; Van Loock, Frederik; Chevalier, Jérémy; Morelle, Xavier; Destoop, Vincent; Lani, Frédéric; Camanho, Pedro; Brassart, Laurence; Nysten, Bernard; Bailly, Christian. Nanomechanics serving polymer-based composite research. In: Comptes Rendus. Physique, Vol. 22, no. S3, p. 1-22 (2021). doi:10.5802/crphys.56.

Conference Papers

1. Klavzer, Nathan; Van Loock, Frederik; Chevalier, Jérémy; Brassart, Laurence; Pardoen, Thomas. Visco-Plastic Behaviour of a Polymer Matrix at the Fibre Diameter Length Scale: a Finite Element Mesoscale Model Relying on Shear Transformation Zone (STZ) Dynamics. 2021 xxx.

2. Pardoen, Thomas; Morelle, Xavier; Chevalier, Jérémy; Klavzer, Nathan; Van Loock, Frederik; Lani, Frédéric; Brassart, Laurence; Camanho, P.; Bailly, Christian. Towards more predictive composite models. 2019 xxx.