Supervisors: Lukasz Figiel, Mohad Mousavi-Nezhad

Summary:

When exposed to pressurized gaseous environments, composite materials can exhibit microscale damage phenomena such as micro-cavitation. Understanding of those damage phenomena in the presence of tiny gas molecules such as H2 is critical for future applications of composites for H2 storage. Here, we aim to develop a new chemo-mechanical phase field model that will predict onset and propagation of microscale damage as a function of material composition, hydrogen concentration/pressure, and loading conditions. The model will be experimentally informed (model parameters, microstructure) using a Bayesian approach.

Background

When exposed to pressurized gaseous environments, polymer composites can exhibit microscale damage phenomena including cavitation that can subsequently lead to catastrophic component failure. This is particularly important for future hydrogen storage applications, given the need for pressurizing gaseous hydrogen to satisfy certain volumetric constraints. These microscale damage phenomena are poorly understood in the presence of tiny gas molecules such as H2. Here we will exploit the concept of polymer composites reinforced with 2D nanoparticles (NPs) as means for controlling H2 transport and improving microdamage tolerance. Experimental investigation of the above phenomena is challenging as it requires understanding of a complex relationship between nano-structural features of the composite (e.g. NP aspect ratio), H2 transport, and H2-induced damage initiation/evolution across multiple length scales.

Aim

Here, we aim to develop a new chemo-mechanical phase field model that will enable predictions of hydrogen gas transport and microscale damage onset and propagation as a function of material composition, hydrogen concentration/pressure, and loading conditions. In turn, this will help to optimize material for a given hydrogen and loading environment. The model will be experimentally informed (e.g. microscopy, mechanical behaviour) using the Bayesian paradigm. An experimentally parametrized chemo-mechanical phase field model will be subsequently implemented within a finite-element framework to enable predictions of hydrogen-induced initiation and evolution of micro-damage processes as a function of material composition, hydrogen pressure, and temperature.

Outcome

• Enhanced understanding of the interactions between pressurized gaseous hydrogen on polymer composites.
• New chemo-mechanics phase-field approach to study microscale damage processes in polymer composites exposed to gaseous hydrogen environment.
• A statistical inference methodology exploiting Bayesian paradigm to determine model parameters from experiments (microstructural, material model).
• Experimentally-informed computational platform connecting an open-source finite element code with a Python-based statistical inference tool.

Links to HetSys Training

This project will develop an experimentally informed phase-field modelling methodology that captures an interplay between hydrogen transport and mechanical damage in composites. The HetSys training program will equip the student with various materials modelling approaches and computer programming skills required for the mathematical formulation and numerical implementation. It will also assist with the development of the Bayesian methodology to identifying model parameters and their uncertainties from experiments.

This project aims to develop a chemo-mechanics continuum modelling framework feeding from advanced material characterization techniques. HetSys is uniquely positioned to train a strong PhD student in continuum modelling techniques (PX912), and the Bayesian framework (PX914) to assist in the identification of model parameters from experiments.

Uncertainty quantification (UQ) of the experimental results will be key to pass it reliably onto the continuum model. Various concepts of the Bayesian framework will be investigated in that context to provide a fully predictive continuum model. HetSys training in UQ (PX914) will be key to this project.

Robust software development will be needed here: (1) to incorporate a chemo- mechanics phase-field concept within a finite element method-based open-source solver; and (2) to implement a statistical inference approach to link results of experimental work with the continuum model using Bayesian paradigm.

Are you interested in applying for this project? Head over to our Study with Us page for information on the application process, and the HetSys training programme.

For the 2023/24 academic year, UK Research and Innovation (UKRI) funding is open to both UK and International research students. Awards pay a stipend to cover maintenance as well as paying the university fees and providing a research training support grant. For further details, please visit the HetSys Funding Page

At the University of Warwick, we strongly value equity, diversity and inclusion, and HetSys will provide a healthy working environment dedicated to outstanding scientific guidance, mentorship and personal development. Read more about life in the HetSys CDT here.

HetSys is proud to be a part of the Physics Department which holds an Athena SWAN Silver award, a national initiative to promote gender equality for all staff and students. The Physics Department is also a Juno Champion, which is an award from the Institute of Physics to recognise our efforts to address the under-representation of women in university physics and to encourage better practice for both women and men.