Background:

Christopher is a Senior Lecturer of Solid Mechanics in the Department of Aeronautical and Automotive Engineering. He studied his MEng degree in Aeronautical Engineering at Loughborough University, graduating in 2009. From 2006 to 2008, during his MEng studies, he worked as a Technical Analysis Engineer at Pall Aerospace Limited. Christopher received his PhD on the mechanics of interface fracture from Loughborough University in 2012. He then joined the Department of Aeronautical and Automotive Engineering at Loughborough University as a Lecturer of Solid Mechanics and was promoted to Senior Lecturer in 2017.

Qualifications:

• PhD on the mechanics of interface fracture, titled “Mixed-Mode Partition Theories for One-Dimensional Fracture” (2012), Loughborough University
• MEng degree in Aeronautical Engineering (2009), Loughborough University
• Fellow of the Higher Education Authority FHEA 2015

Key Awards:

• School of AACME Teaching Awards, Academic years 2021–22, 2017–18, 2015–16, 2013–14
• University award for PhD rapid completion (less than three years)
• Airbus Science, Engineering and Technology Award (2009)

Outline of main research interests:

• Christopher’s research focuses on analytical mechanical modelling, and numerical simulation to solve and develop key challenges in solid mechanics. He has over 40 publications, including at prestigious outlets, e.g., Nature Communications. He has supervised five PhD students to completion. His recent projects include: 
• Interface fractures in layered materials, considering the mechanics of mixed-mode fracture, fracture toughness assessment, and prediction of fracture initiation and propagation. Methods include analytical and theoretical mechanical development, numerical simulation using the finite-element method (FEM), and experiment by various fracture tests. Applications include delamination of fibre-reinforced laminates; blistering and spallation of protective coatings, oxides, and thin films; adhesion toughness of graphene membranes.
• Spallation and lifetime assessment of thermal barrier coatings (TBCs), sponsored by Rolls-Royce, developing the mechanical theory of TBC spallation, and validated against thermal-cycling tests of turbine blades.
• High-velocity ballistic impact of body armour, sponsored by Permali, using LS-DYNA to conduct hybrid FEM/smoothed-particle hydrodynamics (SPH) simulations of body armour resistance against small-arms fire, and validated against SHPB and ballistic impact tests. Aims to engineer material systems and interfaces to deliver enhanced performance.
• Theory of dynamic fracture, in collaboration with the Chinese Academy of Sciences (CAS), considering the role of vibration in driving fracture in structures under high rates of loading. Methods include analytical and theoretical mechanical development, numerical simulation with the FEM, and experiment by dynamic fracture tests.
• Physics-informed models for source-term estimation (STE) of airborne emissions such as greenhouse gases (GHGs), funded by NERC. Methods include development of numerical simulation codes for dispersion, and Bayesian inference using Kalman filters. Validated against UAV-based mobile sensor measurements.
• Partition of Mixed-Mode Fractures by Digital Image Correlation (DIC), funded by EPSRC (EP/M000958/1).

Grants and contracts:

• 2023 – Methane STEALS (Methane Source Term Estimation At Landfill Sites), funded by NERC
• 2014 – 2015 – Partition of Mixed-Mode Fractures by Digital Image Correlation (DIC), funded by EPSRC (EP/M000958/1)

Current teaching responsibilities:

• TTP402 Body Engineering (postgraduate)
• TTC012 Spacecraft Engineering (third-year undergraduate)
• TTC002 Finite-Element Methods (third-year undergraduate)
• TTA003 Thermofluids (first-year undergraduate)

Current administrative responsibilities:

• Director of Undergraduate Studies for the School of AACME (Aeronautical, Automotive, Chemical and Materials Engineering) since 2022
• Member of the Departmental Teaching and Learning Committee
• Programme Director of the Aeronautical Engineering undergraduate courses from 2016 to 2022

Selected publications:

1. “Adhesion toughness of multilayer graphene films”, Nature Communications (2017): Interface adhesion toughness between multilayer graphene films and substrates is a major concern for their integration into functional devices. It has been widely reported that the standard test to measure adhesion toughness (the blister test) displays seemingly anomalous behaviour, in which the adhesion toughness depends on the number of graphene layers. This work discovers the reason for this behaviour; shows how to correctly calculate the adhesion toughness and does so for graphene films on silicon substrates; corrects a key misunderstanding in the literature; and presents a general methodology.
2. “Dynamic Crack Propagation along Elastic Interfaces in Double Cantilever Beams under High Loading Rates”, Journal of Aerospace Engineering (2022): Under high rates of loading, structural vibration can have a significant effect on the driving force for fracture (“energy release rate” or ERR). In this work, the dynamic ERR of cracks propagating under high loading rates is derived analytically for the first time and validated two experimental cases, demonstrating the excellent ability of the developed theory in capturing the crack propagation behaviour as well as assessing dynamic ERR.
3. “A new spallation mechanism of thermal barrier coatings and a generalized mechanical model”, Composite Structures (2019): In this work we discover a new failure mode of thermal barrier coatings (TBCs) in aero engines and derive and validate a generalized model for TBC spallation.
4. “Spontaneous formation and morphology of telephone cord blisters in thin films: The Ω formulae”, Composite Structures (2019): In this work, we discover the formation mechanism of telephone cord blisters (TCBs) in thin films and derive formulae for their morphologies for the first time since TCBs were observed in the 1960s. As well as representing the state-of-the-art in fracture mechanics of thin films, this work is significant for the lifetime assessment of thermal barrier coatings (TBCs) in aero engines.
5. “Spallation of thin films driven by pockets of energy concentration”, Theoretical and Applied Fracture Mechanics (2016): This work explains the spallation mechanics of thin coatings and discovers a new failure mechanism. It develops a theoretical model based on continuum mechanics, fracture mechanics, and the work's new understanding. The model gives excellent agreement with independently obtained experimental measurements. It can explain and predict the nucleation, blistering and spallation behaviour of thin coatings. The work has opened a new avenue for research, particularly in the failure of thermal barrier coatings (TBCs) on turbine blades.
6. “Partition of mixed-mode fractures in 2D elastic orthotropic laminated beams under general loading”, Composite Structures (2016): This work presents a general theory for interface fracture between dissimilar materials, which is one key consideration in structural design. Before this work, the problem could only be solved using time-consuming numerical simulation with high mesh densities, or by incorrectly ignoring the material mismatch. A completely analytical closed-form theory is presented. It is mathematically elegant and provides understanding of the underlying physics. The work has recently been applied to the study of spallation of thermal barrier coatings in gas turbine engines, graphene adhesion, telephone cord blisters in thin films, film blistering of gold coatings, etc.
7. “Experimental assessment of mixed-mode partition theories for generally laminated composite beams”, Composite Structures (2015): This work answers the question, what is the most appropriate way to assess the delamination toughness of generally laminated fibre-reinforced polymer (FRP) composite materials under mixed-mode loading. It examines the performance of various mixed-mode partition theories in the literature at predicting the delamination toughness of laminates tested under mixed-mode loading. It discovers that the authors’ partition theory provides the best prediction and closely agrees with an independently obtained empirical partition theory, constructed with the aid of experimental measurements.

 View central publications database

External Collaborators: 

• Rolls-Royce, Derby
• Permali
• Chinese Academy of Sciences

External roles and appointments:

• Plenary, invited, or keynote lectures
• Plenary keynote lectures at the 4th and 5th International Conferences on Advanced Materials and Engineering Applications (Handan, China, 2021, 2022).
• Plenary lecture at the 1st International Conference on Theoretical, Applied, and Experimental Mechanics (Paphos 2018).
• Plenary lecture at the Chinese-Franco Symposium on Damage and Fracture of Composite Structures (Peking University 2017).
• Plenary lecture at the 14th International Conference on Fracture (Rhodes 2017).
• Plenary lecture at the 1st World Conference on Fracture and Damage Mechanics at Mahatma Gandhi University (Kottayam, Kerala, India, 2014).
• Invited lecture at a meeting of Technical Committee 4 of the European Structural Integrity Society (Switzerland 2012).
• Plenary lecture at the 16th International Conference on Composite Structures (Porto 2011).

Conference session chair or organiser:

• Joint organiser and chair of a mini symposium at the 14th International Conference on Fracture (Rhodes 2017).
• Joint organiser and chair of a session at the 21st International Conference on Composite Materials (Xi’an 2017).
• Session chair at the 24th, 20th,19th, 18th and 17th International Conference on Composite Structures (Porto 2021, Paris 2017, Porto 2016, Lisbon 2015, Porto 2013).
• Session chair at the 2nd International Conference on Mechanics of Composites (Porto 2016)

External appointments:

• Adjunct professor of Mechanical Engineering at School of Machinery and Equipment Engineering, Hebei University of Engineering, Handan, China.

Societies:

• Technical Committee 4 of the European Structural Integrity Society (2012–2018), including participation in the international “numerical round-robin” on mixed-mode fracture during 2012–2013.