Mechanics & Materials Research Group
The Mechanics and Materials Research Group’s underlying research focus is on increasingly sophisticated simulations and modelling frameworks, supported by complementary experimental testing, to assess and predict the performance of civil engineering structures and materials. This strong emphasis on modelling links several inter-related research themes which aim to consolidate and further enhance the group’s international research standing.
Multi-physics modelling
Multi-scale modelling
Novel Computational Modelling Techniques
Constitutive modelling and experimental testing
Biomechanics
Multi-physics modelling
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Research on multi-physics modelling moves beyond the traditional approach of isolating individual processes (mechanical, thermal, hygral, chemical). Constitutive models for complex material behaviour are brought together with modelling of the relevant coupled processes (mechanical, thermal, multi-phase fluid flow) and advanced computational techniques to provide robust solution procedures for full scale multi-physics problems. This is exemplified by the group's major contribution to the EU-funded MAECENAS project on the development of a coupled hygro-thermo-mechanical simulation framework to assess ageing effects in prestressed concrete nuclear reactor vessels, further supported by an EU Marie-Curie Fellowship and British Energy-funded experimental programme. Expertise in thermo-chemo-mechanical modelling of concrete degradation was instrumental in assessment of delayed ettringite formation and retrofit strategies for a major viaduct in Malaysia.
Group members are at the forefront of international efforts to develop improved understanding, constitutive modelling and numerical modelling of hydro-mechanical behaviour of unsaturated soils, with a wide range of applications, including impact of climate change on slope instabilities and compacted clay barriers for underground storage of nuclear waste. This research takes place within a Marie-Curie Research Training Network on Mechanics of Unsaturated Soils for Engineering (MUSE), funded by the EU for 4 years (2004-08), involving 6 European Universities and coordinated from Glasgow. The EPSRC-funded HYDRO-DDA project applied novel hydro-mechanical modelling to investigate the capacity of fractured mudrocks as seals to over-pressurised petroleum reservoirs.
Multi-scale modelling
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Research on multi-scale techniques and associated phenomena represents a new avenue of research for the group. Computational mechanics techniques (collaboration with Swansea and Strathclyde Universities in separate EPSRC-funded projects) provide realistic and robust macroscopic models that fully capture the influence of smaller scale processes and properties - materials include concrete, masonry, biological materials and fibre-reinforced composites. Augmented by research into the structural size effect and coupled with the multi-physics and computational modelling themes, different mechanical and environmental conditions as well as physical sizes (for which experiments are either impractical or impossible) can be addressed. Computational research on composites is continuing in collaboration with experimental research in Mechanical Engineering at Glasgow and Strathclyde.
Novel Computational Modelling Techniques
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The group has made significant advancement in the development and application of a whole range of novel computational modelling techniques. The group has an international reputation for its work on the Extended Finite Element Method (XFEM), with applications from fracturing to biofilms and tumour growth. Novel frameworks for modelling discontinuous media or emerging discontinua (Discrete Element Method, Rigid Body Spring Method, Numerical Manifold Method and Non Smooth Contact Dynamics) have been the subject of extensive research, with applications to safety critical discontinuous multi-body systems, such as integrity of nuclear reactor graphite core brick assemblies. Further research efforts include the Boundary Element Method, including non-linear or multi-region problems and wave propagation (earthquake waves or underground explosions).
Constitutive modelling & experimental testing
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The strong emphasis on computational mechanics is balanced by the group's work on constitutive modelling and experimental testing. Constitutive models for complex material behaviour are informed by appropriate experimental testing and form an integral part of multi-physics modelling. Geotechnical examples include hydro-mechanical behaviour of unsaturated soils, plastic anisotropy and bonding/destructuration effects in soft clays. The latter is linked to two Marie-Curie Research Training Networks: SCMEP and AMGISS. Research on constitutive modelling of concrete includes combining plasticity theory and damage mechanics to produce major improvements in simulations involving crack formation and growth. The computational-experimental link has been strengthened by a current Glasgow/Paisley Centre for Microstructural Modelling and Characterisation of Cementitious Materials, funded by EPSRC.
Biomechanics
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The group intends to broaden its research portfolio by embracing fully the expertise of its staff to include emerging research fields, in particular biomechanics e.g. constitutive modelling of soft tissue and mechano-stimulation of bone.
Recent advances in computational mechanics (including mathematical modelling of materials and numerical methods) can provide the tools necessary to make significant advances in the simulation and prediction of the human body under both normal and abnormal conditions. Computational mechanics allows us to develop a virtual laboratory whereby extremes of size and conditions can be studied is a real possibility.
Research underway includes the development of a computational model for the intervertebral disc (anisotropic hyperelastic constitutive model).