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SS1202

The project

Composite materials are being used in high-strain-rate dynamic environments, such as in wind turbines, more flexible aircraft and lighter engines. Unfortunately, current vibration models and testing procedures are not capable of capturing realistic behaviour of these new structures under operational conditions. In particular, vibration responses at resonances can exhibit unpredictable nonlinear dynamics so far not experienced with metallic materials.

Objectives:

The main objective of this research work is to develop a methodology for quantifying and identifying non-linear dynamic behaviour of aero-engine components/assemblies made of composites. Such a methodology will deliver the means for understanding the non-linear dynamics of these structures for the relatively high vibration levels encountered in service.

Dynamics of Composite Structures today:

Non-linear dynamic behaviour of structural components can be caused by several reasons. The principal one that is studied in this research project is due to the mechanical properties of the multilayer composite components under both pristine and damaged conditions.To date, the linear dynamics of composite structures can be correctly described with current modal analysis tools and so FE models of composites can be verified and validated within their linear boundaries. Beyond those, the modal properties of composites cannot be determined adequately. The fundamental unknown in the current FE models is the stress level at resonant condition because of the unpredictable distortion of the resonant response curve. In fact, both stiffness and damping are undetermined and so any forced response predictions of linear models cannot be correlated with the experimental counterpart. Without knowing the necessary physics for describing non-linear dynamic phenomena the model validation process cannot be started.

A Fundamental Understanding

The core of this PhD proposal focuses on the understanding of the physics for describing non-linear dynamic phenomena at high levels of strain rates of these materials. It is relevant to learn which thermo-mechanical parameters are critical in this physics, how to quantify these parameters so as to obtain coefficients to describe the dynamic behaviour of the nonlinear element(s). This PhD will involve a mixture of material modelling, FE analysis and experimental tests. There will be a healthy interaction with a relevant aero-engine industry.

Candidate requirements

Candidates will be expected to have a minimum of 2:1 honours degree (or equivalent) in Mechanical Engineering, Aerospace Engineering, Material Science, Physics, Mathematics or related subjects.  Candidates are also required to have a background in dynamics and basic knowledge of materials, such as carbon-fibre reinforced materials.

Funding

This 3 year studentship covers full UK/EU (EU applicants who have been resident in the UK for 3 years prior to application) PhD tuition fees and a tax-free stipend at the current RCUK rate (£13,726 in 2013/14).  EU nationals resident in the EU may also apply and will qualify only for PhD tuition fees.

For further information on eligibility criteria, please see: http://www.epsrc.ac.uk/skills/students/help/Pages/eligibility.aspx

How to apply

To apply for this studentship submit a PhD application using our online application system, via the ‘Apply’ button below.

Please ensure that in the Funding section you tick “I would like to be considered for a funding award from the Department” and specify the title of the scholarship in the “other” box below.

Contacts

For general application enquiries, please email gseng-pgrs@bristol.ac.uk. 

Deadline for applications

This studentship will remain open until filled.