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Clamping Force Relaxation-Based Bolted joint Design to Prevent Failure (RDF23/MCE/JALALI)

   Faculty of Engineering and Environment

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  Dr Hassan Jalali, Dr Hamed Farokhi  No more applications being accepted  Competition Funded PhD Project (Students Worldwide)

About the Project

Bolted joints are widely used in a variety of engineering applications, from aerospace to automotive and transport to energy industries. They are commonly subject to dynamical loads in a wide frequency range causing vibration into the connected substructures. Furthermore, when under dynamic loading, bolted joints could get loose due to a loss in the clamping pressure in the joints, known as relaxation [1]. If left undetected, this vibrational loosening could cause serious problems, and in some cases even lead to fatal consequences. One area in which bolt loosening could be disastrous is train derailment. Some examples of train derailment due to bolt loosening are: 

  • 2002 London (Potters Bar) WAGN train derailment, 7 deaths, 2 critically injured, Suspected cause: loose bolts [2] 
  • 2007 Grayrigg (Cumbria) WCR train derailment, 1 fatally injured, 28 seriously injured, Suspected cause: loose bolts [3]
  • 2013 Paris SNCF train derailment, 7 deaths, dozens of injuries, Suspected cause: loose fishplate bolts [4] 

Additionally, bolt loosening can cause economic and environmental problems as well. Rail lines remain closed for months for rail replacement and maintenance after a train derailment. Bolt loosening could have also environmental effects, for example in the case of a freight train derailment (e.g., fire and fuel splash to the environment in NRW train derailment near Swansea, 2020). The main question is why aren't bolted joints being designed in a way to prevents bolt loosening? The state-of-the-art practices for bolted joints design are based on static and fatigue requirements. More specifically, they are designed to withstand specific level of static or dynamic loads, dependent on the application they are used for. The conditions triggering loosening, on the other hand, are activated after installation which are not taken into account in the design stage. Although a few techniques are used to reduce loosening after installation, they are not always effective. Another approach used to overcome loosening in rail tracks is continuous welded rail (CWR). This approach is a permanent joint strategy and does not offer the advantages of bolted joint connections.  

This project aims to propose a novel approach for designing bolted joints in which loosening (relaxation) dynamics and the conditions triggering it are accounted for as dominant factors. This demands a deep understanding of the bolt loosening phenomenon as well as a sophisticated model formulating its inherent dynamics. Numerical simulations and experimental investigations will be carried out to verify the accuracy of the developed strategy. The results of this project could create a step-change in the design of bolted joints for railway applications and could benefit rail companies in the enhancement of the reliability of the rail lines as well as saving human lives and the environment.  

The successful applicant will have knowledge of theoretical and numerical modelling in dynamics and vibration and experience in finite element modelling of structures. Good written and oral communication skills are essential.

Academic Enquiries

This project is supervised by Dr Hassan Jalili. For informal queries, please contact [Email Address Removed]. For all other enquiries relating to eligibility or application process please use the email form below to contact Admissions. 

Funding Information

Home and International students (inc. EU) are welcome to apply. The studentship is available to Home and International (including EU) students and includes a full stipend at UKRI rates (for 2022/23 full-time study this is £17,668 per year) and full tuition fees. Studentships are also available for applicants who wish to study on a part-time basis over 5 years (0.6 FTE, stipend £10,600 per year and full tuition fees) in combination with work or personal responsibilities). 

Please also see further advice below of additional costs that may apply to international applicants.

Eligibility Requirements:

  • Academic excellence of the proposed student i.e. 2:1 (or equivalent GPA from non-UK universities [preference for 1st class honours]); or a Masters (preference for Merit or above); or APEL evidence of substantial practitioner achievement.
  • Appropriate IELTS score, if required.
  • Applicants cannot apply for this funding if they are already a PhD holder or if currently engaged in Doctoral study at Northumbria or elsewhere.

Please note: to be classed as a Home student, candidates must meet the following criteria:

  • Be a UK National (meeting residency requirements), or
  • have settled status, or
  • have pre-settled status (meeting residency requirements), or
  • have indefinite leave to remain or enter.

If a candidate does not meet the criteria above, they would be classed as an International student. Applicants will need to be in the UK and fully enrolled before stipend payments can commence, and be aware of the following additional costs that may be incurred, as these are not covered by the studentship.

  • Immigration Health Surcharge
  • If you need to apply for a Student Visa to enter the UK, please refer to the information on It is important that you read this information very carefully as it is your responsibility to ensure that you hold the correct funds required for your visa application otherwise your visa may be refused.
  • Check what COVID-19 tests you need to take and the quarantine rules for travel to England
  • Costs associated with English Language requirements which may be required for students not having completed a first degree in English, will not be borne by the university. Please see individual adverts for further details of the English Language requirements for the university you are applying to.

How to Apply

For further details of how to apply, entry requirements and the application form, see  

For applications to be considered for interview, please include a research proposal of approximately 1,000 words and the advert reference (e.g. RDF23/…).

Deadline for applications: 27 January 2023

Start date of course: 1 October 2023 tbc


[1] Gong H, Liu J H, Feng H H. Review on anti-loosening methods for threaded fasteners. Chin J Aeronaut 35(2): 47–61 (2022)
[5] Jalali, Jamia, Friswell, Khodaparast, Taghipour, Mech Syst Signal Process., 179 (2022) 109339.
[6] Jamia, Jalali, Taghipour, Friswell, Khodaparast, Mech Syst Signal Process. 153 (2021) 107507.
[7] Jalali, Khodaparast, Madinei, Friswell, Mech Syst Signal Process. 129 (2019) 645-658.
[8] Jalali, Khodaparast, Friswell, J Sound Vib. 447 (2019) 186-204.
[9] Jalali, Mech Syst Signal Process. 66-67 (2016) 111–119.
[10] Jalali, Ahmadian, Int. J. Mech. Sci. 65 (2012) 75-82.

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