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  Micromechanical approaches for predicting fragmentation and abrasion of brown rice


   Materials and Engineering Research Institute

  ,  Applications accepted all year round  Self-Funded PhD Students Only

About the Project

The Industry and Innovation Research Institute (I2Ri) draws on talents, expertise and facilities across Sheffield Hallam University. The vision is to be the leading provider of applied research excellence delivering materials, computing, science and engineering innovations meeting the development needs of industry.

PhD Research Topic

Rice milling is a high-bulk, high-value process. Worldwide, over 500 million tonnes of rice are milled annually. Milling induces frictional contacts between brown rice grains such that outer layers (bran) are removed through abrasion. Ideally, material removal is uniform and sufficient in depth, minimizing grain breakage and energy input. Improvements in rice milling have the potential to 1) Reduce waste and energy consumption, bringing benefits in food security and reduced land/freshwater requirements in cultivation; 2) Increase effective recovery and useability of byproducts; 3) Increase value and consistency in output.

Recent efforts to improve the design and operation of rice mills have employed multiparticle simulations using the Discrete Element Method (DEM) which involves tracking and computing the interactions of individual grains. However, mathematical models of rice abrasion and impact have, to date, achieved limited success in predicting bran removal degree and breakage probability, limiting simulation-based efforts at milling optimisation.

Aims

The main aims of the project are to:

  • Develop improved relations for predicting bran removal degree arising from grain abrasion as a function of normal contact force, drag path and abrasion history
  • Develop improved relations for predicting fragmentation of rice grains due to impact, as a function of contact velocity, contact angle and impact history
  • Develop improved understanding of the separation and fragmentation mechanisms involved in abrasion and attrition of rice grains and appropriate modelling methods to represent these
  • Relations developed will be applied in multi-particle simulations of rice milling. This will be achieved by numerical micromechanical modelling, in which the microstructure of rice grains will be represented, and mechanical testing.

Methodology

In this project, the successful candidate will, firstly, develop a small-scale mechanical model of a brown rice grain using Finite Element Analysis (FEA). This model will be used to analyse the mechanisms by which layer removal and grain breakage occur and determine predictive relationships based on systematic investigations into the effects of contact force/velocity/angle and impact/abrasion history. Secondly, the student will develop and use mechanical tests to validate the proposed separation/fragmentations mechanisms and the predictions of the FEA model; and inform further development of the FEA model.

The following tools and software will be available for the project:

  • Abaqus
  • STAR-CCM+
  • Full-scale vertical rice mill
  • Industry-standard texture analyser
  • Tribological testing equipment
  • Eifeler Image Analysis Suite
  • High-speed digital camera

By undertaking this project, the student will:

  • Gain expertise in key numerical, experimental and particle characterisation techniques widely used for soft granular materials in the food industry
  • Work with experts at the National Centre for Excellence in Food Engineering (NCEFE)
  • Use cutting-edge equipment and methods used in the food industry
  • Have the opportunity to undertake a placement with Koolmill Systems Ltd., a manufacture of next-generation rice mills
  • Receive formal training in DEM from a leading research group

The successful candidate will be expected to be able to demonstrate strong ability in experimental mechanics or relevant engineering simulation techniques, preferably both. Experience in designing and conducting mechanical tests will be highly beneficial, as will practical experience with relevant engineering software (FEA and/or DEM), though additional formal and informal software training can be provided. 

Eligibility

Applicants should hold a 1st or 2:1 Honours degree in a related discipline. A Master’s degree in a related area is desirable. We welcome applications from all candidates irrespective of age, pregnancy and maternity, disability, gender, gender identity, sexual orientation, race, religion or belief, or marital or civil partnership status.

International candidates are required to provide an IELTS certificate with a score of at least 6.5 overall, and a minimum of 6.0 in all components. For further information on English Language requirements, please click here.

For further details on entry requirements, please click here.

How to apply

All applications must be submitted using the online application form. To apply, click here. In your application, be sure to include the title of the project that you are applying for.

As part of your application, please upload:

  • A research proposal (max. 1500 words) in your own words, briefly outlining the proposed research, the current knowledge and context referencing key background literature; a proposed methodology or approach to answer the key questions, and any potential significance or impact of the research
  • Copy of your highest degree certificate
  • Non-UK applicants must submit IELTs results (or equivalent) taken in the last two years and a copy of their passport.

Applicants must provide 2 references, with at least one to be academic. References must be received directly from the referees.

We strongly recommend you contact the lead academic, Ben Edmans , to discuss your application.

For information on how to apply please visit https://www.shu.ac.uk/research/degrees

Engineering (12) Materials Science (24)

Funding Notes

There is no funding attached to this project. The applicant will need to fund their own tuition fees, as well as any associated bench fee and living expenses. The home tuition fee for 24/25 is £4,786 and the international tuition fee for 24/25 is £17,205 (not including any applicable bench fee). For further information on fees, visit View Website.

For information regarding bench fees, please contact


References

[1] Cao, B., Jia, F., Zeng, Y., et al. (2018). Powder Technology 325, 429-440.
[2] Han, Y., Jia, F., Zeng, Y., et al. (2016). Powder Technology 297, 153-164.
[3] Zeng, Y., Mao, B., Jia, F., et al. (2022). Biosystems Engineering 215, 32-48.
[4] Zabidin, Z., Omar, F. N. & Hafid, H. S. (2018). Biosystems Engineering, 176, 48-58.

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