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Correlation of mechanical properties to rain erosion resistance of polymeric materials

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dc.contributor.advisor Young, Trevor M.
dc.contributor.advisor Tobin, Edmond F. O'Carroll, Anthony 2019-02-18T16:09:53Z 2019-02-18T16:09:53Z 2018
dc.description peer-reviewed en_US
dc.description.abstract Rain erosion of leading edges of wind turbine blades is caused by repeated high speed liquid droplet impacts, which provokes damage in the form of pitting or peeling over time and can lead to a signi cant reduction in performance if left untreated. Currently, polymeric coatings are applied to the surface of the wind turbine during manufacture in order to mitigate the issue; however, it has been reported that these coatings are being eroded within the first 25 years of the 15-25 year life cycle of the blades. The focus of this study is to assess which material properties have an impact on the erosion resistance. A range of polymeric materials, including polycarbonate, polyethylene, polyethylene terephthalate, poly(methyl methacrylate) and polypropylene, were first tested in the Whirling Arm Rain Erosion Rig (WARER) to assess their ability to resist rain erosion. Nano- and macro- scale mechanical testing alongside ultrasonic testing were used to assess their mechanical properties (including storage and loss moduli, hardness and elastic, viscoelastic, and acoustical characteristics) and topographic parameters. The results indicated a number of correlations. A reduction in both stiffness and hardness, and the ability to damp out impact energy and recover to their original shape very quickly is important for rain erosion resistance. It was shown that a reduction in the acoustical impedance of the material is strongly connected to good erosion resistance. Using a Nanoindenter G200, an analytical model of the viscoelastic response of the materials was developed, which showed that strong elastic components are important for rain erosion resistance. Scanning probe microscopy carried out at various stages of the erosion process showed that the roughness of the polymeric materials increases with time up to a critical roughness (SaCRIT), before which no significant mass loss will occur { this indicates that tougher materials can withstand roughening for longer. Furthermore, it was found that the rate at which a polymer is roughened during the incubation period is related to the rate at which it loses mass in the mass loss period, providing an empirical insight into the mechanics of the rain erosion of these materials. en_US
dc.language.iso eng en_US
dc.subject rain erosion en_US
dc.subject liquid impact erosion en_US
dc.subject polymers en_US
dc.subject nanoindentation en_US
dc.subject erosion testing en_US
dc.subject ultrasonic en_US
dc.subject surfce anlaysis en_US
dc.title Correlation of mechanical properties to rain erosion resistance of polymeric materials en_US
dc.type info:eu-repo/semantics/masterThesis en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.contributor.sponsor School of Engineering, UL en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US

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