Advanced non-destructive testing of blade manufacturing defects

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2023
Thesis identifier
  • T16548
Person Identifier (Local)
  • 201851069
Qualification Level
Qualification Name
Department, School or Faculty
  • In response to the international climate crisis, governments across the globe have set target dates by which they aim to achieve net zero greenhouse gas emissions. These targets range between the years 2040 to 2060 depending on a range of environmental, technological, and political factors at play in each nation. The necessity to de-carbonise the electricity supply is key to this and due to its cost effectiveness, and technological maturity, wind power plays a major role. The size of installed wind capacity will continue to grow exponentially over the coming years thus making the manufacture of wind turbine blades a rapidly growing and developing sector [1].Non-destructive testing (NDT) is used across a wide range of engineering fields to ensure a final component is defect-free and can be guaranteed to perform as certified in each application. In the framework of blade manufacture, NDT is often in the form of ultrasonic inspections that can identify faults and errors in the early production phase so to prevent failures and reduce the cost of operations and maintenance. This thesis reports on research carried out to develop future ultrasonic NDT techniques applied to composite turbine blades. To that end, three innovative developments to improve the manufacturing environment, resulting in significant overall benefits for clean energy production, are presented. An in-process ultrasonic inspection system, using dry-coupled phased array inspection has been designed and tested for the inspection of Carbon Fibre Reinforced Polymer (CFRP) blade subcomponents.Secondly, novel adaptive methods of ultrasonic phased array operation and data analysis, employed using a new Multi-Aperture (MA), ultrasonic beam transmission and reception strategy, have been shown to increase imaging frame rates, resulting in the ability for increased inspection speeds and/or resolutions. An adaptive and autonomous MA firing sequence generator has been designed, specific to the sample and target defect size, with frame rate increases by a factor of 6.7 reported.Finally, the nature of an ultrasonic wave’s interaction with a composite’s non-homogenous and anisotropic internal structure has been used to determine both the Fibre Volume Fraction (FVF) as well as fibre orientation, in the third major contribution reported in this thesis. Data obtained was used as an effective screening technique to guarantee that these parameters, and thereby the mechanical performance of a composite, fall within the desired range. FVF values determined by this method were typically within 2 % of reference values, measured by a third party using conventional testing methods.
Advisor / supervisor
  • MacLeod, Charles Norman
  • Carroll, James
Resource Type