Use of Microwave (MW) frequencies for NDT of non-metallic pipes.
Microwaves (MW) are part of the electromagnetic spectrum with wave lengths in the centimeter range and frequencies from 0.3 to 300 GHz. The basic operating principle of this technology is based on the backscattering of microwaves as they travel from one media to another media with different dielectric constant. So a defect in the non-metallic structures is viewed as a new media with a different dielectric constant from the surrounding material.
At the moment MW NDT although is a technique applied in laboratories and few commercial systems are available it hasn’t enjoyed wider field use. Also it is not standardised and several configurations are in use. Moreover with mapping and ranging needs for automated vehicles MW electronics have moved from defence applications to more mainstream industrial ones. This gives an opportunity to explore MW NDT configurations previously unavailable.
Use of MW radiation as a means of detecting defects will be evaluated applications to be considered could include steel-fused based epoxies (FBE), glass fibre – carbon fibre interface and/or polymer-metal interface.
The research will at least cover
• microwave interferometry,
• pulse – echo microwave detection and ranging and
• Vector Network Analyser based evaluation
The work is expected to involve
• Finite Element based microwave propagation simulations,
• antenna design optimisation (through simulation),
• electronics design and assembly (for board level instruments) &
• laboratory experimentation.
Materials for experimental testing will include, but won’t be limited to:
• Insulated pipes (liners)
• reinforced thermoplastic pipes (RTP and TCP) and
• reinforced thermosetting pipes (GRE).
The NIC sponsor will define the pipe(s) of choice in order to develop the technology.
The technology will be evaluated against state of the art immersion and phased array ultrasonic and radiographic methods including CT.
Work layout and responsibilities: The expertise of two TWI section will be combined for the delivery of this project: ACS will bring expertise in composites materials and initiation of surface waves across interfaces that exist in composite pipe products. NDT will bring the expertise of using bulk electromagnetic waves; as well as interpretation of the results to information about the integrity of the structure and possible location of defects. The following bullets form an initial layout of the proposed research.
• Identification of interfaces of interest based on the selected pipe products (from NIC sponsor)
• Design of pipe digital twin (ACS – BU). Mechanical properties to be included in the model
• Design of transducer/antenna through Electromagnetic simulations (BU)
• Testing of transducers/antennas using VNA (ACS)
• Design of DAQ for signal interpretation (ACS-NDT-BU)
• Construction of DAQ system (NDT-BU)
• Manufacturing of interfaces (flat geometry) for initial tests and small tubes for technology demonstrator (ACS)
• Correlation of signals to defects (type of defect, location) (NDT)
NSIRC is a state-of-the-art postgraduate engineering facility established and managed by structural integrity specialist TWI, working closely with, top UK and International Universities and a number of leading industrial partners. NSIRC aims to deliver cutting edge research and highly qualified personnel to its key industrial partners.
About University: Brunel University. Brunel Composites Innovation Centre (BCC)
BCC has been carrying out research in phenomena that take place at the interface of composite structures with other materials (hybrid joints). BCC is also currently doing research in communications in composite pipes for the Oil & Gas sector utilising TWI’s Surflow® technology (using surface waves to transmit information through the composite)
Candidates should have a relevant degree at 2.1 minimum, or an equivalent overseas degree in Mathematics, Physics or Electronics Engineering.
This project is funded by TWI and academic partners. The studentship will provide successful Home/EU students with a stipend of £16k/year and will cover the cost of tuition fees. Overseas applicants are welcome to apply, with total funding capped at £24k/year.