Low Energy, High Resolution X-Ray Computed Tomography

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Back to Core Research Programme AMorph – 4D Printing for Field Morphing Structures Automation of Composite and Hybrid Joining Process Coaxial Wire Additive Manufacturing Processes and In-Line Monitoring Tools Development of Coded Excitation Technique for Non-Metallic Pipes Inspection Development of Digital Twin technology as a demonstrator for real-time integrity assessment of crack growth in tensile specimens Development of Friction Stir Welding (FSW) for Hydrogen Fuel Storage Tanks Development of Leak-Before-Break Hydrogen Storage Composite Pressure Vessels With Polymeric Liner Establishing Assessment Methods for Determining Safe Service Limits of High-Temperature Materials in Extreme Environments Fracture toughness in aggressive environments: effect of crack monitoring techniques on test results In-process detection and non-destructive testing of electron beam weld imperfections Internal Bore Coatings for Applications in Corrosion and Hydrogen Environment Joining of Additively Manufactured Materials Long term behaviour of polymeric liner materials/coatings in hydrogen service Techniques for High Temperature Ultrasonic Inspection of Arc Welding Ultimate Leverage Fund

Project Code: 0901-12

Objectives

The project will have the following objectives:

Determine the requirements and feasibility of using low energy, high resolution microfocus x-ray computed tomography to detect and assess porosity and fibre waviness within CFRP components.

Identify and integrate the hardware and software improvements necessary to meet these requirements.

Investigate and assess the detectability of porosity and fibre waviness using the developed system.

Derive a methodology for procedure development for low energy, high resolution micro focus computed tomography.

Project Outline

The project will have the following stages:

Procure reference samples.

Research, acquire and integrate a new high-resolution detector

Integrate new detector with existing software and hardware.

Carry out trials with new system with industrial standard comparators

Carry out trials on samples to establish limits of delectability and assess porosity and fibre waviness.

Section a number of samples to verify inspection results

Develop sample inspection procedure

A number of CFRP reference samples of varying thickness will be procured from member companies. These samples will be taken from batches of material with known porosity and fibre waviness determined by micro sectioning. These samples together with microfocus 2D radiography will be used to determine the requirements of the CT system.

The 225kV HMX CT system housed at TWI Wales has an operational range of 40 to 225kV. This system will be modified in order to allow the detection of very small defects such as porosity around and fibre waviness occurring within the composite material. To achieve the performance requirements previously determined, performance of the source will need to be optimised in order to enable stable operation at around 20kV while attaining a focal spot size of 5 m.

Once the source has been optimised a high resolution flat panel detector will be procured and integrated within the cabinet system. This will include integration of the new detector software with the CT data acquisition algorithms. The performance improvements to the system will be determined and its performance determined using international standard comparators such as wire IQIs and line pairs.

The system will then be used to evaluate the reference samples with known porosity and fibre waviness defects and the limits of reliable detection will be determined for a range of material types and geometries.

Blind trials will be carried out on further samples taken from current production lines and the porosity and fibre waviness will be assessed. The results will be compared with data from the manufacturers obtained using conventional inspection methods such as UT. A selection of samples will be sectioned in order to verify the accuracy of the CT inspection data.

Finally an example procedure will be developed and included with the final reporting.

Relevant Industry Sectors

Aerospace

Technical and Economic Benefits

The project will have the following technical and economical benefits:

Increased business opportunities for high resolution inspection and analysis of composite and other materials

Members will be able to meet targets for quality and identify defects quickly and with confidence

Resulting SCP and GSPs for members interested in low density structures requiring high resolution inspection

Will help maintain TWIs position at the leading edge of CT capability

Industrial Member Report

Access the Industrial Member Report resulting from this programme.