Confidence in Composites

Last week TWI's Nathan Hartley presented an overview of the ACCURATe project at the "Confidence in Composites" event, organised by the leading UK industry trade association Composites UK and supported by the world's largest trade association serving the composites industry - the American Composites Manufacturers Association (ACMA).

The two day conference provided a showcase for the latest non-destructive evaluation and testing (NDE/T) technologies, structural health monitoring (SHM) techniques and approaches to repair for composite materials through case study presentations and demonstrations. It was attended by representatives from leading UK composite manufacturers and experts in NDE/T from industry and academia. 

Here's a photo taken during Nathan’s presentation which included an up to date account of project progress and some excellent images & videos of the system in action:

The presentation was well received and generated significant interest. For more information follow this link to the conference website. A full version of the presentation has also been added to the project website here.

Partner Site Testing Success!

In May 2019 ACCURATe project partners TWI, Kuka, Innolas and RECENDT completed the assembly of the prototype robotic LUT Inspection system at Kuka's manufacturing facility in Halesowen (Birmingham, UK). The assembly brought together all aspects of the system including the detection and generation lasers, fibre coupled laser head, interferometer, robot control system, 7-axis robotic manipulator and the UT data acquisition and analysis software. The prototype system was installed within in a temporary light proof safety enclosure for the purposes of testing. The photos below show the laser and robot systems assembled in the temporary safety enclosure and ready for test:

Following installation checks, commissioning and risk assessments, the initial tests were successfully carried out in early June 2019, demonstrating "proof of concept" for the proposed robotic LUT inspection technique. The tests verified that all aspects laser, robot, UT detection and data acquisition software systems all interact and function as expected. The next step is to complete the optimisation of the laser system and conduct a more intensive testing programme which will measure the full capabilities of the system. Here is a photo and video, both taken during the testing:

Progress Update - UT Detection System

The ultrasonic laser detection system, interferometer & laser head unit are provided by RECENDT. The interferometer is used to convert phase changes in the light backscattered from the sample surface to amplitude changes, which are measured via photodetectors. A two wave mixing (TWM) interferometer does the conversion by mixing a reference beam and the sample beam in a GaAs-crystal.

The photo below shows the final bench test of the detection system in action, with the laser head mounted on a moving stage to replicate the robot motion.

Progress Update - Laser System

Over the last few months the various subsystems of the LUT Prototype have been assembled and bench tested by the individual project partners. Here are some details of the Laser system provided by Innolas:

The laser system comprises a diode pumped solid state UT generation laser with a pulse length of about 10 ns, a wavelength of 532 nm and a repetition rate of 400 Hz and a detection laser, based on a single longitudinal mode (SLM) cw-laser which is guided through a diode pumped Nd:YAG laser rod.

Progress Update - Robot System

Over the last six months the various subsystems of the LUT Prototype have been assembled and bench tested by the individual project partners. Here are some details of the robot system:

The laser measurement system is mounted on a KR30-L16 Kuka Robot which is in turn mounted on a KL1000 Linear Track with rated travel of 2700mm. The system is controlled by a Kuka KRC4 robot controller and a bespoke, integrated control system which interfaces directly with the LUT system, providing the control signals for operating the lasers. The photograph below shows the robot system fully assembled prior to installation of the safety enclosure:

First bench test results show great promise!

In November 2018, the software system was bench tested in conjunction with the laser UT detection system at RECENDT’s laboratory in Linz (Austria). The tests were a complete success and demonstrated that UT data could be acquired by the system and displayed, recorded, processed and analysed using the TWI software. The screenshot below was taken during this testing phase and shows a typical A & B scan response for an aluminium test block:

TWI software development progressing well

The Data Analysis & Visualization software is provided by TWI Technology Centre (Wales). The software is based on a package previously developed specifically for robotic UT data acquisition and analysis for use in the inspection of aerospace components. This previous work has been limited to ultrasonic phased array and conventional ultrasonic data acquisition only. Using this as a baseline, TWI are developing a new software application with extended hardware integration to support Laser UT data acquisition, analysis and visualisation of inspection results. Development is progressing well. A typical example screenshot of the software user interface is shown below: