MEASUREMENT AND DIAGNOSTICS

The MBLL has a wide range of diagnostic tools for the measurement and analysis of lightning direct effects phenomena. We also have expertise in designing and developing sensors and test techniques to meet demanding research needs. Our existing diagnostic capabilities include:

 

 

Transducers: Robust systems for high-speed measurement of current (current transformers, rogowski coils, resistive shunt), floating and differential voltage measurement, pressure and temperature monitoring. A range of high-speed scopes and data-acuisition systems are used to log the resulting data

 

 

CT   VT
Scopes

 

 

 

Imaging: We use a range of visual and thermal imaging systems, including high resolution still cameras, high speed monochrome camera (up to 775,000 fps) and laser illumination system, and a pair of research grade thermal cameras. Examples of our high speed video capture capabilities can be found here.

 

  

Strike to Carbon 1   Strike to Carbon 4

High speed camera stills from 'D' waveform arcs applied to a CFRP test panel

 

 

Light Analysis: Spectral analysis of lightning arcs and secondary emission events is performed using complimentary UV-Visible and Near-Infrared spectrographs. The information generated helps us to understand the physical and chemical processes occurring during the strike. Instantaneous arc intensity is recorded using a photodiode-based transient light measurement system. 

 

 

AllPeaks  
Image 5000  

Emission spectrum of a calibrated spark generator used for verification of aircraft fuel ignition threshold

 

 

 

Mechanical: In addition to electrical heating effects, a direct lightning attachment to a structures results in significant localised and short-lived mechanical loading, causing deflection of the structure and shckwave propagation. Ongoing research at MBLL has devleoped a number of diagnostic systems for quantifying these processes

 

 

Defleciton1    Deflection 2 

 

Deflection measurement by point displacement evaluation and regular surface grid patterning 

 

 

 

 

Post-strike analysis: We also have a number of post-strike diagnostic facilities, to give us a detailed insight into the physical processes and damage mechanisms occurring during a test. Capabilities include: Sample sectioning, mounting, polishing, pc-driven conventional and inverted microscopy, electron microscopy and energy-dispersive x-ray (EDX) spectroscopy. These tools also find use in research outside the MBLL, with some examples shown below.

 

 

 

Microscopes CopperCable p01c1 AL Crazing
SEM ZnOVar x1000
Mounted ECF Drilled Copper Mesh

 

From left to right: TOP (microscopy suite, cross-section of a stranded copper conductor, electrical discharge patterning on an aluminium electrode), MIDDLE (SEM suite, Zinc-Oxide field-control microvaristor embedded in a silicon rubber insulator, torn end of an 80-micron Nickel-Chromium inititation wire), BOTTOM (sectioned and mounted samples,expanded copper foil on a CFRP sample, close up of ECF showing detail of the woven GRP protective layer)

 

 

Diagnostic Development

The development of bespoke measurement systems forms an integral part of the laboratory's research activity. We will be more than happy to discuss your specific test requirements