Corrosion mapping of historic military vehicles using the TD Focus-Scan
16/12/2010
The Tank Museum Bovington has the largest collection of military tanks from World Wars 1 and 2 and recent conflicts. These historic military vehicles and all other large objects have always been key entities, which provide a wealth of information and insight into the past design process, design methods, materials and manufacturing techniques. These rare and historic collections are valuable assets for our future generation. These historic vehicles, like any other museum artefacts, are associated with deterioration due to ageing mechanisms such as corrosion, cracks and wear.Large military vehicles such as military tanks were exposed to extreme physical and environmental conditions during the war; in addition, after the war the vehicles were left unattended for an unidentified period in an uncontrolled environment resulting in accelerated ageing mechanisms. Corrosion is one of the growing persistent problems in the vehicles at the Tank Museum Bovington. The historic vehicles are stored in the museum in two distinct controlled and uncontrolled environments, with a transitional mode when vehicles move between the two. Varying environmental conditions together with operational factors pose a significant risk to the vehicles.
To preserve these vehicles in a valuable state for the benefit of society, sustainable conservation techniques are required to slow or suspend the deterioration within these historic vehicles.
The extraordinary interests and efforts of the Director of the Tank Museum, Mr Richard Smith, led to the design of a research project between the Sustainable Design Research Centre at Bournemouth University and The Tank Museum Bovington. The research project is supervised by Dr Zulfiqar Khan, Dr Nigel Garland and Dr Martin Hind while Mr Adil Saeed is the researcher.
The aims of the research are to identify the ageing mechanisms such as corrosion, cracks, undesired stresses and other potential risks through non-destructive methods and develop sustainable methodology for the preservation of historic vehicles in different museum environments. Corrosion has been identified as one of the major contributors to the structural damage and material ageing of the historic military vehicles. Non-destructive methods such as ultrasonic scanning are vital to map and measure the corrosion in these vehicles and thus keep their cultural biography with minimum interference.
For this purpose, an experimental study was conducted by the Sustainable Design Research Group together with AGR Technology Design to understand the prevailing mechanisms of failure due to various modes of corrosion. To show their support to British historic heritage and academia, Mr Mark Clark, AGR’s General Manager, and Mr Mark Nel, Applications Advisor at AGR Technology Design, provided unconditional support and complimentary use of the TD Focus-Scan to map corrosion and associated material loss. The system is designed to map corrosion using multi-channel phased array, time-of-flight diffraction (TOFD) and pulse echo techniques.
Samples from historic military tanks (M10, Sherman and Centaur) were brought to and investigated at AGR Technology Design for material loss due to corrosion. The ultrasonic scan revealed a staggering material loss due to corrosion and surface anomalies in the samples. The statistics obtained will be used to recommend protective mechanisms to decelerate or suspend the corrosion process. The TD Focus-Scan has shown great potential for future use in the museum environment to map corrosion, identify cracks and other surface and subsurface anomalies. The TD Focus-Scan has shown the ability to be used in the museum on a smaller as well as larger scale for condition monitoring non-destructively and cost effectively. The work among The Tank Museum Bovington, Bournemouth University and AGR Technology Design will not only benefit the valuable assets in the museums but will open new opportunities in the public sector and industry.
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