Nigel Garland

Material characterisation to understand various modes of corrosion failures in large military vehicles of historical importance

Large military vehicles within museum collections are stored in two distinct environments, controlled and uncontrolled, with an intermittent transitional mode where vehicles travel between the two. Variable environmental conditions combined with operational factors pose significant risks to the reliability, durability and longevity of these vehicles. Although there are methods for retarding or decelerating aspects of failure, to maintain the integrity and originality of these vehicles as artefacts a sustainable methodology for conserving these vehicles should be developed. Corrosion is one of the significant contributors to the structural damage and material aging of historical military vehicles; therefore an experimental study was conducted to understand the prevailing mechanisms of failures due to corrosion with various types occurring in these vehicles identified. This paper presents various modes of corrosion in historic vehicles while X-ray Fluorescence and ultrasonic scanning corrosion mapping techniques characterise corrosion inhibiting materials and subsequent material loss. Understanding material profiles and their link to environmental exposure during use and non use of these vehicles will lead to a sustainable methodology for their conservation.

Experimental Sliding Performance of Composite Tip Seal with High-Carbon Steel Plate under Lubricated Conditions Applied to Scroll Expander Systems

This study is focused on the radial leakage points between the bottom steel plate and the composite tip seal of a scroll expander device. The critical components of the scroll expander were thoroughly studied with the use of a TE 57 sliding microfriction machine under different lubrication regimes and examined from the perspective of both friction and wear. Various friction graphs were produced using different load, speed, and temperature combinations adjusted to simulate the expanders operating conditions. The wear analysis showed that a higher contact load can enhance the performance of the scroll expander, lowering the wear rates and simultaneously reducing the leakage paths. Surface analysis revealed the wear damage mechanisms of the scroll steel plate and highlighted the tribological performance of the tip seal.