A NOVEL IMAGE PROCESSING METHOD FOR ARCMAC POINT TO POINT OPTICAL STRAIN MEASUREMENT

摘要

The remaining life of high pressure steam pipes in power stations is heavily dependent upon material creep rates. Monitoring strain in these pipes is difficult due to demanding operational conditions and has resulted in the development of a rugged optical strain gauge system by E.ON UK. The E.ON UK auto-reference creep management and control (ARCMAC) gauge is a point-to-point biaxial creep strain measurement technique. Room temperature validation of the gauge was done using a UK National Physical Laboratory (NPL) extensometer calibration rig (ECR). These gauges have been successfully installed and measurements have been acquired on high temperature (～600 °C) low-alloy ferritic steel power plant piping. In conjunction with the ARCMAC gauges, research has been ongoing to seek effective methods to process the corresponding ARCMAC images. This paper describes a novel image processing method for the analysis of ARCMAC images. This method processes ARCMAC images with high efficiency and accuracy even if images were taken in demanding environmental conditions. This novel image processing method has been developed into a standalone software program named ARCMAC Assistant to assist both experiment and field work. Experiments involving calibration test work and in-situ creep tests have been used to validate its accuracy.