Quantification and localization of internal pipe damage

Simplified Ultrasonic Damage Detection in Fluid-Filled Pipes

“…Whereas R dam was insensitive to the medium, R dam 'is more sensitive than R dam for a liquid filled pipe. The fits shown are trend lines: the relatively large amount of scatter derives from the fact that although severely dampened there are residual modes still present in our signal as we have previously shown [13][14][15]. R dam ' displays much more scatter than R dam .…”

“…This is related to the difference in resistance to shear at the inner and outer boundary of the thin wall. Different fluids at the inner and outer wall yield a stress gradient in the (membrane-like) wall, leading to the wave generation of flexural modes [13][14][15]. These fluidinduced vibrations add to the apparent high shear damping for different inner/outer fluids in flexible structures, such as our thin-walled pipe.…”

“…Each collar contains up to 16 signal sensors. We have shown that this can be reduced by >90% and also made to work over a much longer pipe length [13][14][15] thus simplifying the overal configuration of such a detection system. This used the simplest acoustic mode, the so-called T(0,1) which has been shown to predominate in pipe transmission and to be dispersion free.…”

Least squares deconvolution for leak detection with a pseudo random binary sequence excitation

“…8effectively minimises the energy of the impulse response, h 2 2 , and simultaneously minimising the least squares error term, defined by y − Xh 2 2 . Increasing the value λ effectively increases the weighting on regularisation h 2 2 , which suppresses the interference energy at the resultant IRF. This comes at the expense of a higher least squares error defined by y − Xh 2 2 .…”

“…been growing attention to address this and many techniques for pipeline defect detection and condition assessment have been proposed [1,2]. Typical defects of an aging pipeline include the leaks, blockages and internal and/or external corrosion in the pipes.…”