Non-destructive testing and assessment of dynamic incompatibility between third-party piping and drain valve systems: an industrial case study

Abstract

This paper presents the outcome of an industrial case study that involved condition monitoring of piping system that showed signs of excess fatigue due to flow induced vibration. Due to operational requirements a novel non-destructive assessment stratagem was adopted using different vibration analysis techniquessuch as Experimental Modal Analysis (EMA) and Operating Deflection Shapes (ODS) -and complemented by visual inspection. Modal analysis performed near a drain valve showed a dynamic weakness problem (several high frequency flow induced vibration frequency peaks) hence Condition Based Monitoring (CBM) was used.This could easily be linked to design problem associated with the dynamic incompatibility due to dissimilar stiffness between two 3 rd party supplied pipe and valve systems. It was concluded that this is the main cause for these problem types especially when systems are supplied by third parties, but assembled locally, a major cause of dynamic incompatibility. It is the local assembler's responsibility to develop skills and expertise needed to sustain the operation of these plants. This paper shows the technique used as result of one such initiative. Since high amplitude, low frequency displacement can cause low cycle fatigue, attention must be paid to ensure flow remains as steady-state as possible. The ability to assess the level of design incompatibility and the level of modification required using non-destructive testing is vital if these systems are to work continuously.

On a mathematical model in estimating the reliability of technological equipment by non-destructive testing

“…Contemporary ways for analyzing the industry objects of responsible purposes under exploitation consist in using non-destructive testing techniques [1] in various worldwide spheres of diagnostics of objects such as industrial and civil buildings, industrial piping systems, concrete bridges, nuclear power facilities [2][3][4][5][6][7] at al. Among these techniques the acoustic emission (AE) method takes the especial place when estimating the predestructive stages of exploited equipment material since AE method permits to detect growing defects being just the most dangerous [8,9].…”

“…Compactness of the operator of that system allows to represent its operator as the sum of finite-dimensional and infinitesimal ones. This fact permits to apply various numerical methods to solve the equations with compact operators and hence to solve input boundary value problem (2).…”

“…) is based on reducing one to the corresponding boundary integral equation system by constructing Green function condition(2). Hereby, there takes place the representation for the complex amplitude in the form of curvilinear integrals along right boundaries of cuts  Let us place the observation point (x,y) on the cut boundaries  and go over to the local coordinates along the boundaries  .…”

Non-destructive testing and assessment of a piping system with excessive vibration and recurrence crack issue: An industrial case study

“…Kong et al investigated flow induced vibration problem of in-service duplex stainless steel piping system as well as the third party piping and drain valve system of an offshore gas processing platform. Vibration analysis was performed in identifying structural dynamics issue of the third party piping and drain valve system and the results showed that there was design problem due to dissimilar stiffness and dynamic incompatibility between the supplied pipe and valve systems [13]. By combining both experimental and computational techniques, flow -induced vibrations and maximum dynamic stresses were calculated and the highest flow rate for the piping system to run under the allowable endurance stress limit and safe condition was forecasted [14].…”