Estimating viscoelasticity of pipes with unknown leaks

This paper develops a transient wave-based method to estimate the viscoelastic parameters (VEPs) of a pipe where unknown leaks may exist. The proposed method exploits the fact that the time instants at which the transient pressure signal crosses the steady-state pressure signal is independent of leaks and dependent on VEPs. It is demonstrated that the resulting optimization problem is convex, i.e., the convergence to the optimal VEPs is guaranteed. Numerical and experimental results illustrate that the transient model with estimated VEPs (obtained from leaking-pipe data) accurately replicates the transient behavior of the pipe.