FEA numeric solution of wave equation indicates that deductions must comply with acoustic parameters such as velocity of sound

amplitude

wave shape etc. when inspecting interior flaws of grout of anchor bar. Basing on wavelet packet analysis

energy eigenvector is a flaw vector

which could be regarded as basis in anchors' non-destructive inspection. As a nonlinear dynamical system

artificial neural networks dealing with quality inspection of gray system have been proved efficient.