An improved approach to evaluating pile length using complex continuous wavelet transform analysis

Sheng Huoo Ni, Ji Lung Li, Yu Zhang Yang, Zih Tong Yang

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Non-destructive testing has been used widely for the integrity testing of piles, especially low-strain testing methods, for example the sonic echo test, the impulse response method, etc. The length of a long pile is often difficult to evaluate correctly due to the fact that the energy of a reflected stress wave generally fades with the wave travel path during testing. The purpose of this paper is to use the three-dimensional amplitude and phase angle message of a complex continuous wavelet transform to determine the length of piles by analysing a time-frequency phase angle diagram. Five piles of different lengths were tested to verify the new approach used in this study. The testing results show that a complex continuous wavelet transform is not only able to provide high-resolution results in different frequency bands but can also simplify the identification of the reflection point using the three-dimensional phase angle spectrum. The pile length and pile tip condition can be easily determined using a phase angle diagram under the corresponding frequency of maximum amplitude in the three-dimensional amplitude spectrum.

Original languageEnglish
Pages (from-to)318-324
Number of pages7
JournalInsight: Non-Destructive Testing and Condition Monitoring
Issue number6
Publication statusPublished - 2017 Jun

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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