Quality assesment of welded joints using the logarithmic distribution analysis of amplitude spectrums calculated time window method

Abstract

In continuous monitoring systems of welded joints of thin- walled structures, a vibrodiagnostic method is the most promising. Its most important advantage is that it is effective and offers the greatest real-time research capabilities. It is used in classic NDT techniques as well as in construction monitoring during operation. This work presents a measurement method of dynamic characteristics of the structure with the use of piezoelectric sensors. The article presents the assumptions concerning the evaluation of welded joints using the analysis of the logarithmic distribution of the amplitude spectrums calculated by the time window method. The statistical measure used in the form of the mean value is a proposed parameter, which analysis for a given welded joint may enable an unambiguous assessment of its quality. Attention was paid to the elements important for the study and they included a calculation algorithm and the sample results from the proposed method used for some selected plates with different welds. The work contains the description of the stand to register dynamic characteristics in case of welded joints. The results of the tests show that the analysis of the logarithmic distribution value for amplitude spectrums calculated by the time window method indicates that they differ markedly depending on the welds, indicating their quality and defects which are associated with them.

Keywords

• diagnostics
• welded joints
• non-destructive test- ing
• NDT
• SHM
• vibration