The paper presents a comparative analysis of non-destructive testing methods used in the assessment of welded joints. The authors describe the methodology of conducting tests on welded plates using the vibration method. On the basis of the FFT analysis of responses from accelerometers, spectral characteristics were calculated, and then used along with statistical measures to develop a comparative method in non-destructive testing of welded joints. This method will make it possible to quickly and easily distinguish plates with non-defective welded joints from plates with faulty welds. The paper presents test results for a non-defective plate weld (sample no. 2202), a plate with defective edge fusion (sample no. 2127) and one with a cracking along the entire sample length (sample no. 2132). The article points out the limitations of the proposed method and the need for further research
Among structural health monitoring (SHM) methods of thin-walled structures, a vibrodiagnostic method is one of the most promising. The accelerometer recorded responses provide diagnostic information that requires mathematical processing to extract the essential dynamic characteristics. The authors have been looking for new parameters - diagnostic benchmarks which can be applied to non-destructive, automatic testing of thin-walled marine structures (especially their welded joints) like ship hulls. All characteristics have been based on recorded data generated during the vibration tests of welded joints with and without failures. For this purpose, the authors proposed method based on: FFT windowing analysis, benchmark with using 2D or 3D time – frequency dynamic characteristics and the determination of damping decrement in function of time. The work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds.