Session: Virtual Presentations in Acoustics, Vibration, and Phononics

Paper Number: 97130

97130 - Ultrasonic Guided Waves Nondestructive Damage Detection for Square Steel Pipe Based on Semi-Analytical Finite Element Method 

Steel structure has a wide range of applications in civil engineering, and especially, square steel pipe, as the main form of steel member, has good mechanical properties and can meet the practical demand in different situation, such as concrete filled steel tubes and truss rods. However, in actual engineering applications, square steel tubes are affected by loads and environmental factors, which will inevitably lead to local damage and endanger the safety of the overall structure in operation. Therefore, to ensure the structural safety of buildings and machinery, nondestructive testing and structural health monitoring are indeed necessary for square steel pipes.

Ultrasonic guided wave (UGW) non-destructive testing technology is an efficient means for damage identification and has been applied widely in the field of detection for pipelines, railway tracks, steel, ships and aircraft. Besides, the dispersion curves of the guided waves in a square steel pipe are indispensable reference for the integrity test of continuous structural components, which represent the frequency dependence of guided wave velocities. Unfortunately, the complete dispersion curve of ultrasonic waves in square steel pipes cannot be solved by the traditional finite element modal analysis method.

To address the problem, the semi-analytical finite element (SAFE) method was used to obtain the ultrasonic guided wave dispersion curves in a square steel pipe, on this basis, a UGW-based non-destructive testing strategy is proposed. Firstly, triangular elements are adopted to perform the finite element discretization on the cross-section of the square steel pipe, and the guided wave is assumed to be in a harmonic motion along the wave propagation direction. Then, the wave equation of the ultrasonic guided waves propagating in the square steel pipe is deduced theoretically, through solving the characteristic equation, the wave number and frequency can be obtained, and the relation between the frequency and phase velocity & group velocity is obtained; thus, the dispersion curves can be plotted, which can be used to analyze the vibration characteristics of the guided wave modals. Afterwards, the optimal excitation frequency, excitation direction and excitation location are selected based on dispersion property for the different damage modes of the square steel tube. Lastly, the proposed damage identification method is validated through numerical simulation and experiment. The results show that the dispersion curves of square steel pipe solved with the semi-analytical finite element method are in good agreement with the actual test data, besides, for the damage on the long edge, short edge and corner of the square steel tube cross-section, the reflected guided wave package can identify the damage location effectively under the selected excitation.

Presenting Author: Tingting Yang Harbin Institute of Technology

Presenting Author Biography: Ms. Tingting Yang is a Ph.D. student of Harbin Institute of Technology. Her research interest is guided wave based damage detection.

Authors:

Tingting Yang Harbin Institute of Technology
Wensong Zhou Harbin Institute of Technology