Impulse excitation technique and its application for identification of material damping: an overview

Abstract

The recent work presents an overview of the papers devoted to the application of Impulse Excitation Technique (IET) for the measurement of internal friction in different materials. IET is an advanced method to measure such materials’ characteristics as Dynamic Young’s and Share Moduli, Dynamic Poisson’s Ratio, Damping, to investigate the deformation behavior, softening phenomena and relaxation mechanisms and phase transformations in different materials. The experimental studies can be performed at both, room and high temperatures. Due to its simplicity, low cost, high accuracy and reproducibility it may take the leading position among the other non-destructive testing methods and techniques.

Temperature Effect on the Dynamic Young’s Modulus, Shear Modulus, Internal Friction, and Dilatometric Changes in Quenched and Annealed AISI4130 Steel

“…Therefore, measurements of E and G are of great help in studying phase transformations in steels. Anomalous behavior of the elastic properties was also found in Fe-based alloys with RMT: Fe-Cr-Ni, Fe-Mn, Fe-Ni-Co-Ti [23], carbon steels, and stainless steels [9,[12][13][14][15]24].…”

“…Electromagnetic, piezoelectric, electrostatic, electrodynamic, mechanical, and other methods can also be used to excite vibrations in the sample for the determination of the dynamic modulus of elasticity [3]. Nowadays, many researchers are using Ultrasonic and Impulse Excitation Techniques as non-destructive testing to evaluate the mechanical properties of metallic materials [2][3][4][5][6][7][8][9][10].…”

“…In particular, the Impulse Excitation Technique (IET) has been highlighted as a straightforward, non-destructive, and fast method for the determination of the elastic constants and damping characteristics of different classes of materials [5][6][7][8][9]. The IET is based on the acoustic response in free vibration, after an initial impulse, of the material whose elastic properties are to be determined [10].…”

Measurement of natural frequency and mechanical damping of thin brass diaphragm by pulsed laser generated vibrations

“…Measurement of mechanical damping and resonance frequencies of flexural and torsional modes separately in IET [12] is also used to determine the elastic properties of different types of materials [13]. Fast Fourier Transformation (FFT) based frequency response, Finite Element Method (FEM) based numerical and complex empirical relations are used in RUS and IET for the determination of parameters that are restricted to certain geometries, sample sizes, and free boundary conditions [12], [13]. IET requires the sample to hold in free vibration without clamping with certain predefined dimensional and boundary conditions.…”

“…Vibrations are generated on a surface under the influence of impulsive or dynamic loadings. Different types of mechanical hammers and piezoelectric transducers are conventionally used as contact based vibration generators [12]. Short duration laser pulse focused on the surface of the target can also induce vibrations without any contact.…”