Impulse excitation technique
The impulse excitation technique (IET) is a nondestructive material characterization technique to determine the elastic properties and internal friction of a material of interest. It measures the resonant frequencies in order to calculate the Young’s modulus, shear modulus, Poisson’s ratio and internal friction of predefined shapes like rectangular bars, cylindrical rods and disc shaped samples.
Advantages impulse excitation technique
 Nondestructive measurement of elastic and damping properties
 Large temperature range: 50 °C – 1700 °C
 Reliable, fast and easy accessible measurement technique
 Limited restrictions on sample geometry and dimensions
 Applicable to porous and brittle materials due to small strains
 Information about internal structure, global behavior, damage,…
Elastic properties
Different resonant frequencies can be excited dependent on the position of the support wires, the mechanical impulse and the microphone. The two most important resonant frequencies are the flexural which is controlled by the Young’s modulus of the sample and the torsional which is controlled by the shear modulus for isotropic materials. For predefined shapes like rectangular bars, discs, rods and grinding wheels, the dedicated software calculates the sample's elastic properties using the sample dimensions, weight and resonant frequency (ASTM E187615).
Young's modulus
Shear modulus
Poisson ratio
Internal friction
Application domains
Relevant IET standards

ASTM standards
 ASTM E187615: Standard Test Method for Dynamic Young's Modulus, Shear Modulus, and Poisson's Ratio by Impulse Excitation of Vibration
 ASTM C125915: Standard Test Method for Dynamic Young’s Modulus, Shear Modulus, and Poisson’s Ratio for Advanced Ceramics by Impulse Excitation of Vibration
 ASTM C154802(2012): Standard Test Method for Dynamic Young's Modulus, Shear Modulus, and Poisson's Ratio of Refractory Materials by Impulse Excitation of Vibration

ISO standards
 ISO 126801:2005: Methods of test for refractory products  Part 1: Determination of dynamic Young's modulus (MOE) by impulse excitation of vibration
 ISO 20343:2017: Fine ceramics (advanced ceramics, advanced technical ceramics)  Test method for determining elastic modulus of thick ceramic coatings at elevated temperature

EN standards
 EN 8432:2006: Advanced technical ceramics  Mechanical properties of monolithic ceramics at room temperature  Part 2: Determination of Young's modulus, shear modulus and Poisson's ratio
 EN 8205:2009: Advanced technical ceramics  Thermomechanical properties of monolithic ceramics  Part 5: Determination of elastic moduli at elevated temperatures