Impulse excitation technique

<p>The impulse excitation technique (IET) is a non-destructive material characterization technique to determine the elastic properties and internal friction of a material of interest. It measures the <a href="/facts/Fundamental_frequency/TJBJKHow">resonant frequencies</a> in order to calculate the <a href="/facts/Young%2527s_modulus/MV5JMCIM">Young's modulus</a>, <a href="/facts/Shear_modulus/9e9IvJnz">shear modulus</a>, <a href="/facts/Poisson%2527s_ratio/ppIsaujA">Poisson's ratio</a> and <a href="/facts/Friction/d0108Rpu">internal friction</a> of predefined shapes like rectangular bars, cylindrical rods and disc shaped samples. The measurements can be performed at room temperature or at elevated temperatures (up to 1700 °C) under different atmospheres.
</p><p>The measurement principle is based on tapping the sample with a small projectile and recording the induced vibration signal with a <a href="/facts/Piezoelectric_sensor/vSuskfmd">piezoelectric sensor</a>, <a href="/facts/Microphone/7YWGlXCl">microphone</a>, <a href="/facts/Laser_Doppler_vibrometer/bB0UaLrn">laser vibrometer</a> or <a href="/facts/Accelerometer/xxrXzrlI">accelerometer</a>. To optimize the results a microphone or a laser vibrometer can be used as there is no contact between the test-piece and the sensor.  Laser vibrometers are preferred to measure signals in vacuum. Afterwards, the acquired vibration signal in the time domain is converted to the frequency domain by a <a href="/facts/Fast_Fourier_transform/caT7UUCh">fast Fourier transformation</a>. Dedicated software will determine the resonant frequency with high accuracy to calculate the elastic properties based on the <a href="/facts/Euler%25E2%2580%2593Bernoulli_beam_theory/3DyQV9do">classical beam theory</a>.
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Impulse excitation technique open-in-new

Impulse excitation technique