mechanical impedance


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Mechanical impedance

For a system executing simple harmonic motion, the mechanical impedance is the ratio of force to particle velocity. If the force is that which drives the system and the velocity is that of the point of application of the force, the ratio is the input or driving-point impedance. If the velocity is that at some other point, the ratio is the transfer impedance corresponding to the two points.

Mechanical impedance is a complex quantity. The real part, the mechanical resistance, is independent of frequency if the dissipative forces are proportional to velocity; the imaginary part, the mechanical reactance, varies with frequency, becoming zero at the resonant and infinite at the antiresonant frequencies of the system. See Forced oscillation, Harmonic motion

mechanical impedance

[mi′kan·ə·kəl im′pēd·əns]
(mechanics)
The complex ratio of a phasor representing a sinusoidally varying force applied to a system to a phasor representing the velocity of a point in the system.
References in periodicals archive ?
The ankle mechanical impedance is a dynamic operator that maps the time-history of angular displacements onto the corresponding time-history of ankle moments.
Ankle mechanical impedance may provide an opportunity to better characterize ankle dynamics.
This portable multimode adhesive bond testing instrument uses pitch-catch modes, mechanical impedance analysis (MIA), and resonance technologies to inspect materials that are commonly used in aerospace, energy, and automotive industries.
Its basic model includes all pitch-catch modes while the BondMaster 600M multimode model features all three bond testing inspection modes including resonance and mechanical impedance analysis.
Basically, the vibration is the result of the relationship between acting force during machine operation and mechanical impedance considered relatively steady, force variation being responsible for vibration fluctuation, therefore for machine's operating condition changes.
The method is based on measuring the mechanical impedance of a sample.
Because a DMA's three and velocity can be varied independently across a wide range (by altering the length, width and thickness of the piezo crystal beam, and by adding any necessary beams), the exciter's mechanical impedance can be adjusted in a manner unachievable with conventional moving coil or piezoelectric exciters.
Thus, E' is assumed to be directly related to the storage portion, S, of the mechanical impedance of the tip-sample contact in the dynamic model (see Fig.
Sumali, "Application of a Strain Gauge Array to Estimate Soil Mechanical Impedance On-The-Go," Transactions of the ASAE, Vol.
A relatively young ISO 9001 certified company, Sonotron NDT designs, manufactures, and markets non-destructive test (NDT) equipment and technologies for ultrasonic inspection, mechanical impedance analysis (MIA) and eddy current implementations.
All these aspects of ankle function may be characterized by its active and passive mechanical impedance, i.
A vertical smooth blade with an array of strain gauges was designed to dynamically measure mechanical impedance of soil at multiple depths.

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