Fluid viscous dampers develop a resisting force that depends on piston velocity. This calculator evaluates an entered constitutive-law magnitude at one speed and a constant-force path estimate; it does not simulate a motion history or structure.
Viscous Damper Interactive Calculator
Enter coefficient, positive speed magnitude, exponent and path length. Results are point evaluations of |F|=c|v|^alpha—not signed force, hysteresis, heat rise, cycle energy, structural response or damper qualification.
Equation Used
- c and alpha are entered phenomenological parameters and are not derived from device geometry or test data.
- Velocity is a nonnegative magnitude; force direction is omitted.
- Power is the instantaneous dissipated-power magnitude Fv at the entered speed.
- Path energy assumes constant force over the entered stroke and is not a cycle integral.
- Temperature, frequency history, fluid compressibility, accumulator, seals, pressure, cavitation, hysteresis, stiffness, mounting, structure, heat rejection, limits, strength, qualification and safety are omitted.
Velocity-Dependent Fluid-Damper Law
NIST-hosted seismic-protection references express fluid-damper force as C|v|^alpha sign(v), with alpha controlling nonlinearity and alpha=1 giving the linear case. This page evaluates magnitude only and does not reproduce a tested device.
What This Calculator Represents
The tool evaluates the entered constitutive-law magnitude at one speed, multiplies by speed for instantaneous dissipation magnitude, multiplies by entered path for a constant-force work estimate, and shows cv for comparison.
Point Evaluation and Path Estimate
|P|=|F||v|
constant-force path estimate=|F|s
linear comparison=cv
Signed resisting force is −c|v|^alpha sign(v). Real cycle energy is the path integral of force, not generally F times full stroke.
Worked Point Example
For c=5,000 N/(m/s)^alpha, v=0.25 m/s, alpha=1 and s=0.10 m, force magnitude is 1,250 N, instantaneous dissipation magnitude is 312.5 W, constant-force path estimate is 125 J and the linear comparison is 1,250 N.
Model Boundary
- Calculated: one constitutive-law point, instantaneous Fv magnitude, constant-force Fs estimate and linear comparison.
- Illustrated: a generic piston, fluid chambers and orifice-flow cue.
- Not calculated: signed time history, hysteresis, actual cycle energy, temperature, pressure, cavitation, seals, accumulator, stiffness, structural response, qualification or safety.
Frequently Asked Questions
Is the force signed?
No; the calculator reports magnitude.
Is F times stroke energy per cycle?
No; it is a constant-force one-path estimate.
Why show cv?
It shows the alpha=1 calculation using the same coefficient number. The units of c depend on alpha, so this is a numerical comparison rather than a conversion between physical dampers.
Are c and alpha predicted?
No; they are entered.
Are temperature and pressure included?
No.
Can this select or qualify a damper?
No.
References
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