Tutorial:
Vibration Control Unit Conversion Charts and Constants

This technical reference details acceleration, displacement, frequency, compliance, pressure, and temperature along with conversion charts.

Sinusoidal Motion (zero-peak)

Displacement (D)
(in.)
Velocity (V)
(in./sec)
Acceleration (A)
(g)
Displacement (D)
(in.)
D = 0.159 V/ƒ D = 9.78 A/ƒ2
Velocity (V)
(in./sec)
V = 6.28 ƒD V = 61.4 A/ƒ
Acceleration (A)
(g)
A = 0.102 ƒ2D A = 0.0163 ƒV

ƒ = frequency, Hz

Sinusoidal Wave Forms Multiplier x (A = xB)

Peak Peak to Peak RMS Average
B
A Peak 1 0.5 1.414 1.570
Peak to Peak 1 1 2.828 3.140
RMS 0.707 0.354 1 1.110
Average 0.637 0.319 0.901 1

Decibel Scale

dB Gain
60 1000
40 100
20 10
10 3.16
6 2.00
3 1.41
1 1.12
0 1.0
-1 0.891
-3 0.708
-6 0.5
-10 0.316
-20 0.1
-40 0.01
-60 0.001
dB = 20 log (Vout/Vref)
Vout = log-1 (dB/20)
Ref Gd Peak to Pk-S
Average Value = 0.637 x Peak Value
RMS Value = 0.707 x Peak Value
Peak Value = 1.414 x RMS Value
Peak to Peak Value = 2 x Peak Value
Peak to Peak Value = 2.828 x RMS Value

Acceleration

1 g = 32.174 ft/sec2

1 g = 9.807 m/sec2

in./sec2 = 0.0254 m/sec2

Displacement

1 mil = 0.001 in.

1 mil = 0.0254 mm

1 in. = 25.4 mm

1 cm = 10 mm

Frequency

1 Hz = 1 cps

1 Hz = 0.159 rad/sec

1 Hz = 60 rpm

1 rpm = 0.0167 Hz

1 rpm = 1 cpm

Compliance and Pressure

mm/N = in./lb x 5.7

in./lb = mm/N x 0.175

psi = kg/cm2 x 14.223

kg/cm2 = psi x 0.0703

psi = Pascal (Pa) x 1.45 x 10-4

Pascal = psi x 6895

Pascal = kg/cm2 x 9.8 x 104

Weight

1 oz = 28.35 grams

1 kg = 2.205 lbs

1 N = 0.2245 lbs

Temperature

°C °F
-50 -58
-40 -40
0 32
25 77
80 176
120 248
200 392
260 500
Density
lb/in3 (103kg/m3)
Young’s Modulus
106 psi (GPa)
Shear Modulus
106 psi (GPa)
Thermal Expansion Coefficient
10-6/°F (10-6/°K)
Thermal Conductivity
BTU/hr-ft-°F (W/m-°K)
Specific Heat
BTU/lb=°F
(103 J/kg-°K)
Ferromagnetic Materials
Carbon Steel 0.28 (7.8) 29.0 (200) 11.0 (76) 5.6 (10) 26 (45) 0.11 (0.46)
400-Series Stainless Steel 0.28 (7.8) 29.0 (200) 11.0 (76) 5.6 (10) 14 (24) 0.11 (0.46)
Super Invar at 20°C 0.29 (8.0) 21.5 (148) 8.7 (60) -0.1 (-0.2)
at 50°C approx. 0
6 (10) 0.12 (0.50)
Cast Iron 0.26 (7.2) 15.2 (105) 6.1 (42) 6.0 (11) 28 (48) 0.13 (0.54)
Nonferromagnetic Materials
300-Series Stainless steel 0.29 (8.0) 29.0 (200) 12.5 (86) 9.2 (16.6) 9 (16) 0.12 (0.50)
6061-T6 Aluminum 0.10 (2.8) 9.9 (69) 3.8 (26) 13.0 (23) 96 (166) 0.21 (0.88)
Granite 0.10 (2.8) 7.0 (48) 3.0 (21) 4.0 (7) 2 (3.5) 0.20 (0.84)
Concrete 0.09 (2.5) 3.0 (21) 1.3 (9) 8.0 (14.4) 0.5 (0.9) 0.16 (0.67)