Converting from lb_f/in to N/m issues

  • Thread starter Thread starter Dustinsfl
  • Start date Start date
  • Tags Tags
    Issues
Click For Summary
SUMMARY

The discussion centers on converting damping parameters from imperial units to metric units for a mechanical system. The user calculated the spring constant (k) as 8756.34 N/m, damping coefficient (c) as 131.345 N/m-sec, and mass (m) as 22.675 kg. The damping ratio (ζ) was computed to be 1000.26, raising concerns about the accuracy of the conversion factors used. The user identified a mistake in their calculations, specifically dividing mass by spring constant instead of the reverse.

PREREQUISITES
  • Understanding of mechanical damping systems
  • Familiarity with unit conversions between imperial and metric systems
  • Knowledge of the damping ratio formula
  • Basic principles of dynamics and oscillatory motion
NEXT STEPS
  • Review unit conversion techniques for mechanical properties
  • Study the definition and calculation of natural frequency (ω_n)
  • Learn about the implications of high damping ratios in mechanical systems
  • Explore the relationship between mass, spring constant, and damping in dynamic systems
USEFUL FOR

Mechanical engineers, physics students, and anyone involved in the analysis of dynamic systems and damping behavior.

Dustinsfl
Messages
2,217
Reaction score
5

Homework Statement


I am trying to find a damping ratio. I know ##k=50## lb##_f##/in, ##m=50## lb, ##c = 0.75## lb##_f##-sec/in.

Homework Equations


##1## lb##_f##/in = ##175.1268## N/m
##1## lb = ##0.4536## kg

The Attempt at a Solution


Then ##k = 8756.34## N/m, ##c = 131.345## N/m-sec, and ##m = 22.675## kg.
$$
\zeta = \frac{c}{2\omega_nm} = \frac{131.345}{2(0.00259)(22.675)} = 1000.26
$$
but this seems awfully large. Are my conversion factors incorrect?
 
Physics news on Phys.org
How is ##\omega_n## defined?
 
vela said:
How is ##\omega_n## defined?

Thanks. I divided m by k instead of the other way around.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 29 ·
Replies
29
Views
23K
  • · Replies 21 ·
Replies
21
Views
5K
Replies
15
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
8
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K