# Spring force formula

This topic is 5218 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

Hi guys L - spring vector l - length of the spring (scalar) ks - spring constant kd - damping constant v1,v2 - velocities of spring's ends r - rest length of the spring May I know what is the correct formula to calculate spring force between 2 points? Is it this : f1 = {ks(l-r) + kd[(v1-v2)*L]/l}*L/l f2 = -f1 or f1 = -{ks(l-r) + kd[(v1-v2)*L]/l}*L/l f2 = -f1 Thanks.

##### Share on other sites
I just keep running into you [8^)

first, I'm going to call L/l => L^ (unit length vector)

OK, break this into two parts:

Components:
Fspring = ks * (l - r)
Fdamping = kd * [(v2 - v1) dotproduct L^]

final version:
Ftotal = L^ * (Fspring - Fdamping)

yopu may need to play with the signs, depending on which direction L is calculated; (p2 - p1) or (p1 - p2).

##### Share on other sites
Thanks for your help again. The reason why I am confused is that I saw somewhere here the correct formula posted here is the first version whereas the version I got on the paper I am reading is the 2nd one.

I suspect the formula found here -> http://www.dcs.uky.edu/~seales/dli2/iccv-final-01.pdf under section 3.2.1 is wrong. Hope you can verify it. Thanks.

Quote:
 Original post by lonesockI just keep running into you [8^)first, I'm going to call L/l => L^ (unit length vector)OK, break this into two parts:Components:Fspring = ks * (l - r)Fdamping = kd * [(v2 - v1) dotproduct L^]final version:Ftotal = L^ * (Fspring - Fdamping)yopu may need to play with the signs, depending on which direction L is calculated; (p2 - p1) or (p1 - p2).

1. 1
2. 2
3. 3
Rutin
15
4. 4
5. 5

• 9
• 9
• 9
• 11
• 11
• ### Forum Statistics

• Total Topics
633679
• Total Posts
3013299
×