Question about the effect of acceleration on the force of a mass

Click For Summary

Discussion Overview

The discussion revolves around calculating the additional force exerted on a beam by a mass subjected to acceleration, specifically in the context of vibrations experienced by machinery. Participants explore the implications of acceleration on force calculations, particularly in relation to finite element analysis (FEA) for design purposes.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant queries how to calculate the extra force on a beam due to a mass experiencing a downward acceleration of 2m/s², suggesting a straightforward approach of summing the stationary force and the force due to acceleration.
  • Another participant clarifies that constant acceleration differs from vibration and notes that the calculation may become more complex if the system is not rigid and incompressible.
  • A further contribution provides context about the mass being on a fabricated bracket attached to moving machinery, indicating that the peak acceleration is treated as a worst-case scenario for FEA analysis.
  • One participant states that if the acceleration is measured directly at the object, the force can be calculated simply using F=m*a.
  • Another participant questions whether the acceleration is relative to free fall or rest and suggests considering the maximum upward acceleration for force determination.
  • A participant mentions limitations in their measurement equipment, indicating that they are awaiting access to better tools for more accurate data.

Areas of Agreement / Disagreement

Participants express varying views on the complexity of the calculations involved, with some agreeing on the basic formula while others highlight potential complications due to system rigidity and measurement conditions. The discussion remains unresolved regarding the best approach to take given the specific circumstances.

Contextual Notes

There are limitations related to the assumptions about system rigidity and the nature of the acceleration (whether it is relative to free fall or rest). Additionally, the accuracy of the measurements is contingent upon the equipment used.

diggedy
Messages
4
Reaction score
0
Ive got a query which I am thinking should be simple but I can't for the life of me think how to solve it.

I have a mass of 500 kg resting on a beam. It is subjected to vibration of 2m/s2 directly down, how would I calculate the extra force subjected on the beam due to this acceleration?

Is it as simple as working out the force of the mass while stationary then working out the force applied due to acceleration (m*a) and then adding them together?
 
Physics news on Phys.org
A constant acceleration is not a vibration. For the momentary force: if all parts of the system are completely rigid and incompressible, then it is as simple as you described. Otherwise it gets more complicated.
 
Cheers for the reply. I've probably been a bit vague in the question so ill give a bit more info.

Its a mass on a fabricated bracket attached a moving piece of machinery. I am treating it as a simple steel beam to avoid over complicating it. As the machine moves along the ground, imperfections in the surface cause the mass to bounce. 2m/s2 is the peak acceleration so I was just taking this as a worst case scenario. All I am wanting to do is determine the maximum force this mass exerts on the beam so I can use it for FEA analysis on the beam and use it to design a new bracket as the current one is failing.
 
If you measured the acceleration directly at the object, the corresponding force is just F=m*a.
 
Thanks, I guess I am just over thinking it :)
 
diggedy said:
It is subjected to vibration of 2m/s2 directly down,
Is this acceleration relative to free fall or relative to rest?
diggedy said:
All I am wanting to do is determine the maximum force this mass exerts on the beam
If the mass sits on the the beam, you should look for the maximal upwards acceleration.
 
The accelerometer i had access to didnt give me both direction, only the maximum vibration along that axis. I am getting access to some better equipment next week which may give me better info. I was treating the peak as the maximum either way and its relative to rest
 

Similar threads

High School Effect of mass on the acceleration of an elastic pendulum?
  • · Replies 3 ·
Replies
3
Views
808
High School How Does Constant Power Affect Rocket Acceleration in Space?
  • · Replies 13 ·
Replies
13
Views
935
Undergrad Express drag force/acceleration/velocity as function of time
  • · Replies 14 ·
Replies
14
Views
2K
High School The Effect of Linear and Rotational Motion on Measured Weight
  • · Replies 10 ·
Replies
10
Views
1K
High School Zero acceleration = zero net force?
  • · Replies 33 ·
2
Replies
33
Views
3K
High School Torsion Involving an Off Axis Thrust
  • · Replies 66 ·
3
Replies
66
Views
6K
High School How will object's velocity change when a frictional force increases?
  • · Replies 16 ·
Replies
16
Views
2K
High School Does acceleration affect impact energy vs constant velocity?
  • · Replies 46 ·
2
Replies
46
Views
4K
High School Confused about force body diagram for 2 body collision
  • · Replies 6 ·
Replies
6
Views
2K
High School How to determine applied force when two objects collide? (basic physics engine)
  • · Replies 9 ·
Replies
9
Views
2K