Calculate approximately G-force applied on Car shock absorber

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SUMMARY

The discussion focuses on calculating the G-force applied to car shock absorbers using accelerometers placed on the wheels. Two scenarios are analyzed: one with a car traveling at 110 km/h over a 5 cm bump and another at 50 km/h over a 30 cm speed bump. The user attempts to apply the formula A=5cm and ω=sqrt(k/m) to derive acceleration but encounters abnormally high G-force values. The conversation emphasizes the importance of considering the bump's slope and rise/run ratio in G-force calculations.

PREREQUISITES
  • Understanding of basic physics principles, specifically acceleration and G-force calculations.
  • Familiarity with the dynamics of car suspension systems and shock absorbers.
  • Knowledge of data acquisition techniques using accelerometers.
  • Basic mathematical skills for applying formulas related to oscillation and acceleration.
NEXT STEPS
  • Research "Calculating G-forces in automotive applications" for practical methodologies.
  • Learn about "Accelerometer data analysis techniques" to improve data interpretation.
  • Study "Spring constant determination methods" to accurately model shock absorber behavior.
  • Explore "Vehicle dynamics and suspension tuning" to understand the impact of bumps on G-force.
USEFUL FOR

Automotive engineers, data acquisition specialists, and anyone involved in vehicle dynamics or suspension system analysis will benefit from this discussion.

ELEFANTOMET
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I have to do some dataacquisition from a car with some accelerometers.

4 accelerometers is placed on the wheels before the shock absorber. And i need to calculate the maximum applied G-force on the accelerometers.

Just an approximately value, not taking in account the type of wheel, airpressure in wheel etc.

Scenario 1:
Steady speed of the car driving on normal tarmac is 110km/h.
Weight of car is 2000kg
The car is driving over a small bump with a height of 5cm

Scenario 2:
Steady speed is 50km/h
Weight 2000kg
The car is driving over a regular speedbump, approximately height of 30cm

Seeing the bump on the wheel as if was a regular spring, i would calculate acceleration from
A=5cm
ω=sqrt(k/m) (not knowing the spring constant, i just took some samples from 0-500Hz as a value, what's realistic here?)
a=-ω^2*A*cos(ω*t)
with a.max being -ω^2*A

and then divide final max acceleration with 9.8m/s^2. But this seem to give me abnorm large value of g-force.

Any help, to how to calculate this the right way?
 
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The rise/run ratio of your bumps will have some determination of your G force.
A slightly sloped bump gives less G force than a sharp bump, due to Ft.

A 30 cm bump - this is a regular sped bump height?
 

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