G Force Calculation Optimisation with camera, equations & accelerometer (drop testing)

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In summary, the document discusses an optimization method for calculating G-force during drop testing using a combination of camera footage, mathematical equations, and accelerometer data. It emphasizes the integration of these tools to enhance the accuracy of G-force measurements, allowing for better analysis of the impact forces experienced by objects during free fall. The approach aims to improve the reliability of testing results in various applications, such as product safety and material durability assessments.
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TL;DR Summary
G Force Calculation Optimisation with camera&equations&accelerometer
Hello, we do drop testing on devices and we have an accelerometer. Our accelerometer does not always give accurate G values, that is, as the altitude increases, the G force should increase, but there are moments when it decreases. We also place impact labels on the box we throw away, but they cannot always verify this situation.

I'm trying to get more accurate results on the computer with the help of a camera. Peak accelerations average 441 in all tests (427-528). I tried to find a better result by dividing these by the collision time, and indeed I got slightly better results, but I'm never sure.

Apart from this verification, I also want to reach this result by making calculations. I don't know how the G-Force value is calculated, it is calculated differently in many sources. Maybe I'm wrong because I examined the calculations according to the impact label table.

To give an example, we carry out the tests by raising the height by 10 centimeters:

385G in 30cm
40 542G
50 550G
60 552G
70 524??
80 425??

We reach the values and the impact label of the device turns red at 80 cm, but the G value is lower than other heights.

I also want to develop a simulation. With which application can I find an easier and faster result while developing this simulation? I'm waiting for your help.
 
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Welcome to PF.

Can you upload some pictures of your test setup and sample preparation? (Use the "Attach files" link at the lower left of the Edit window.) It looks like you have some extra friction or binding in the higher drop tests...
 
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  • #3
ao01 said:
I tried to find a better result by dividing these by the collision time,
You should rather intergrate the acceleration over time, and compare that to the expected velocity change.

ao01 said:
To give an example, we carry out the tests by raising the height by 10 centimeters:
Did you drop it from each height several times? What is the spread of values you get for a fixed height?

What is the temporal resolution of your accelerometer and data recording? Are you sure it can even capture short time peaks properly?
 
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berkeman said:
Welcome to PF.

Can you upload some pictures of your test setup and sample preparation? (Use the "Attach files" link at the lower left of the Edit window.) It looks like you have some extra friction or binding in the higher drop tests...
I'm sorry, I'm on leave for a while, but the system is like this. I am using pcc program with determine the speed and acceleration. If it might be useful to you, I can share the velocity and acceleration txt documents, but I don't think you can understand them alone.

1722252339286.png
1722237839007.png


A.T. said:
You should rather intergrate the acceleration over time, and compare that to the expected velocity change.


Did you drop it from each height several times? What is the spread of values you get for a fixed height?

What is the temporal resolution of your accelerometer and data recording? Are you sure it can even capture short time peaks properly?
We could only do it once because we did not have enough impact labels.
 
  • #5
ao01 said:
We could only do it once because we did not have enough impact labels.
I'm asking about your accelerometer values. How consistent are they for the same drop height?
 
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FAQ: G Force Calculation Optimisation with camera, equations & accelerometer (drop testing)

What is G-force and how is it calculated?

G-force, or gravitational force, is a measurement of acceleration felt as weight. It is calculated using the formula: G = a / g, where 'a' is the acceleration experienced by the object (in meters per second squared) and 'g' is the acceleration due to gravity (approximately 9.81 m/s²). A G-force of 1G is equivalent to the force of gravity acting on the object.

How can a camera be used for G-force calculations?

A high-speed camera can be used to capture the motion of an object during a drop test. By analyzing the video frame by frame, the velocity and displacement of the object can be determined. From this data, acceleration can be calculated, which can then be used to find the G-force experienced by the object during the drop.

What role does an accelerometer play in G-force measurement?

An accelerometer is a device that measures the acceleration of an object in real-time. In drop testing, an accelerometer can be attached to the object to directly measure the forces acting upon it. The data collected from the accelerometer can provide accurate readings of G-forces during the drop, allowing for precise analysis of the impact forces experienced.

What equations are commonly used in G-force calculations during drop tests?

Common equations used include Newton's second law (F = ma), where F is the force, m is the mass of the object, and a is the acceleration. Additionally, the kinematic equations, such as v² = u² + 2as, can be used to relate initial velocity (u), final velocity (v), acceleration (a), and displacement (s) during the drop to calculate G-forces.

What are the challenges in optimizing G-force calculations during drop testing?

Challenges include ensuring accurate calibration of measurement devices, minimizing environmental factors that can affect readings (like air resistance), and handling data noise from sensors. Additionally, synchronizing data from cameras and accelerometers can be complex, requiring precise timing and data processing techniques to ensure accurate G-force calculations.

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