Determining spring constant of a tire

[thijsdb]

Homework Statement

We are modeling the behavior of a sack truck when driven over a small step. Afterwords we will do some tests with an actual sack truck to verify the model. The movement will be modeled simply like a spring-damping system only having one spring and one damper, thereby ignoring horizontal movement. The occurence of the step will be modeled as a step-function: the ground will move upwards 2 cm for just .02 seconds.

mass of truck
mass of load
angles
measurements of truck
tire measurements
tire pressure
NEEDED: spring and damping coefficient

Homework Equations

How can we calculate, or reasonably estimate the spring and damping constant of the tire, given its measurements and pressure?

The Attempt at a Solution

First I thought about the surface touching the ground, given the pressure a force can be obtained by deviding the pressure by the area. This force then corresponds to a vertical position of the tire. Several measurements will give us different forces and different lengths, making the calculation of the spring constant possible. However this would involve measuring the pressure at each different position, as well as surface and position itself. this is very difficult since compressing the tire requires a lot of force and is only moves about .05 cm.. making acurate measurements difficult.
>Therefore we would like to know a way to calculate it or estimate the values, given the measurements & pressure

 

[KataKoniK]

.

I understand the importance of accurately modeling and testing the behavior of a sack truck over a small step. In order to determine the spring and damping coefficient of the tire, there are a few factors that need to be taken into consideration.

Firstly, the mass of the truck and load will affect the overall movement of the truck when driven over a step. This can be calculated using the equation F=ma, where F is the force, m is the mass, and a is the acceleration.

Next, the angles of the truck and the step will also play a role in the movement and force exerted on the tire. These angles can be measured using a protractor or other measuring tools.

In terms of the tire itself, the measurements of the truck and tire, as well as the tire pressure, will be important in determining the spring and damping coefficient. As mentioned in the post, the surface touching the ground will experience a force due to the pressure and area of contact. This can be calculated using the equation P=F/A, where P is the pressure, F is the force, and A is the area of contact.

To accurately estimate the spring and damping coefficient, it may be helpful to gather data from multiple trials of driving the truck over the step at different speeds and angles. This will allow for a range of forces and movements to be observed and analyzed.

Another approach could be to use computer simulations to model the behavior of the truck and tire, and then compare the results to the actual tests with the truck. This could help to fine-tune the estimated values for the spring and damping coefficient.

In conclusion, accurately determining the spring and damping coefficient of the tire will involve considering various factors such as mass, angles, measurements, and pressure. It may require multiple trials and approaches to accurately estimate these values, but it is important to strive for accuracy in order to ensure the validity of the model and its application to real-world situations.