Is the Hertzian Contact Model Suitable for Simulating Car Braking on Wet Roads?

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The discussion revolves around the suitability of the Hertzian contact model for simulating car braking on wet roads. A French student is seeking a realistic tire model to analyze how water affects emergency braking distances, expressing skepticism about the Hertzian model due to its assumption of no friction. The student’s physics teacher recommended this model, but the student is considering the JKR model, which includes friction. Suggestions include consulting published research on braking distances and driver behavior to enhance the project. The conversation emphasizes the need for a model that accurately reflects real-world conditions for effective simulation.
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Homework Statement
How does the presence of water on the road influence the emergency braking distance of a car?
Relevant Equations
-
Hi there!
First of all, I do not have a clear homework statement or relevant equations to give but I still put this thread in here because it's related to school work and I've previously got a warning for not doing so.

I'm a french student who is going to start his second year after high school in september.
At the end of the year, I will have competitive exams to get into an engineering school.
For this exam, I have some research to present. I work on "How does the presence of water on the road influence the emergency braking distance of a car?".
I would like to have a preferably simple but rather realistic physical model of a tire to simulate a car braking with and without water on the road surface.

My physics teacher told me that with a "solid, undeformable" tire model like I use to do in this thread, I will be way too far from reality and told me to try the Hertzian model, which he told me was quite simple.
Problem is, that the very first hypothesis of the model is that there is only a normal force, thus no friction. This makes me quite skeptical about the relevance of this model. Moreover, after two weeks of research, I haven't seen anyone using it in the context of a moving vehicle.

So do you think this model may fit my needs? Or what other model could I take a look at?
I'm thinking about the JKR model, which seems to be very close to the one of Hertz, but admits friction.
 
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ROOT0X57B said:
Homework Statement:: How does the presence of water on the road influence the emergency braking distance of a car?
Relevant Equations:: -

Hi there!
First of all, I do not have a clear homework statement or relevant equations to give but I still put this thread in here because it's related to school work and I've previously got a warning for not doing so.

I'm a french student who is going to start his second year after high school in september.
At the end of the year, I will have competitive exams to get into an engineering school.
For this exam, I have some research to present. I work on "How does the presence of water on the road influence the emergency braking distance of a car?".
I would like to have a preferably simple but rather realistic physical model of a tire to simulate a car braking with and without water on the road surface.

My physics teacher told me that with a "solid, undeformable" tire model like I use to do in this thread, I will be way too far from reality and told me to try the Hertzian model, which he told me was quite simple.
Problem is, that the very first hypothesis of the model is that there is only a normal force, thus no friction. This makes me quite skeptical about the relevance of this model. Moreover, after two weeks of research, I haven't seen anyone using it in the context of a moving vehicle.

So do you think this model may fit my needs? Or what other model could I take a look at?
I'm thinking about the JKR model, which seems to be very close to the one of Hertz, but admits friction.
The first thing to do is take what you have learned so far to the teacher and ask if he would change his recommendation based on your information.
 
Sure, but it's vacation time and I don't have any way to join him, that's why I'm asking here actually.

Note : we haven't seen anything about the physics of deformable materials and surfaces.
 
ROOT0X57B said:
Sure, but it's vacation time and I don't have any way to join him, that's why I'm asking here actually.

Note : we haven't seen anything about the physics of deformable materials and surfaces.
I suggest researching the problem looking for published papers dealing with the topic and then apply the appropriate level of detail for your project.

Here are a couple of places to start; https://www.researchgate.net/publication/242572582_DETERMINATION_OF_BRAKING_DISTANCE_AND_DRIVER_BEHAVIOUR_BASED_ON_BRAKING_TRIALS

https://www.trafitec.dk/sites/default/files/publications/braking distance - friction and driver behaviour.pdf
 
What does the term "Hertzian contact" mean?

NVM, I now read the whole message and saw the link...
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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