Simulating Beam Stress in a Bridge-Simulation Game

  • Thread starter franticfantom
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In summary, the individual is seeking guidance on how to best simulate a bridge in a game using Box2D. They are currently using reaction forces of beam pins to determine stress, but this method has limitations. They want to see beams visually break and distinguish between compression and tension. They are considering using reaction torque, but unsure how it would help. They have attempted to calculate stress using a formula involving the dot product, but are unsure if it is correct. They also mention that the bridge structure is made up of trusses connected by pins.
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franticfantom
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I'm making a bridge-simulation game. I'm using Box2D for the physics engine. I'm trying to figure out the best way to get the amount of stress on a beam. Right now, I'm taking the reaction force of the pins of the beam (Which is FA and FB in the attached diagram below) and comparing them to a maximum value.
There are 2 problems with this:
  1. The bridge only breaks apart at the pins
  2. There is no distinction between compression and tension.
So, I need to rethink how to simulate the bridge. I want to be able to see the beams themselves break in half (or even wherever it should break, that'd be cool), and a visualization of both tension and compression for the beams. For a specific beam, I can get the reaction force (FA and FB) of each of its pins (A and B). I can get the position of each side of the beam (A and B, which are also the position of each pin). I can also get the reaction torque of each beam (though I'm not sure how that'd help me).
Here's my attempt at finding the stress on a beam: (sorry I can't figure out how to work latex)

SAB=(FA * AB) + (FB * BA)​

Where AB or BA is the beam (and the vector that represents it), SAB is the stress of AB, * is the dot product, and FA, FB is the reaction force of A and B, respectively.

Is this correct? If not, can someone guide me in the right direction?
 

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Thanks! Edit: I should also note that the bridge structure is made up of trusses, which are made up of beams connected at pins. (See diagram).
 

1. What is the definition of stress in a beam?

Stress in a beam is the measure of the internal force that a beam experiences when subjected to an external load. It is typically measured in units of force per unit area.

2. How do you calculate the stress of a beam?

To calculate the stress of a beam, you need to know the applied load, the cross-sectional area of the beam, and the moment of inertia. The formula for stress in a beam is stress = (applied load * distance from neutral axis) / moment of inertia.

3. What factors can affect the stress of a beam?

The stress of a beam can be affected by the type and magnitude of the load applied, the material properties of the beam (such as strength and elasticity), the geometry of the beam (such as length and cross-sectional shape), and the support conditions.

4. Why is it important to find the stress of a beam?

Finding the stress of a beam is important for ensuring the structural integrity and safety of a beam under load. It allows engineers to determine the maximum load a beam can withstand without experiencing failure or excessive deformation.

5. Can the stress of a beam be reduced?

Yes, the stress of a beam can be reduced by increasing the beam's cross-sectional area, using a stronger and more rigid material, or by redistributing the load in a more efficient way. Proper design and engineering can also help reduce the stress on a beam.

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