How to define physical (material) point in simmechanics or other tool ?

In model I constructing with use of SIMMECHANICS there is no meaning for inertia or shape of rigid bodies. Only motion properties make sense. I know that rigid body's big quantity makes to the model run slowly.

Is it possible force the model run more quickly by defining material/physical point block or system?

Answer 1

[Arnaud Miege]

The key parameters for a SimMechanics Body block are its mass and inertia tensor relative to the centre of gravity of the body. These are obviously dependent on the shape and material properties of the body, but you need to compute the mass and inertia tensor outside of SimMechanics. I have seen examples where people create their own libraries with various templates (e.g. cylinder, sphere, etc...), which are essentially a masked subsystem with a Body block underneath it. The user enter the geometric dimensions and the material of the shape in question, and the mass and inertia calculations are done in the mask initialization.

Once you have defined the mass and inertia tensor, you can then add points (CS) to the Body to connect it to other bodies or parts of the system, and also improve the visualization.

There are various examples on the File Exchange, I suggest you have a look.

The alternative is to define you mechanical system in a supported CAD package and then use SimMechanics Link to generate the model.

HTH,

Arnaud

[Alexander Brodsky]

Thanks for answer, I would like make some explanations.

In my model more than 200 rigid bodies (dynamic number), extracted by script from matlab file. My purpose to check 3D orientation of the model in every moment. The model changes it's position by motion actuator and not depends on forces. So I interested if it possible to declare "mass less" material point.

The model is like fishnet, when intersections (knots) defined in the model as rigid body and lines between knots defined as spherical-spherical massless joint.

[HITESH TRIVEDI]

Hi

I m also trying to find a way to calculate force on body at any point when a force is given to that body's end. the other side of body is hinged. The reaction force can be used for finding out force at hinge or joint...but i m not able to correlate same with the force at the desired point. How to find out?

Hitesh