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Force and torque change with conditions
Posted 12 set 2025, 09:51 GMT-4 Structural & Acoustics, Modeling Tools & Definitions, Structural Dynamics Version 6.3 2 Replies
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One type of simulation (multibody dynamics) I want to achieve is to apply a certain external force and torque on an object, with the requirement that the magnitude of the applied external force and torque changes continuously with displacement. It should be such that the magnitude of the force and torque is just enough to cause displacement. How should I set this up?
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Hi,
sounds like an optimization Problem. 1st I would measure the displacement w. 2nd vary the force and torque until your displacement starts to change.
The variation you can do via a parameter sweep with fixed steps or,
use parameter optimization of an optimization study.
BR Sven
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If the force and torque have a fixed relation, it is not that problematic. If not, there could be an infinite number of combinations that give the intended displacement.
But if we assume the easy case, then you can add a multiplier, say 'p', in front of both the loads. The, you add a Global Equation where you solve for 'p'. The equation should be something like
aveop1(u)-u_wanted
Here, aveop1 is an average operator, measuring the displacement in a point. A probe would work too for the same purpose.
-------------------Henrik Sönnerlind
COMSOL
