Hi, in COMSOL Multiphysics, "Solid Mechanics" physic, how can I define a boundary load which is applied to a simple beam and it is varying with the beam's displacement (w) ? For example assume a simple load like : f=(w^1/2)
Hi,
You can SOLVE your model in PDE MODULE of comsol. Your's equation of beam will be in 4th derivative.you cannot use directly a 4th derivative of a dependent variable. COMSOL is only set up for 2nd derivatives "uxx" you must create a new dependent variable defind as the 2nd derivative, ensure you use 2nd order discretization or more (the default) and then couple in this equation.
Hi Mahdi,
In Component -> Definitions you can define a variable e.g. beam_disp = w on the specific boundary. Then you can use that variable in your equation (also defined as variable) f = (beam_disp^1/2) and assign that to you boundary.
I used this to calculate the electrostatic pull in voltage of cantilever beams. You might also have to pay attention to instability points when the applied load is increasing strongly with increase in displacement.
Hi Deepak and René,
Thank you very much for your helpful respond. I've been working on a microbeam's dynamic pull in with a load applying simultaneously. I defined a load expression as a variable which was wrong, and now i found the answer and it works!
Thank you so much again
Hi Mahdi,
I am working on a moving body using force applied can u explain what u did
TIA
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