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Lumped mechanical module

Posted 28 oct. 2024, 10:16 UTC−4 0 Replies

Filippo Tosato

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i want to couple a structure and discrete spring-mass system representing a local resonator defined as: displacement node at the connecting point (where input displacement is computed from multicoupling), a spring, a mass with free end node in lumped mechanical module. my structure is a hollow cylinder excited at the top. in lumped-structure connection i define the direction of the discrete system which it depend on the position along the circumference. when i solve in frequency domain i do not get any difference with/without the presence of discrete system or i got a problem in the segregated solver.
I have tried a 2d simple case and was working fine but when i move to 3d case it seems there is no coupling between the systems. I thought i should add the reaction force of the displacement node as a point load in solid mechanics (-lms.disp1_f) but still no way. I thought maybe i should use external source instead of displacement node but two port are required and each resonator is only connected to one point.

i have tried a different approach using PDE :add global equation, call a function as x, add weak contribution where mass(2pifreq)^2x*test(x) is my cinetic energy of the resonator and add spring-damper with source point defined as connection point and for destination point i prescribed the displacement as x. It works if i'm considering only one direction in the x,y,z which is 1,0,0. the problem arises when the resonator is placed along the circumference (for example theta angle ) of the cylinder where i have to add the x,y contribution but it doesn t work anymore. if you have any suggestion using the first one or the second method please let me know

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