Hi Mr. KJELBERG,
I did and I'm still doing some work with comsol for my master degree first and right now for my PhD, all concerning the nonlinear modeling of bridges (suspensions bridges and arch bridges) and the analisys of their response under wind loads. I'm trying to implement just an aeroelastic time depending force in the equation of motion of the bridge.
The contest in comsol is PDE mode, general form, in 1D space dimension, let u(x,t) be one of the independent variables and f(t) a known function of my problem. What I want to implement in the F term of the field equation ea*du^2/dt^2+da*du/dt+div(G)=F is
F= int_0^t[(du(x,s)/ds)f(t-s)]ds where "s" is an auxiliary time variable
so a convolutional integral.
I was thinking to bypass this problem by introducing a costraint equation which solution of is just that integral. I'm not sure if I could use the Global equation tool or i better define a new independent variable and set the constraint by the new generated field equation (I used this trick other times). I've not tryed yet this idea...for sure I'm gonna do it on monday when back at work at my University.
I know me too that I can use the dest() operator but just for space integral....and I also read that exist the at() operator but it works just on postprocessing mode.....I was also thinking to split the time analisys and restart it evaluating the convolution integral with this command and updating the equations....and for that reason i thought to use comsol script....
I will work on that!!!
However thank you for the answer
best regards
Andrea
I did and I'm still doing some work with comsol for my master degree first and right now for my PhD, all concerning the nonlinear modeling of bridges (suspensions bridges and arch bridges) and the analisys of their response under wind loads. I'm trying to implement just an aeroelastic time depending force in the equation of motion of the bridge.
The contest in comsol is PDE mode, general form, in 1D space dimension, let u(x,t) be one of the independent variables and f(t) a known function of my problem. What I want to implement in the F term of the field equation ea*du^2/dt^2+da*du/dt+div(G)=F is
F= int_0^t[(du(x,s)/ds)f(t-s)]ds where "s" is an auxiliary time variable
so a convolutional integral.
I was thinking to bypass this problem by introducing a costraint equation which solution of is just that integral. I'm not sure if I could use the Global equation tool or i better define a new independent variable and set the constraint by the new generated field equation (I used this trick other times). I've not tryed yet this idea...for sure I'm gonna do it on monday when back at work at my University.
I know me too that I can use the dest() operator but just for space integral....and I also read that exist the at() operator but it works just on postprocessing mode.....I was also thinking to split the time analisys and restart it evaluating the convolution integral with this command and updating the equations....and for that reason i thought to use comsol script....
I will work on that!!!
However thank you for the answer
best regards
Andrea
