Thanks for the response , i'm going to answer all the above :
1) Supports are fixed , the bars can only rotate .
2)I dont have numerical values of the data , i try to solve it using variables and create a general formula
3)Yes , the connecting joint has an initial displacement . I dont have any other data about magnitude or direction , i only know that i have displaced the connecting joint and later i let it move freely ( from zero velocity) and an oscillation takes place ( on x , y axis) due to elasticity .
4)If "U" is the horizontal velocity and "V" the vertical velocity of the connecting joint then i want to find how these 2 velocities change during the oscillation/time . I want to find the formulas for U(t),V(t) (t=time) . But yes oscillation frequency is needed for these equations .
5)I consider only axial deformation , and the maximun degrees of freedom for each node should be 2 ( moving vertically , moving horizontally)