User:Eml4500.f08.ramrod.c/9-29-08

2 Bar Truss System


Closing the loop refers to the two upward pointing arrows on the right side of the figure, making your way back to computing the reaction forces.

Using Statics
Taking a look back at the statics method, the reaction forces known and unknown therefore the member forces are P1(1), P2(2)
 * Note: Both members are in tension

How to Compute the axial displacement of dofs (degrees of freedom) or the amount of extension of the bars:
$$ q_2^{(1)} = \frac {P_1^{(1)}}{d^(1)} = \frac {P_2^{(1)}}{k^{(1)}} = AC $$
 * P1(1) = P2(1)
 * q1(1) = 0, Fixed global node 1

$$ q_1^{(2)} = \frac {-P_2^{(2)}}{k^{(2)}} = -AB $$


 * q2(2) = 0, Fixed global node 3