I am establishing a MatLab FEA code for determining the stiffness of a structure. Diagram of the structure is added below. I have established a code for determining the stiffness of the structure, but I am unsure of how to treat node B. Element AC is one continuous beam with element BD connected to it through a pin connection. That is, element BD will only experience axial forces (= no angular displace), while element AC at node B will experience axial forces AND bending moment, causing angular displacement. So how do I treat this node? I can not say angular displacement is 0, because it is not for element AC. But if I say it is different from zero, the connection will act as if it was welded together.
Please let me know if you need more information.