Truss Withstand Shear Force, Not Transfer Bending Moment
The truss structure is a structural frame based on the geometrical stability of the triangle, which consists of a linear rod which is only subjected to axial tension or axial pressure, and the linear force of the node transmits the rod, bears the shearing force, and does not transfer the moment. The linear rods of the truss structure can be hinged or just connected.
Some students asked, whether the node of the truss is hinged or just connect well.
A real truss structure, in the bearing of the external load, must function at the node, the load will be the whole bar by the simple compression or simply pull the way, the node only transfer the linear force of the rod, bear shear force, not to pass the moment. In this case, the linear bar can be articulated between the two, can also just connect, completely depending on the construction convenience and appearance of the shape, in the Force no difference, do not need to be particularly strengthened node.
A truss structure is generally not applied to a linear bar. When the load is exerted on the bar, if the joint is hinged, only the loaded member is subjected to the bending moment in the form of simply supported beam, and the rest of the rods are not involved in the load. As a result, the bending rod must be strengthened, while the other rods are purely superfluous. If the node is just connected, each bar will be formed in the form of the frame of the whole bending, not only the rod itself, even its nodes will bear very large bending moment, need to be strengthened.