Virtual Work - One Degree-of-freedom Mechanisms

One Degree-of-freedom Mechanisms

In this section, the principle of virtual work is used for the static analysis of one degree-of-freedom mechanical devices. Specifically, we analyze the lever, a pulley system, a gear train, and a four-bar linkage. Each of these devices moves in the plane, therefore a force F=(f_x, f_y) has two components and acts on a point with coordinates r= (r_x, r_y) and velocity v=(v_x, v_y). A moment, also called a torque, T acting on a body that moves in the plane has one component as does the angular velocity ω of the body.

Assume the bodies in the mechanism are rigid and the joints are ideal so that the only change in virtual work is associated with the movement of the input and output forces and torques.