Not only can this be done, but it also is done for concrete structures all the time.
The shear reinforcement in concrete beams is calculated using Mörsch's truss analogy model:
The concrete beam is simplified into a truss, where the upper chord (under compression) is the concrete itself, the lower chord (under tension) is the longitudinal reinforcement and the verticals are the shear reinforcement.
Now, to be clear, this model effectively calculates the shear force that must be resisted by the stirrups, not the shear stress. But the concept is the same.
And yes, this is similar to FEA. FEA is basically the creation of a really messy truss (aka, the mesh). You then calculate the deflections of each of the tiny "bars" that compose the mesh, and then some fancy math lets you convert that to stresses within each of the cells.