Updated model for lateral displacement of nonuniform webs

The theory for lateral mechanics of nonuniform webs in the open literature is believed to be flawed and an updated theory is presented. The theory is based on beam theory and a set of boundary conditions. The so-called fourth boundary condition is discussed and a condition is chosen based on the argumentation. A new term in the governing differential equations is derived. The updated theory predicts that the web moves to the slack side if there is sticking friction between web and roller