What Is Thin Film Stress?

Thin film stress refers to the stress component uniformly distributed along the thickness of the section, which is equal to the average value of the stress along the thickness of the section under consideration. The shell stresses solved by the momentless theory are all film stresses, and they are primary film stresses. According to the calculation with moment theory, the discontinuous stress also contains the film stress component, but it is a secondary stress. Because the film stress exists in the entire wall thickness, plastic deformation of the entire wall thickness will occur once yielding occurs. In pressure vessels, its hazard is greater than the equivalent bending stress (bending stress is distributed linearly or non-linearly along the wall thickness). ^[1]