In this chapter, sheet-metal formability tests, such as the tensile test, the plane-strain test, and the in-plane stretching test are analyzed. The FEM and experimental methods were used in order to demonstrate how two-dimensional in-plane simulation can help interpret and develop such tests, as well as to understand the nature of material behavior and governing mechanics.

A successful sheet-metal forming process can convert an initially flat sheet into a useful part of the desired shape. The major failures that may be encountered are splitting, wrinkling, and shape distortion. The deformed part can be considered unusable if any one of these failures occurs. Formability tests may be used to assess the capacity of a sheet to be deformed into a useful part.

Since sheet-metal forming operations are diverse in type, extent, and rate, many formability tests have been proposed. No single one can provide an accurate indication of the formability for all situations. Formability tests can be divided into two types: intrinsic and simulative. The intrinsic tests measure the basic material properties under certain stress—strain states, for example, the uniaxial tensile test and the plane-strain tensile test. Simulative tests subject the material to deformation that closely resembles a particular press-forming operation. A simulative test can provide limited and specific information that may be sensitive to factors other than the material properties, such as the thickness, surface condition, lubrication, and geometry and type of tooling.