Experimental Procedures and Results for Benchmark 3: Stage 2 Forming Process

The Numisheet 2005 Benchmark ♯3 consists of a two stage forming process performed on four materials (three steels and one aluminum). Stage 1 consists of forming channel sections in a channel draw die with variable penetration draw beads, and is described in detail in another report. In Stage 2, described here, the samples from Stage 1 are trimmed and subjected to near plane strain Marciniak style cup test. The plane straining is performed in 0 ° and 90 ° orientations. After failure limits for the cup depths are determined, trimmed samples from Stage 1 are strained to specific cup depths (less than the depth of failure) and stresses are measured in situ using a unique X‐ray diffraction technique. The results are repeatable and consistent with expectations. The goal of this benchmark is to check not only the strain achieved during a two stage forming process, but also to develop data that include the stresses achieved. These results may then be used to further test the ability of numerical models to predict...