Optimal Design of a Miniaturized Cruciform Specimen for Biaxial Testing of TA2 Alloys

The biaxial tensile testing of cruciform specimens is an effective way to create complex loading, and is a feasible experimental method for studying the subsequent yield behavior. However, relevant knowledge gaps still exist in the geometric design of miniaturized cruciform specimens which are applicable to test machines with maximum load less than 5000 N. The present work outlines the systematic investigations of the optimal design of the miniaturized cruciform specimen of a commercial pure titanium TA2 for biaxial tensile testing. Finite element modeling (FEM) coupled with the orthogonal design is employed to explore the influence of various geometric parameters, i.e., the thickness of the central gauge region, the width, the length, and the number of the slit, and the radius of the inner chamfer, on the stress distribution of the central gauge region. The optimal geometric design of the miniaturized cruciform specimen is successfully obtained, simultaneously considering the stress uniformity in the central gauge region and economic factors. The full-field strain distributions are also determined via the digital image correction (DIC) technique, which confirm the accuracy of the results achieved from FEM. This work provides a complete and reliable procedure for optimizing the geometry of miniaturized cruciform specimens, whose application can be expanded to other metals in the future.