Finite element tensile fracture analysis of α-uranium based on crystal plastic model

As the most stable structural form of uranium crystals, α-uranium exhibits a profound influence in multiple fields such as the nuclear industry, materials science, and medicine. its complex plastic deformation mechanism poses numerous challenges to the design and service in practical engineering. In order to deeply explore its mechanical properties and deformation mechanism, numerous researchers have conducted tensile tests on α-uranium. Nevertheless, its numerical model still needs further development. By combining the user defined subroutine Umat and the user defined element Uel, a tensile simulation of α-uranium is carried out based on the crystal plasticity model and the cohesive element, and the influence of the geometric morphology of defects on its mechanical properties is deeply discussed. Using the accumulated plastic strain contour, the accumulation process of plastic strain during the crack initiation and propagation is systematically analyzed. On this basis, defects with different geometric shapes are introduced. the defect morphology and angle are quantitatively characterized. The results show that the crystal plasticity model can effectively simulate the tensile and fracture behavior of α-uranium. When there are defects in the material, the cracks mainly concentrate on the local geometry perpendicular to the loading direction, and stress concentration occurs near the sharp corners, which in turn triggers the initiation and propagation of cracks, ultimately reducing the strength and toughness of the material.