Exact analytic solutions for an elliptic hole with asymmetric collinear cracks in a one-dimensional hexagonal quasi-crystal

Using the complex variable function method and the technique of conformal mapping, the anti-plane shear problem of an elliptic hole with asymmetric colfinear cracks in a one-dimensional hexagonal quasi-crystal is solved, and the exact analytic solutions of the stress intensity factors （SIFs） for mode Ⅲ problem are obtained. Under the limiting conditions, the present results reduce to the Griffith crack and many new results obtained as well, such as the circular hole with asymmetric collinear cracks, the elliptic hole with a straight crack, the mode T crack, the cross crack and so on. As far as the phonon field is concerned, these results, which play an important role in many practical and theoretical applications, are shown to be in good agreement with the classical results.

Dynamic propagation problems concerning surfaces of asymmetrical mode III crack subjected to moving loads

With the theory of complex functions, dynamic propagation problems concerning surfaces of asymmetrical mode Ⅲ crack subjected to moving loads are investigated. General representations of analytical solutions are obtained with self-similar functions. The problems can be easily converted into Riemann-Hilbert problems using this technique. Analytical solutions to stress, displacement and dynamic stress intensity factor under constant and unit-step moving loads on the surfaces of asymmetrical extension crack, respectively, are obtained. By applying these solutions, together with the superposition principle, solutions of discretionarily intricate problems can be found.

In-situ observation of asymmetrical deformation around inclusion in a heterogeneous additively manufactured 316L stainless steel

Oxide inclusions widely exist in additively manufactured components due to the native oxide layer on the powder surface,together with gas impurities during the printing process.Using in-situ tensile tests combined with electron backscatter diffraction(EBSD)and electron channeling contrast imaging(ECCI)techniques,we propose an asymmetrical cracking mechanism around the oxide inclusions in a selective laser melted 316L stainless steel.The heterogeneous sub-micro cellular structures lead to different twinning tendencies around the inclusions due to the size-related critical twinning stresses,and the deformation-induced nano-twin clusters can resist the cracking propagation,therefore resulting in the asymmetrical cracking behaviors around the inclusions.