Accelerated Interior Point Algorithms for Rate‐Independent Single Crystal Plasticity at Small Strains

ABSTRACT

Rate‐independent single crystal plasticity requires robust solution methods due to the non‐uniqueness of slip system activity. The interior point method, which enforces the yield criterion via slack variables and a so‐called barrier term, has proven both robust and computationally efficient for this class of problems and has been applied to crystal plasticity in small‐strain and large‐strain frameworks. A drawback of the classic interior point method is its nested loop structure, which increases computational cost and limits warm‐starting capabilities. In this work, we propose a fixed barrier parameter formulation that reduces the solution procedure to a single Newton loop and exploits history information from prior load steps to construct a near‐optimal initial guess. Numerical studies at the material point level for the small‐strain framework demonstrate that convergence is achieved on average in 2–3 interior point Newton iterations, with a stress response comparable to interior point and visco‐plastic approaches from the literature.