Optimizing beveled diamond anvils via finite element analysis

Diamond anvil cell (DAC) is a pivotal tool in high-pressure research, enabling the exploration of material behaviors under extreme conditions. However, achieving pressures beyond the current limits necessitates optimizing the geometric configuration of diamond anvil. To address this challenge, we developed a fourth-order strain energy function to capture the anisotropic, nonlinear, and large elastic deformations of diamond during DAC operation. In addition, an elastic instability criterion at finite strain was incorporated to identify the critical configuration of diamond anvils at the onset of defect nucleation. Based on this novel computational framework, finite element analysis (FEA) was conducted to evaluate how culet diameter, friction coefficient, bevel angle, and bevel diameter influence the performance of diamond anvils. An empirical equation was subsequently derived to quantitatively link the mechanical performance to the geometric configuration of beveled diamond anvils. The developed framework enables reliable simulation and prediction of diamond anvil performance, particularly for anvils with culet sizes around 20 μm, a critical yet experimentally challenging regime often regarded as key to surpassing current pressure limits. This work not only advances the fundamental understanding of diamond anvil mechanics but also provides a robust tool to guide the design of next-generation DAC configurations for ultra-high-pressure experiments.