Defect sensitivity and Weibull strength analysis of monolayer silicene
RE Roman and SW Cranford, MECHANICS OF MATERIALS, 133, 13-25 (2019).
This paper analyzes ultimate tensile stress results from full atomistic reactive molecular dynamics (MD) simulations of monolayer silicene in terms of reliability using the Weibull probability of failure method (e.g., Weibull strength analysis). Both vacancy and interstitial defects and randomly distributed with prescribed densities upon a finite sheet of silicene and assessed for tension in both the zigzag and armchair directions, resulting in a significant decrease of strength. We demonstrate a clear directional dependency on the effect: mechanical properties in the zigzag direction are the most affected for both defect types. A single vacancy reduces the ultimate in-plane stress by approximately 13%, and one interstitial/adatom resulted in a strength reduction on the order of 24%, compared to the pristine state. Statistical analysis for the tensile strengths of indicate a Weibull modulus (m) on the order of approximately 50-150 depending on defect type and loading direction, using a best-fit approach via a Poisson distribution of defects, suggesting relatively high flaw tolerance once defects are present. Weibull analysis provides a method for determining the reliability of strength measurements in the analysis of data from future experimental assays of silicene.
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