Sensitivity of Simulated Anisotropy to Initial Texture Definitions

Free compression tests were performed on 0.040 inch thick 5754 aluminum sheet stock producing a slight in-plane anisotropy. A visco-plastic self-consistent (VPSC) deformation modeling code was used to model the mechanical properties and resultant deformation textures. Calculations using a discretized description of the initial texture simulated the deformation texture very closely. Simulation of the mechanical properties were also captured nicely with one exception. The direction of simulated in-plane anisotropy was reversed from the experimental results. Simulation of the impact of various texture components on the anisotropy indicted that the shift of texture toward stronger brass, {l_brace}110{r_brace}<112>, and Goss, {l_brace}110{r_brace}<001>, components led to the reversal of anisotropy. The simulated deformation texture was more intense than the experimental texture in the brass and Goss positions. This result suggests that the more intense simulated texture components may be responsible for the reversal of an isotropy

On uncertainty of a proportion from a stratified random sample of a small population

<div><p>This article considers the uncertainty of a proportion based on a stratified random sample of a small population. Using the hypergeometric distribution, a Clopper–Pearson type upper confidence bound is presented. Another frequentist approach that uses the estimated variance of the proportion estimator is also considered as well as a Bayesian alternative. These methods are demonstrated with an illustrative example. Some aspects of planning, that is, the impact of specified strata sample sizes, on uncertainty are studied through a simulation study.</p></div