UNCERTAINTY QUANTIFICATION OF FINITE ELEMENT ANALYSIS OF UNI-AXIAL STRENGTH TEST OF HOLED COMPOSITE LAMINATES (*)

摘要

In the aerospace industry, open hole specimens of composite laminates have been used in standardized tests to generate design allowables. Using finite element method (FEM) based tool MicMac/FEA with ABAQUS code interface and statistical design of experiments, Shah, et al. in 2010 [11] studied average-property-based failure envelope with uncertainty estimates of open hole specimen with quasi-isotropic carbon fiber-epoxy laminate. However, their FEM model is deterministic, without uncertainty analysis. In this paper, based on Shah's FEM model, we developed FEM model of uni-axial strength test of holed composite laminates using ABAQUS with a serious of quadrilateral S4R and trilateral S3R shell element designs. The mesh density ranges from the original 8 × 8 (very coarse) to 48 × 48 (very fine). For each of the meshes, we compute the failure strength from Hasin failure criteria. Then we use a 4-parameter logistic function nonlinear least squares fit algorithm to obtain an estimate of the failure strength at infinite degrees of freedom (d.o.f) as well as its uncertainty at 50,000-d.o.f. and relative error convergence rates. Our results are then compared with Shah's with the additional advantage that our results have uncertainty quantification that can be compared with experimental data. The significance and limitation of our method on the uncertainty quantification of FEM model of uniaxial strength test of holed composite laminates are discussed. (*) Contribution of the U.S. National Institute of Standards and Technology. Not subject to copyright.