Publications

Validation of carbon-fiber laminate simulations with low velocity impact experiments

English, Shawn A.; Nelson, Stacy M.; Krafcik, Karen L.; Moore, David G.; Kernen, Burke L.; Briggs, Timothy B.

Presented is a model verification and validation effort using low velocity impact (LVI) of carbon fiber reinforced polymer laminate experiments. The flat cylindrical indenter impacts the laminate with enough energy to produce delamination, matrix cracks and fiber breaks. Included in the experimental efforts are ultrasonic scans of the damage for qualitative validation of the models. However, the primary metrics of validation will be the force time history measured through the instrumented indenter and initial and final velocities. The simulations, which are run on in-house software, will consist of all physics and material parameters of importance as determined by a sensitivity analysis conducted on the full LVI simulation. The orthotropic damage and failure constitutive model used for the lamina is described in detail and material properties are measured, estimated from micromechanics or optimized through calibration. For all simulations of interest, the mesh and material behavior is verified through extensive convergence studies. An ensemble of simulations incorporating model parameter uncertainties is used to predict a response distribution which is then compared to experimental output. The result is a quantifiable confidence in material characterization and model physics when simulating this phenomenon in structures of interest.