EXTRACTING THE EFFECTIVE CONSTITUENTPROPERTIES OF DAMAGED UNI-DIRECTIONALCOMPOSITE LAMINA

摘要

Damage in laminated composite structures made up of uni-directional laminae is typicallyrndefined, measured, and analyzed as a reduction of thermo-mechanical properties of therncomposite laminae. However, damage in a composite lamina results from damage in thernconstituents. Therefore, composite damage can be expressed as constituent damage that isrnnecessary for damage modeling using Multicontinuum Technology (MCT). A method to reversernengineer the effective damaged constituent properties that produce the damaged laminarnproperties utilizing a finite element micromechanics model and multi-continuum technology isrndiscussed. The method used to estimate the constituent properties from lamina properties is anrniterative process that requires damaged composite lamina properties and some of the constituentrnproperties. Using this method, a degraded lamina with cracks is effectively described as arncontinuum with a combination of reduced and intact constituent properties. The method isrnimplemented for two possible matrix failure/damage modes. The first is a matrix failure modernwith the matrix crack-face perpendicular to the intact fibers, termed here as matrix normalrncracking. The second mode is the classical matrix transverse cracking with transverse ply cracksrnrunning parallel to the fibers. Results of this reverse engineering method are presented for theserntwo failure modes.