Accession Number:

ADA456697

Title:

Modeling Fracture in Z-Pinned Composite Co-Cured Laminates Using Smeared Properties and Cohesive Elements in DYNA3D

Descriptive Note:

Master's thesis, Aug 2005-Sep 2006

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT

Personal Author(s):

Report Date:

2006-09-01

Pagination or Media Count:

105.0

Abstract:

The purpose of the present research was three-fold 1 gain a more sophisticated understanding of the response of co-cured composite joints with and without through-thickness reinforcement TTR, 2 compare the behavior of specimens reinforced with various sizes and densities of reinforcement, and 3 use experimental data to verify the existing DYNA3D smeared property model. Double cantilever beam, end-notch flexure and T-section specimens reinforced with 0.011 diameter z-pins at 2 and 4 volume densities were tested to determine the mode I, mode II and mixed mode I and II behavior. Results were added to preliminary research in which tests were conducted on previously mentioned specimen geometries reinforced with 0.022 diameter z-pins at similar densities. Experiments were modeled in DYNA3D using shell and cohesive elements. The energy release rate, G, determined through a curve fit developed from beam theory, was smeared across the region of reinforcement treating it as a separate material. The research validated Z-pinning as an effective means of improving the fracture toughness of polymer matrix laminated composites in mode I and mixed mode loading conditions and determined that the existing model works well in simulating the behavior in mode I tests.

Subject Categories:

  • Laminates and Composite Materials
  • Numerical Mathematics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE