Triaxial Braid
Composite Modeling
Presented by: Luke Walker
Funded by: Wyoming NASA Space Grant
Overview
• Project Introduction
– Finite Element Method
• Background Information
– Materials
– Experimental Research
• Methods
• Results
• Conclusions
Project Introduction
MD
CD
• Composites
– Strength to stiffness
– Materials of the future
BD
• Finite Element Method
• Tri-axial Braid
– Needs Characterized
Finite Element Method Background
• Numerical method
• Breaks part into elements
– Retain the properties of the whole part
• Used to solve complex problems
Previous Research
• Lomov, Ivanov
ε ε ε
2.E+04 1 2 3
2.E+04
– Acoustic emission 2.E+04
Accumulated 1.E+04
– Strain mapping Acoustic 1.E+04Emissions
Energy 1.E+04
(kV2 µs)
– X-Ray 8.E+03
6.E+03
4.E+03
– Location of damage 2.E+03
0.E+00
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Percent Strain
University of Wyoming’s Progress
• Working model
– Python code generates model within Texgen
– Fortran code modified boundary conditions
– ABAQUS model created
– Volume average code written to validate
Model Contributions
• Straightening the braids
• Material properties dependence on:
– Fiber volume fraction
– Number of nodes
• Generate results for failure predictions
Model Contributions
Straightening Braids
• Fully Defines Model
After
• Smaller Volume Average Before
• Eliminates Nesting
Model Contributions
Increasing Volume Fraction
• Removed Corner
Matrix
• Required for
conclusions to be made
based off of
experimental results.
Model Contributions
Possion’s Ratio vs. Volume Fraction
Model Contributions
Stiffness vs. Volume Fraction
Model Contributions
Effect of Increasing Complexity of Model
Conclusions
• Straightening of the braids allowed for the
stresses to be broken down into various
sections.
• Possion’s ratio does not depend on volume
fraction.
• Stiffness depends on the volume fraction
Conclusions
• Neither stiffness or Possion’s ratio depends on
the number of nodes.
• Failure Criterion
• Validation of experimental results
Questions?