Textile composites have a wide variety of applications in the aerospace, sports,
automobile, marine and medical industries. Due to the availability of a variety of textile
architectures and numerous parameters associated with each, optimal design through
extensive experimental testing is not practical. Predictive tools are needed to perform
virtual experiments of various options. The focus of this research is to develop a better
understanding of linear elastic response, plasticity and material damage induced nonlinear
behavior and mechanics of load flow in textile composites.
Textile composites exhibit multiple scales of complexity. The various textile
behaviors are analyzed using a two-scale finite element modeling. A framework to allow
use of a wide variety of damage initiation and growth models is proposed. Plasticity
induced non-linear behavior of 2x2 braided composites is investigated using a modeling
approach based on Hill’s yield function for orthotropic materials. The mechanics of load
flow in textile composites is demonstrated using special non-standard postprocessing
techniques that not only highlight the important details, but also transform the extensive
amount of output data into comprehensible modes of behavior.
The investigations show that the damage models differ from each other in terms
of amount of degradation as well as the properties to be degraded under a particular
failure mode. When compared with experimental data, predictions of some models
match well for glass/epoxy composite whereas other’s match well for carbon/epoxy composites. However, all the models predicted very similar response when damage
factors were made similar, which shows that the magnitude of damage factors are very
important.
Full 3D as well as equivalent tape laminate predictions lie within the range of the
experimental data for a wide variety of braided composites with different material
systems, which validated the plasticity analysis. Conclusions about the effect of fiber
type on the degree of plasticity induced non-linearity in a ±25° braid depend on the
measure of non-linearity.
Investigations about the mechanics of load flow in textile composites bring new
insights about the textile behavior. For example, the reasons for existence of transverse
shear stress under uni-axial loading and occurrence of stress concentrations at certain
locations were explained.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2405 |
| Date | 15 May 2009 |
| Creators | Goyal, Deepak |
| Contributors | Whitcomb, John D. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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