Failure of fiber reinforced orthotropic layers.
Failure of fiber reinforced orthotropic layers.Failure often controlled by the complex interaction of fibers and matrix.Still, the ideal was to come up with failure criteria that are small generalization of those used for isotropic materials.
(a,b) fiber microbuckling; (c) kink band; (d) shear failure on 45-deg plane.
How many experiments?
Max stress and max strain criteriaMax stress (note that these are no longer principal stresses)
Max strain
Example 6.2.1
Solution procedure
Tensile strength
Comparing tensile to compressive strength
What changed about the envelope?
Biaxial loadingAnything remarkable?
Tsai-Hill Criterion
Hoffman criterionOscar Hoffman, Lockheed 1967To account for difference in tension and compression need to have linear terms
Derivation as homework.Criterion is no longer homogeneous. What does that mean?Implication for safety factors. Have a paper on that with A. Groenwold of U. Stellenbosch.