Quiz: Section 3.3 Evaluation of Four Elastic Moduli

1. How much is the maximum possible fiber volume fraction for circular fibers arranged in a square array?

86.93 percent.

78.54 percent.

90.69 percent.

70.23 percent.

2. How much is the maximum possible fiber volume fraction for circular fibers arranged in a hexagonal array?

78.54 percent.

86.93 percent.

90.69 percent.

70.23 percent.

3. Concerning the Halpin-Tsai equations for transverse elastic modulus, what does the reinforcing factor depend on?

packing geometry.

Young’s modulus of the matrix.

fiber volume fraction.

Young’s modulus of the fibers.

4. The longitudinal modulus of a lamina is dependent on which of the following. (Check all that apply)

matrix Young’s modulus.

Poisson’s ratio of fiber.

Poisson’s ratio of matrix.

fiber Young’s modulus.

fiber volume fraction.

5. Longitudinal modulus of a lamina is greater than

fiber Young’s modulus if fiber Young’s modulus is greater than the matrix Young’s modulus.

fiber and matrix Young’s modulus.

matrix Young’s modulus if matrix Young’s modulus is less than the fiber Young’s modulus.

6. What material type does a unidirectional lamina with a random, hexagonal, or square arrangement best fall under?

anisotropic.

orthotropic.

monoclinic.

transversely isotropic.

7. Assuming the same fiber volume fraction, which unidirectional lamina generally has the largest longitudinal elastic modulus?

glass/epoxy.

graphite/epoxy.

boron/epoxy.

8. Assuming the same fiber volume fraction, which unidirectional lamina generally has the lowest shear modulus?

boron/epoxy.

graphite/epoxy.

glass/epoxy.

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