Quiz 1. Intro to Composites

Choose the necessary “ingredients” for the definition of a composite (multiple answers possible)

• two constituents, at least

• air

• inclusions larger than molecules

• well-defined structure

• periodic structure

In this course, we focus on (multiple answers possible)

• deriving effective properties

• particulate composites with improved strength

• property-structure relations

• biological composites

• dynamic properties of foams

Most composites cannot be considered as…

• elastic media

• homogeneous media

• structured media

• isotropic media

• 3x3

• 4x4

• 2x2

• depends on the problem under consideration

A solid body made of a homogeneous isotropic material is loaded by pressure uniformly distributed over its entire surface. How many elastic moduli do we need to know to complete describe its deformed state?

• 1

• 2

• 3

• 4

A beam made of a general anisotropic material is subject to tensile load along a single direction. How many elastic constants do we need to describe its deformed state?

• 3

• 6

• 21

• 36

If someone wants to improve the toughness of a composite, which type of inclusions would you advise?

• rounded particles

• fully aligned fibers

• random platelets reinforcement

• nanoparticles

Fibrous composites have … (multiple answers are possible)

• larger weight due to a dense concentration of fibers

• delamination issues

• fibers stiffer than the matrix

• always an anisotropic response

Rules of mixtures … (multiple answers are possible)

• allow estimating the bounds on the elastic moduli of constituents

• provide accurate estimation of the effective moduli of a composite

• fully neglect the structure of composites

• can be used when finite-element simulations are not possible

• provide more accurate results than the Hashin-Shtrikman bounds

Micromechanics… (multiple answers are possible)

• provides clear and straightforward guidelines on selecting an RVE (representative volume element)

• is applicable only to periodically structured composites

• aims at deriving homogenization rules

• gives a set of techniques to estimate the effective elastic properties of a composite

• can be used to reconstruct the microstructure of a composite based on given effective properties