Engineering Materials and Their Applications: Composites

What are composites?

How are large particle composites defined?

What is the rule of mixtures in composites?

How are composites classified in this discussion?

What is the function of the matrix in composites?

Provide an example of a large particle composite.

What does the critical fiber length (lc) depend on?

What is the influence of fiber orientation and concentration on fiber-reinforced composites?

What is the total load sustained by the composite in the case of elastic behavior under longitudinal loading?

What are the two possible extremes in fiber orientation for fiber-reinforced composites?

What is the influence of the interfacial bond between the fiber and matrix phases on the mechanical properties of a fiber-reinforced composite?

What does the modulus of elasticity versus volume percent tungsten graph represent?

What is the effect of increasing fiber length on fiber reinforcement in a fiber-reinforced composite?

What is the influence of the mechanical properties of a fiber-reinforced composite on the fiber's properties and load transmitted by the matrix phase?

What is the significance of critical fiber length (lc) for composite material strengthening and stiffening?

What are the factors that influence the mechanical properties of continuous and aligned fiber composites under longitudinal loading?

Composites are artificially produced multiphase materials having desirable combinations of the best properties of the constituent phases. Usually, one phase (the matrix) is continuous and completely surrounds the other (the dispersed phase). In this discussion, composites were classified as ______, fiber-reinforced, and structural.

Large-particle composites are polymeric materials with fillers, improving properties and/or replacing some polymer volume with a less expensive material. Concrete is a common example, composed of cement (the matrix) and sand and gravel (the ______).

The behavior of a two-phase composite is influenced by the volume fraction of the constituent phases, with mechanical properties being enhanced with increasing particulate content. Two mathematical expressions predict that the elastic modulus should fall between ______ and lower bounds.

The behavior of a two-phase composite is influenced by the volume fraction of the constituent phases, with mechanical properties being enhanced with increasing particulate content. Two mathematical expressions predict that the elastic modulus should fall between upper and ______ bounds.

Composites are artificially produced multiphase materials having desirable combinations of the best properties of the constituent phases. Usually, one phase (the matrix) is continuous and completely surrounds the other (the dispersed phase). In this discussion, composites were classified as particle-reinforced, ______, and structural.

Composites are artificially produced multiphase materials having desirable combinations of the best properties of the constituent phases. Usually, one phase (the matrix) is continuous and completely surrounds the other (the dispersed phase). In this discussion, composites were classified as particle-reinforced, fiber-reinforced, and ______.

The modulus of elasticity is denoted by E and the volume fraction is denoted by V, whereas the subscripts c, m, and p represent composite, matrix, and particulate phases. Figure 1.2 Modulus of elasticity versus volume percent tungsten for a composite of tungsten particles dispersed within a copper ______.

Critical fiber length (lc) is crucial for composite material strengthening and stiffening, influenced by fiber strength ((\sigma_f^*)), diameter (d), and fiber-matrix bond strength/matrix shear yield strength (τc). Figure 1.4 Stress–position profiles when fiber length l (a) is equal to the critical length lc, (b) is greater than the critical length, and (c) is less than the critical length for fiber-reinforced composite that is subjected to a tensile stress equal to the fiber tensile ______.

As fiber length l increases, the fiber reinforcement becomes more ______.

Continuous and Aligned Fiber Composites Tensile Stress–Strain Behavior—Longitudinal Loading The mechanical properties of this type of composites depend on factors like fiber and matrix phase stress-strain behaviors, phase volume fractions, and load ______.

The properties of an aligned composite are highly ______, influenced by measurement direction. Figure1.6 (a) Schematic stress–strain curves for brittle fiber and ductile matrix materials. Fracture stresses and strains for both materials are noted. (b) Schematic stress–strain curve for an aligned fiber–reinforced composite that is exposed to a uniaxial stress applied in the ______ of alignment.

Elastic Behavior—Longitudinal Loading The total load sustained by the composite Fc is equal to the sum of the loads carried by the matrix phase Fm and ______.

The interfacial bond between the fiber and matrix phases is crucial for load transmittance, which ceases under stress, resulting in matrix ______.

Figure 1.5 Schematic representations of (a) continuous and aligned, (b) discontinuous and aligned, and (c) discontinuous and randomly oriented fiber–reinforced ______.

Influence of fiber orientation, concentration, and distribution significantly impact the strength and properties of fiber-reinforced composites, with two possible extremes in ______.

The mechanical properties of a fiber-reinforced composite depend on the fiber's properties and the load transmitted by the ______ phase.