Composite Materials and Strain Quiz

False (B)

0.002

<p>matrix</p> Signup and view all the answers

<p>Epoxy = Better bonding characteristics with fiber Polyester = Lower cost Vinylester = Moderate properties Polypropylene = Good flexibility</p> Signup and view all the answers

<p>Epoxy (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Starts the cross-linking process and sets the composite</p> Signup and view all the answers

<p>Shear stress and normal stress (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Ultimate stress</p> Signup and view all the answers

<p>zero</p> Signup and view all the answers

<p>Statically determinate (A)</p> Signup and view all the answers

<p>Ultimate stress = Used for predicting failure in brittle materials Longitudinal stress = Acts along the length of a structure Von Mises stress criterion = Applicable to ductile materials Plane strain = The strain is in one plane</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Zero</p> Signup and view all the answers

<p>Matrix and fiber strains are the same (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Aramid fiber reinforced composites</p> Signup and view all the answers

<p>fibers</p> Signup and view all the answers

<p>0.01 μm -- 0.1 μm (B)</p> Signup and view all the answers

<p>Iso-stress = Stress is uniform across the composite Iso-strain = Strain is uniform across the composite Dispersed phase = Fibers and particles in composites Thin-walled structure = Common assumption for fuselage design</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Either 0 degrees or 90 degrees</p> Signup and view all the answers

<p>parallel</p> Signup and view all the answers

<p>Conductive (C)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Concrete</p> Signup and view all the answers

<p>Resilience</p> Signup and view all the answers

<p>Metals = Good conductors of electricity Polymers = Less stiff compared to others Ceramics = High durability under compression Composites = Combines properties of multiple materials</p> Signup and view all the answers

<p>Ductility (D)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Elastic</p> Signup and view all the answers

<p>temperatures</p> Signup and view all the answers

<p>Carbon fiber reinforced (A)</p> Signup and view all the answers

<p>Body-Centered Cubic (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Makes the material stronger</p> Signup and view all the answers

<p>smart</p> Signup and view all the answers

<p>Less than 0.3% (D)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Plastic</p> Signup and view all the answers

<p>Linear defect (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Thermal properties</p> Signup and view all the answers

<p>solubility limit</p> Signup and view all the answers

<p>Iron (A)</p> Signup and view all the answers

<p>Toughness = Resistance to fracture Ductility = Ability to deform under tensile stress Hardness = Resistance to localized plastic deformation Resilience = Ability to absorb energy and deform elastically</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Minimum (C)</p> Signup and view all the answers

Ability of a material to deform plastically before fracture. It measures the extent of deformation a material can withstand before breaking.

The ability of a material to resist permanent deformation under stress. It represents how much stress a material can handle before it starts to deform permanently.

The maximum stress a material can withstand before it breaks. It's the point at which the material fails under tension.

The ability of a material to absorb energy before fracture. It represents how much energy it can take before it breaks.

The capacity of a material to deform elastically and return to its original shape after stress is removed. It measures how much energy the material can store and release.

The ratio of the stress to the strain in the elastic region of a material's behavior.

The ability of a material to withstand a force that tends to cause it to slide or shear along a plane.

The ability of a material to withstand compression without buckling or collapsing. It represents the material's resistance to crushing forces.

The ability of a material to resist scratching, indentation, or abrasion. It's a measure of the material's hardness.

The amount of stress a material can withstand while maintaining its integrity. It is calculated by dividing the applied strength by the yield strength.

In a composite material, the strain in the matrix is equal to the strain in the fiber. This means that both components deform at the same rate.

A type of composite where strong particles are dispersed in a weaker matrix, like concrete with aggregate.

In a composite material, the fibers or particles are referred to as the 'dispersed phase' because they are embedded within the 'matrix' material.

A type of composite material known for its exceptional ability to absorb impact energy due to its high tensile strength and flexibility.

The size range for particles in dispersion-strengthened composites, which enhances their strength by spreading tiny particles throughout the matrix.

The length of a fiber needed to fully utilize its strength in a composite material, determined by the fiber's diameter.

A composite laminate where all fibers are aligned in either 0 degrees or 90 degrees to the loading direction, creating a strong structure with high stiffness.

When a composite is subjected to load along its length, the strain in both the matrix and fiber is uniform, leading to an iso-strain condition.

A portion of a system with consistent physical and chemical properties throughout.

A material's ability to withstand deformation before fracturing.

Materials that respond to stimuli like temperature, pressure, or electric fields.

The detailed structure of a material as seen under a microscope.

The slowest rate of change towards an equilibrium state.

The stress that causes irreversible deformation in a material.

Structure with less tightly packed atoms, leading to lower density compared to other structures.

A type of material defect that occurs along a line or plane within the material.

The study of how materials respond to applied forces or loads.

The properties of a material that change with temperature or temperature gradients.

The inability of a solution to dissolve any more solute at a given temperature and pressure.

A material's resistance to fracture under stress. It's the amount of energy a material absorbs before breaking.

Strain is a measure of deformation. It is defined as the change in length per unit original length. Because it is a ratio of lengths, it has no units.

The strain offset is a small value used in constructing the yield strength line on a stress-strain curve. It is typically set at 0.002, indicating a 0.2% strain.

Modulus of elasticity, also known as Young's modulus (E), is a material property that describes its stiffness. It's calculated as the ratio of stress to strain in the elastic region of the stress-strain curve.

A brittle material fails with little or no plastic deformation. This means it breaks suddenly with minimal warning.

A catalyst, or hardener, is added to a composite to initiate the cross-linking process, which sets the composite material. This process creates strong bonds between the components, solidifying the composite.

Composite materials are anisotropic, meaning their properties vary depending on the direction. This is because the fibers and matrix have different properties and their orientation affects the overall behavior.

Epoxy resin is known for its excellent bonding characteristics with fibers, making it a popular choice for composites. It provides stronger, more durable bonds compared to other matrices.

Carbon fiber is commonly identified by its black color. It is lightweight, strong, and resistant to high temperatures.

Resultant stress is the combination of shear stress and normal stress.

Longitudinal stress acts along the length of the fuselage, the main body of the aircraft.

Ultimate stress is used to determine the failure point for brittle materials, which break suddenly without much deformation.

In plane stress problems, the thickness of the material is considered negligible because the stress is mainly in two dimensions.

A problem is statically determinate when the number of unknowns (like forces and reactions) is less than the number of independent equations.

In plane strain problems, the strain is confined to one plane, while the material might deform in other directions.

The Von Mises stress criterion is a mathematical formula used to predict yield (permanent deformation) for ductile materials, which can bend without breaking.

For thin metal sheets, stresses across the thickness are considered negligible because the sheets are designed to be strong in other directions.