6 - Materials Flashcards
Brittle
A brittle object shows little strain before reaching its breaking stress.
Compression
The result of two coplanar forces acting into an object, typically reducing its length.
Compressive Deformation
The change in an object’s shape due to compressive forces.
Ductile
A material is ductile if it can undergo large extensions without failure. Ductile materials can be stretched into wires.
Elastic Deformation
The material returns to its original shape when the deforming forces are removed. It does not remain permanently deformed.
Elastic Potential Energy
The energy stored in an object when stretched, equal to the work done to stretch it.
Extension
The increase in an object’s length.
Force-Extension Graph
A plot showing how an object extends as force is applied. For an elastic object, the gradient should be linear up to the limit of proportionality. The gradient gives the spring constant.
Hooke’s Law
The extension of an elastic object is directly proportional to the force applied, up to the object’s limit of proportionality.
Plastic Deformation
If a material deforms plastically, it will not return to its original shape when the deforming forces are removed. The object will be permanently deformed.
Polymeric
A material made from polymers.
Spring Constant
The constant of proportionality for the extension of a spring under a force. The higher the spring constant, the greater the force needed to achieve a given extension.
Strain
The ratio of an object’s extension to its original length. It has no unit since it’s a ratio of two lengths.
Stress
The amount of force acting per unit area. Its unit is the Pascal (Pa).
Tensile Deformation
The change in an object’s shape due to tensile forces.
Ultimate Tensile Strength
The maximum stress an object can withstand before fracture occurs.
Young Modulus
The ratio of stress to strain for a given material. Its unit is the Pascal (Pa).
