Young's Modulus, Stress and Strain Flashcards
What is Stress?
A quantity that describes the distribution of internal forces within a body
symbol: sideways 6
What is the difference between tensile and compressive stress?
Tensile = + Compression = -
Why does stress affect the whole length of an object?
Has to be in equilibrium
How do you calculate stress with units?
Stress (Nm-2 / lbin-2 / Pa) = Force (N) / Area (m-2)
What is Strain?
A quantity that describes the deformations that occur within a body
How do you calculate strain with units?
strain (%) = extension (m) /length (m)
E = /\L/L
What is the load?
The force pulling on a sample of material
What is the symbol for Young’s modulus?
E
What is the equation for Young’s Modulus?
Young’s Modulus (Pa) = stress (Pa) / strain (%)
What is the Yield Point?
The stress where permanent deformation starts
What is the limit of proportionality?
The point at which the graph begins to curve
What is the elastic region and the plastic region?
Elastic = material will go back to original shape Plastic = material won't go back to original shape
What is ultimate tensile stress?
The max height reached on the graph, max stress a material can withstand
What is breaking strain?
the max strain a material can withstand
Why does the stress strain graph drop after elastic region?
necking - cross sectional area drops, less stress
