Stress Analysis Flashcards
Name 5 ways a material can be stressed?
tension compression bending shear torsion
How is axial stress calculated?
force per unit area
stress = force/area
How is axial strain calculated?
amount of elongation or shortening
change in length/original length
What is young’s Modulus?
a measure of the ability of a material to resist elongation and compression (stiffness)
E = stress/strain
how are shear stresses caused?
forces acting in opposite directions to planes within a material
How is shear stress calculated?
shear force/shear area
What is shear strain?
angular deformation (angle sheared)
What is angular deformation measured in?
radians
What is the equation for sheer strain?
angle sheared (r) = distance sheared/distance between shearing forces
What is shear strength?
the maximum shear strength a material can withstand before fracture
shear force to fracture/ sheared area
What is another name for the shear modulus?
the modulus of rigidity
How is the modulus of rigidity calculated?
shear stress/shear strain
Which letter represent the modulus of rigidity?
G
Where does the largest shear stress occur?
at 45 degrees to the axial loading
what is equal to the largest shear stress?
half the axial stress
How does bending stress occur?
when a material is acted on by forces or moments that tend to bend or curve it
What are 2 common types of bending?
cantilever
3 point
When a material is bent, what is in between the compressed side and the elongated side?
neutral axis of no stress
In a complex shape like a bone, is the neutral axis always at its geometric centre?
Depends on the shape of the bone
What happens to stress the further a material is bent from the neutral axis?
increases
Where does maximum stress occur in bending?
the surface of the beam
Where will a material being bent, fail?
at the surface
What is the equation M = F x L used for?
bending moment calculation
What is second moment of area?
a measure of the distribution of a materials mass from the neutral axis
