BLOCCO 3
Name one standard test method for measuring hardness.
Rockwell
In which region of the stress-strain curve does a material return to its original size and shape after the stress is removed?
Elastic region
Which type of material resists high stresses but has no capacity for deformation and breaks suddenly?
Hard-brittle
What two types of behavior do viscoelastic materials possess?
Viscous and elastic behavior
What characteristic defines viscoelastic materials?
Stress-strain relationship depends on time
What is the primary purpose of characterizing materials before utilizing them?
To understand their properties
What is the standard unit for stress, also known as Pa?
Pascal
What number of cycles is considered a representative limit for normal fatigue failure?
10^7 cycles
Which mode of deformation involves pulling forces that elongate a material?
Tension
What is the term for the deformation of an object in response to an applied force?
Strain
A higher value of Young's modulus (E) indicates what about a material's deformation?
More difficult deformation
What does the area underneath the stress-strain curve represent for a material?
Toughness
What is the term for the permanent change in a material's shape after the applied stress is removed?
Plastic deformation
What is the formula for shear strain (γ) in terms of angle α?
γ = tan α
What is dynamic fatigue failure?
Failure at a stress lower than required for single application failure due to repetitive stress
Which of the following is NOT one of the three stages of fatigue failure?
Elastic deformation
In a viscoelastic material, what happens to the energy that is not recovered upon removal of the load?
It is dissipated in the form of heat
Which of these is a type of force or stress applied to a material?
Tension
In the plastic region, how does strain change in relation to the applied stress?
Strain changes are no longer proportional to the applied stress
Which of the following properties describes a material's resistance to bending, scratching, abrasion, or cutting?
Hardness
Which of the following is NOT listed as a general material property?
Biological
What happens to elastic materials when the applied force is removed?
They return to original shape
According to Hooke's Law, how does strain relate to applied stress?
Strain increases in direct proportion to the applied stress
What is the formula for Young's modulus (E)?
E = stress / strain
What are the three types of strain associated with different types of stresses?
Tensile, compressive, and shear strain
What percentage of residual strain is typically used to define the offset-based yield point?
0.2% or 1%
How is stress defined in terms of force and area?
Force per unit area
What is the formula for calculating strain (ε)?
Deformed length - original length / original length
Which material type is characterized by a 'necking' section after the elastic region, indicating permanent deformation?
Metallic materials
The point on the stress-strain curve where permanent deformation begins is known as the:
Yield point