Mechanical Properties Flashcards
These are most commonly conducted for metals at room temperature
Stress-strain test
The three principal ways in which a load may be applied
Tension, Compression, and Shear
A gradually increasing tensile force that is applied uniaxially along the long axis of the specimen
Tension
A gradually increasing compressive force that is applied uniaxially along the long axis of a specimen
Compression
A load or force imposed parallel to the upper and lower faces, each of which has an area of A0
Shear
Is simply the instantaneous load applied over the cross sectional area before any load is applied
Engineering Stress
Is simply the deformation elongation or change in length at some instance over the original length before load is applied
Engineering Strain
Is always dimensionless
Strain
The maximum stress on engineering stress-strain curve
Tensile Strength
Also called as the ultimate strength
Fracture
Acts as a stress concentrator
Neck
In metals, this occurs when a noticeable necking starts
Tensile Strength
In polymers, it occurs when polymer backbone chains are aligned and about to break
Tensile Strength
Another term for the modulus of elasticity
Young’s Modulus
Is the relationship between engineering stress and engineering strain for elastic deformation
Hooke’s Law
Is deformation in which the stress and strain are proportional
Elastic Deformation
What is represented by the ordinate in a stress-strain diagram?
Stress
What is represented by the abscissa in a stress-strain diagram?
Strain
May be thought of as stiffness, or a material’s resistance to elastic deformation
Modulus of Elasticity (E)
Is nonpermanent, which means that when the applied load is released, the piece returns to its original shape
Elastic Deformation
Corresponds to the slope of the linear portion of the stress-strain graph
Modulus of Elasticity (E)
Is a time-dependent elastic behavior
Anelasticity
It is the ratio of the lateral and axial strains
Poisson’s Ratio
Occurs when stress is no longer proportional to strain which results to a deformation that is permanent and nonrecoverable
Plastic Deformation
It is the stress level at which plastic deformation begins
Yielding
Stress at which noticeable plastic deformation has occured
Yield Strength
The stress corresponding to the intersection of this line and the stress-strain curve as it bends over in the plastic region
Yield Strength
May be determined as the initial departure from linearity of the stress-strain curve
Proportional Limit
It is a measure of the degree of plastic deformation that has been sustained at fracture
Ductility
Refers to when a metal experiences very little or no plastic deformation upon fracture
Brittle
Is the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading, to have this energy recovered
Resilience
Is the strain energy per unit volume required to stress a material from an unloaded state up to the point of yieding
Modulus of Resilience
Ability of a material to store energy
Resilience
Is a property that is indicative of a material’s resistance to fracture when a crack is present
Toughness
Is the ability of a material to absorb energy and plastically deform before fracturing
Toughness
Energy to break a unit volume of material
Toughness
Is defined as the load F divided by the instantaneous cross-sectional area over which deformation is occurring
True Stress
Is defined when no volume occurs during deformation
True Strain
Is a measure of a material’s resistance to localized plastic deformation
Hardness
Resistance to permanently indenting the surface
Hardness
