Response of a body to
stress
deformaation
Strain is ___________ when any two
portions of the body that were similar in form and orientation remain the same before and after deformation.
homogenous
If one or more of these factors are not met, the strain is?
i. Originally straight lines remain straight.
ii. Originally parallel lines remain parallel.
iii. Circle becomes ellipses; spheres become ellipsoids.
Heterogenous
Strain variations can be due to the different mechanical behaviors of components of a rock or association of rocks.
One may reduce heterogeneous deformation to homogeneous
domains by decreasing the size of the studied volume.
Presence of relatively rigid components can result in more intense strain concentrated into weaker parts of the rock rather than beiing evenly distributed.
Homogenous-heterogenous Strain
T or F
A homogeneous deformation
on one scale may be part of a
heterogeneous deformation
on a different scale.
T
Series of movements that affect a body from its initial
undeformed stage to its deformed state.
Progressive Deformation
T or F
Progressive deformation cannot be both continuous nor discontinuos.
F, they can be.
total strain acquired by a body up to the time of measurement.
Strain Rate
intermediate strain steps towards
the final configuration
Incremental Strain
each increment can be divided into a series of smaller and smaller increments. When the duration tends to zero, the extremely small amount of strain is termed _____________.
Infinitesimal / Instantaneous
measure of strain that compares
the initial and final configurations
finite strain
The sequence of strain states through which the object passed during progressive deformation.
Strain Path
changes in the lengths of lines
linear strain
if elongation is positive, what occured is ________
extension
if elongation is negative, what occured is ________
shortening
changes in angles of lines
Shear Strain
amount a vertical line has
been rotated with respect to
a horizontal line.
angular shear
changes in volume
volumenric strain (dilational strain)
If homogeneously strained, a 2D-body will have at least two
___________ __________ that do not rotate relative to each other; their
angle remains the same before and after strain.
material lines
T or F
A material line
is made up of a series
of points in a body.
T
represents the cumulative,
total deformation;
Finite Strain Ellipse
represents the strain for an
instant in time.
Infinitesimal ellipse
Graphical representation to
visualize the amount of linear
and angular strain involved
in the deformation of rock.
Strain Ellipse
Defined by the longest (X) and shortest (Y) axis = _____________ ___________ ___________
principal strain axes
