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1.3 Deformation at the point

The change of linear dimensions of the body is called linear
deformation, the change of angular dimensions – angular
deformation. If a deformation changes by volume of a body, then
we can denote it as deformation at the point.
Let draw infinitesimal segments AB and AC through the
imaginary point A in the direction of the axes x and y (fig.1.6, b).
After loading the points A, B, C will move to the position А´, В´,
С´. The values:
 dx  dy
  ,  
y
x dy
dx
are called linear deformation at the point A in the direction of axes
x and y respectively.
The change of the original right angle between the segments AB
and AC is called angular deformation  at point A in the plane
xy
xOy .

a) b)

Figure 1.6

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