Table of Contents
Advertisement
4�1�2�
Bending analysis
When a circular beam bends, tension and compression are produced inside the beam. Some parts of the beam are
pushed together, while some others are stretched.
The following image shows an overlay of a bent beam on top of the original, straight beam.
The bottom surface of the beam gets longer in length, while the top surface of the beam gets shorter in length. Also,
along the center of the beam – also known as the neutral axis –, the length doesn't change. The bottom surface is
under tension, while the top surface is under compression. Furthermore, the displacement of the beam varies linearly
from the top to the bottom – passing through zero at the neutral axis.
The stress distribution through a cross section of the beam shows that, when bending, a peak in tension appears on
the surface of the beam.
Measuring this peak tension is of interest to understand if the beam is overloaded. Any overloaded object is likely to
crack where it suffers the maximum tension.
Bending is in many cases not visible to the naked eye, therefore measuring the maximum tension suffered by the
beam becomes a tedious, time wasting and complicated task without knowing the direction in which the beam is
bending.
In scenarios where bending is present along with extension, such as in the tie bars of an injection molding machine,
die casting machine or any 4-Column press, even the invisible bending is a concern. This is because the beam's
tension due to bending is summed with the tension due to extension, resulting in a total maximum tension that could
be above the recommended safe values for the material.
With 4 QE2008-W sensors mounted around the circular beam, it is immediate to measure the total maximum tension
on the beam. In addition, this mounting configuration allows to extrapolate the direction in which the bending occurs.
26 / 56
Subject to technical modifications
Bending
Direction
Maximum
Tension
Angle of
Bending
Advertisement
Table of Contents
