Abstract:
For wood beams, it is often assumed that the neutral axis is located at the centroid of the
beam. The neutral axis of isotropic, homogeneous materials is located at the centroid of the
material, but wood is neither isotropic nor homogeneous. The varying grain patterns and
knots located throughout wood are points of discontinuity that make wood anisotropic and
non-homogeneous. In fact, wood is an orthotropic material, meaning that it has properties
that are different in three mutually perpendicular directions. Because of this, research is
needed to determine the location of the neutral axis of wood materials to gain a better
understanding of the behavior of wood beams. This project used Digital Image Correlation
and VIC-3D software to analyze 1in by 1in and nominal 2in by 4in wood beams when loaded
in bending. Axial strain plots were used to determine the location of the neutral axis. From
the data obtained, it was determined that the neutral axis of 1in by 1in wood beams is located
below the centroid and for 2in by 4in beams the neutral axis is located above the centroid.
Additionally, it was determined that knots will change the location of the neutral axis
depending on their location in the beam.
