21.3: Singularity Functions for Shear
In structural analysis, singularity functions are crucial in simplifying the representation of shear forces in beams under discontinuous loading. These functions describe discontinuous variations in shear force across a beam with varying loads by using a single mathematical expression, regardless of the complexity of the loading conditions. The singularity functions are derived from creating a free-body diagram of the beam and then making conceptual cuts at specific points to examine the shear force in each section. This is defined by
Where W and L are the width and length of the beam, respectively. Macaulay's brackets < > are an essential feature of singularity functions. These brackets help evaluate the function based on the position along the beam about specific points of interest. The notation adjusts the function's value to account for the beam's condition at different sections, enabling these functions to be treated like standard mathematical expressions for purposes of differentiation and integration.
For example, when dealing with a point load placed at a certain point along the beam, singularity functions allow for a straightforward representation of the abrupt change in shear force at that location. By breaking down complex beam loadings into simpler components, the overall shear force across the beam can be easily determined by combining the functions associated with each type of loading.
