Macaulay Bracket
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Macaulay brackets are a notation used to describe the
ramp function The ramp function is a unary real function, whose graph is shaped like a ramp. It can be expressed by numerous definitions, for example "0 for negative inputs, output equals input for non-negative inputs". The term "ramp" can also be used for o ...
:\ = \begin 0, & x < 0 \\ x, & x \ge 0. \end A popular alternative transcription uses angle brackets, ''viz.'' \langle x \rangle.Lecture 12: Beam Deflections by Discontinuity Functions.
Introduction to Aerospace Structures. Department of Aerospace Engineering Sciences, University of Colorado at Boulder Another commonly used notation is x+ or (x)+ for the
positive Positive is a property of positivity and may refer to: Mathematics and science * Positive formula, a logical formula not containing negation * Positive number, a number that is greater than 0 * Plus sign, the sign "+" used to indicate a posi ...
part of x, which avoids conflicts with \ for
set notation In set theory and its applications to logic, mathematics, and computer science, set-builder notation is a mathematical notation for describing a set by enumerating its elements, or stating the properties that its members must satisfy. Defining ...
.


In engineering

Macaulay's notation is commonly used in the static analysis of bending moments of a beam. This is useful because shear forces applied on a member render the
shear and moment diagram Shear force and bending moment diagrams are analytical tools used in conjunction with structural analysis to help perform structural design by determining the value of shear forces and bending moments at a given point of a structural element such ...
discontinuous. Macaulay's notation also provides an easy way of integrating these discontinuous curves to give bending moments, angular deflection, and so on. For engineering purposes, angle brackets are often used to denote the use of
Macaulay's method Macaulay’s method (the double integration method) is a technique used in structural analysis to determine the deflection of Euler-Bernoulli beams. Use of Macaulay’s technique is very convenient for cases of discontinuous and/or discrete load ...
. :\^n = \begin 0, & x < a \\ (x-a)^n, & x \ge a. \end (n \ge 0) The above example simply states that the function takes the value (x-a)^n for all ''x'' values larger than ''a''. With this, all the forces acting on a beam can be added, with their respective points of action being the value of ''a''. A particular case is the
unit step function The Heaviside step function, or the unit step function, usually denoted by or (but sometimes , or ), is a step function, named after Oliver Heaviside (1850–1925), the value of which is zero for negative arguments and one for positive argume ...
, :\langle x-a\rangle^0 \equiv \^0 = \begin 0, & x < a \\ 1, & x > a. \end


See also

*
Singularity function Singularity functions are a class of discontinuous functions that contain singularities, i.e. they are discontinuous at their singular points. Singularity functions have been heavily studied in the field of mathematics under the alternative names ...


References

Mathematical analysis {{maths-stub