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When analyzing an entire element, it is reasonable to calculate moments at both ends of the element, at the beginning, centre and end of any uniformly distributed loads, and directly underneath any point loads.
Obviously any "pin-joints" within a structure allow free rotation, and so zero moment occurs at these points as there is no means of transmitting revolving forces from one side to the other.
It is more common to use the convention that a clockwise bending moment to the left of the point under deliberation is taken as positive.
This then corresponds to the second derivative of a function which, when positive, indicates a curvature that is lesser at the centre' i.e. sagging.
When defining moments and curvatures, in this means calculus can be more willingly used to find slopes and deflections.
Critical values inside the beam are most frequently annotated using a bending moment diagram, where negative moments are plotted to scale above a horizontal line and positive below.
Bending moment varies linearly over unloaded sections, and parabolically over homogeneously loaded sections.
DISTANCE
OF POSITION BETWEEN ZERO BENDING MOMENTS
Moments
are considered by multiplying the external vector forces (loads or reactions)
by the vector distance at which they are practical.
When analyzing an entire element, it is reasonable to calculate moments at both ends of the element, at the beginning, centre and end of any uniformly distributed loads, and directly underneath any point loads.
Obviously any "pin-joints" within a structure allow free rotation, and so zero moment occurs at these points as there is no means of transmitting revolving forces from one side to the other.
It is more common to use the convention that a clockwise bending moment to the left of the point under deliberation is taken as positive.
This then corresponds to the second derivative of a function which, when positive, indicates a curvature that is lesser at the centre' i.e. sagging.
When defining moments and curvatures, in this means calculus can be more willingly used to find slopes and deflections.
Critical values inside the beam are most frequently annotated using a bending moment diagram, where negative moments are plotted to scale above a horizontal line and positive below.
Bending moment varies linearly over unloaded sections, and parabolically over homogeneously loaded sections.
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