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4 CALCULATION OF CURVED BEAMS

4.1 Construction of the internal forces diagrams

In engineering design structures are often used in the form of rods
with curved axis - flat curved bars. These include lifting hooks,
arches, rings chains, rims and wheels pulleys etc.
In cross-section plane curve rod may have three internal power
factors: longitudinal force N , shear force Q , bending moment
M (fig. 4.1). For their determination using the method of
sections.

Figure 4.1

Longitudinal force N in any section is equal to the algebraic sum
of the projections of all forces located on one side of the section,
at a tangent to the axis of the rod, held in the considered section.
Longitudinal force N is considered positive if it causes tension,
and negative if compression causes.
Shear force Q in the section is the algebraic sum of all the forces
placed on one side of the section on planes. Shear force Q is
considered positive if it tries to return a vector of the rugged rod
clockwise relative to the proposed section.
Bending moment M in the cross section is the sum of points
relative to the center of gravity of the entire cross section of the
external load placed on one side of the section. Bending moment

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