The variational-asymptotic method is used to obtain an asymptotically-exact
expression for the strain energy of a tapered strip-beam. The strip is assumed to be
sufficiently thin to warrant the use of two-dimensional elasticity. The taper is
represented by a nondimensional constant of the same order as the ratio of the
maximum cross-sectional width to the wavelength of the deformation along
the beam, and thus its cube is negligible compared to unity. The resulting
asymptotically-exact section constants, being functions of the taper parameter,
are then used to find section constants for a generalized Timoshenko beam
theory. These generalized Timoshenko section constants are then used in the
associated one-dimensional beam equations to obtain the solution for the
deformation of a linearly tapered beam subject to pure axial, pure bending, and
transverse shear forces. These beam solutions are then compared with plane
stress elasticity solutions, developed for extension, bending, and flexure of a
linearly tapered isotropic strip. The agreement is excellent, and the results
show that correction of the section constants using the taper parameter is
necessary in order for beam theory to yield accurate results for a tapered
beam.