A COMPARISON BETWEEN THE CLASSICAL BEAM THEORIES BASED ON EQUIVALENT SINGLE LAYER AND MURAKAMI’S ZIGZAG THEORY.

Resumo

The necessity for better properties materials has made advances in the composition of
structural elements such as composite beams introduced in the fields of civil, marine, aerospace
and mechanical engineering, which requires better material properties. However, the rapid
increase in using composite materials required improvements in the kinematics of classical
beam theories made to describe the mechanical properties of composited laminated beams. This
paper presents a comparison between the Euler-Bernoulli Theory (EBT) and Timoshenko Beam
Theory (TBT), applying in laminated composited beams associated with multilayer composite
analysis theories: Equivalent Single Layer (ESL) and Murakami’s ZigZag Theory (MZZ). The
work reported here shows examples of different beam configuration and loading, subject to
both theories. It was possible to compare the results with the exact solution derived by Pagano
[1]. Defining the length/thickness relation in which these theories are valid. EBT presents
precise results for low thickness beams; however, it presents low precision in the interlaminar
stress analysis. To contour this limitation and get better results in the stress field this paper used
the equilibrium equations of the elasticity theory. Meanwhile, TBT presents more accurate
results for thicker laminate beams, and the effects of transverse shear deformation are more
relevant in these cases. This article recognizes that TBT is more precise than EBT in all
comparisons presented and can represent the mechanical properties with certain precision and
simplicity.