Seismic performance of functionally graded diagonal braced structures

Abstract

This paper investigates the usage of functionally graded beam as a bracing member in building-type structures subjected to severe ground motions. Material distribution of functionally graded beam follows power law form along thickness direction. Equivalent stiffness of functionally graded brace (FGBr) is derived and confirmed analytically through applying strain energy equilibrium and appropriate boundary conditions on Euler-Bernoulli beam element for simulation of brace behavior. The seismic response analyses of single and multi-storey shear-type buildings with FGBrs are performed on lumped mass-stiffness models. This modeling technique is validated in terms of fundamental natural periods by continuous and numerical solutions. The effect of varied Young’s modulus and power law exponent on maximum responses such as displacement, storey drift and base shear is evaluated under both harmonic and severe earthquake motions.