Stress-strain behaviour of bamboo beyond its elastic limit under uniaxial compressive load, using the principles of plasticity and damage mechanics

Abstract

The experimental determination of the behaviour of bamboo under the action of monotonic uniaxial compressive loading and cyclic uniaxial compressive loading, as well as the subsequent formulation of mathematical models to study this behaviour are presented in this work. Several samples of the bamboo species Oxytenantera abyssinica, from the Congo Basin Rain Forest were tested to collect the necessary data for this study. Under the loading regimes applied, it was found that the behaviour of bamboo above its elastic limit is non-linear and this nonlinearity could be attributed to two distinct mechanical processes, which are plasticity and damage. These two degradation phenomena are best described by the theories of plasticity and continuum damage mechanics. A mathematical model, known as Fozao-Foudjet 2, that can be used to study the behaviour of bamboo under the monotonic uniaxial compressive load, beyond its elastic limit is proposed. This model has been obtained by modifying Mazars and Pijaudier-Cabot model from the study of the behaviour of concrete under similar loading regime. The major experimental parameters used to obtain the proposed model are computed from the tests results while others are obtained from a trial and error procedure. The stress-strain curves produced from the proposed mathematical model are compared with the test results and the comparison shows that the results from the model provide a good agreement with the test data.