Creep performance and life prediction of bamboo scrimber under long-term tension in parallel-to-grain

Abstract

In order to study the long-term tensile creep properties of bamboo scrimber, this paper conducted long-term tensile creep tests in parallel-to-grain of bamboo scrimber in the indoor environment, and studied the creep failure mode, creep strain and creep compliance of bamboo scrimber in the long-term tensile. Furthermore, we proposed a unified creep life prediction method at the full stress level. The method included fitting the theoretical model of creep compliance of bamboo scrimber under long-term tension by using the multi-branch Kelvin-Voigt model, fitting the shear relaxation model in the form of Prony series by using the multi-branch generalized Maxwell model, establishing the creep finite element model of the bamboo scrimber specimen in the parallel-to-grain tension, and establishing the creep life prediction model of the bamboo scrimber in the parallel-to-grain tension based on the creep failure rule and the creep deformation data calculated by the finite element model. The results showed that the creep strain curve of bamboo scrimber included unstable creep stage and stable creep stage without accelerated creep stage. The specimen broke instantaneously in the last 1 second, and the fracture shape showed as flush fracture and oblique fracture. Under 70% of the ultimate load level, the creep characteristics of the bamboo scrimber in the parallel-to-grain tension were linear viscoelastic, and the creep compliance was basically independent of the load level. The creep finite element model of bamboo scrimber tensile specimen could accurately calculate the creep deformation of the bamboo scrimber. The creep life prediction model could accurately predict the creep life of bamboo scrimber at the full tensile stress level in parallel-to-grain.