The variable parameter rheological model of wood

How to establish the rheological model to simulate creep behavior of wood and wood-based composites under change-load has not been solved in research of wood rheology. This paper presents a new model—variable parameter rheological model. The bending creep behavior of small clear poplar specimens under different constant load levels were examined. The load levels within 50% of rupture load of the specimens, and the experimental creep behavior were simulated by the variable parameter Maxwell model. The results show that using only one model of variable parameters may simulate the creep behavior of wood under different constant load levels very well. Applying the generalized Boltzmanns superposition principle, the variable parameter rheological model can be used to simulate the creep behavior of wood under change-loads conveniently and accurately.