A one-dimensional elasto-viscoplastic model coupled to damage for the description of creep in wooden materials

Abstract

This work focuses on the development of a model for the description of the tertiary creep phenomenon in wooden materials. We stared from an extended standard solid body model capable of best describing primary and secondary creeps. We then modify this model by introducing a damage variable to explain and model the rapid growth of viscoplastic strain during tertiary creep. We obtain a model comprising a reduced number of parameters (05) all physically interpretable; which can be easily determined from the results of creep tests. The proposed model has been tested using the experimental results of creep-rupture tests and it has been shown to be very suitable for describing the three phases of creep, with a relative error of less than 1%. The breaking time proposed by the model is lower, but very close to the experimental breaking time (Err = 0.01). The time to failure is easily accessible, thanks to the simplicity of our model, without necessarily going through heavy algorithms. This represents a significant advantage of our model, which in sum offers both a more realistic way of describing the three phases of creep by fully accounting for the phenomenon of damage during the tertiary phase, and a simple and fast way to analyze the rupture time, compared to other models in the literature. Our model is therefore presented as a good alternative for modeling the behavior of wood material under creep stress.

Experimental Investigation of Quasi-Static and Dynamic Impact Resistance in Thin Wood Veneer Laminates

“…Wood can undergo complex viscoelastic and viscoplastic deformation [10,11]. Pang et al [12] demonstrated strain-rate dependencies of Beech wood with compressive yield and ultimate stresses increased by around 250% when comparing quasi-static and transient-dynamic loads with strain rates of up to 2000 s −1 .…”

Modelling of creep behaviour of timber dowelled beams

“…10 Many attempts have been curried out to ascribe these properties to the micro-structure behaviour. Foth et al 11 introduced a description of the tertiary creep phenomenon in wooden materials using the experimental results of creep-rupture tests under creep stress. Two-step extrusion process, and mechanical properties such as strength, elastic modulus and Poisson's ratio of Wood Plastic Composite were investigated in.…”