Determining an Optimum Model forthe Bending of Eucalyptus regnans Wood Heated by Microwave Energy

摘要

Microwave wood bending involves softening wood using microwave energy and then bending it into a required shape. An experimental framework was developed that included two sets of experiments: microwave mechanical property experiments (MMPE) and microwave wood-bending experiments (MWBE).This article reports on an investigation into the effect of the salient wood-bending variables on important mechanical and bending characteristics of Eucalyptus regnans wood, using a full factorial experimental framework and associated statistical analysis. Variables investigated were moisture content in the range of 18 to 20 percent and above 35 percent; wood temperature in the ranges of 80°C to 85°C, 100°C to 105°C, and 120°C to 125°C; MMPE for three wood strain rates of 0.1, 0.2, and 0.6 mm/s;and MWBE for three strain rates of 137s, 277s, and 817s.This article reports on two objectives: (1) the development of a full factorial experimental design framework for wood-bending research, and (2) the application of this framework to efficiently determine salient mechanical properties of E. regnans duringmicrowave bending and to determine the bending parameters required for optimum microwave bending of this species. Bending strains for compression parallel-to-grain, shear parallel-to-grain, and tension parallel-to-grain were investigated.The study revealed the following optimum microwave bending variables for E. regnans: moisture content above 70 percent, temperature in the range of 100°C to 105°C, and strain rates in the region of 0.1 mm/s or 137s.The study authenticated an optimum set of bending variables for the microwave heating of E. regnans that enabled minimum wood failure during bending operation.