Effect of temperature on the spring back of cellulose-based sheet in hot pressing

The present study aimed at investigating the effect of temperature on the spring back of cellulose-based sheets in hot pressing through experimental and numerical analysis. Thus, hot pressing process was applied to form cellulose-based sheet into a ring with U-shape cross section. Mechanical properties of the sheets under different time, temperature, and moisture-content conditions were obtained using experimental tests. Based on viscoelastic model, the hot pressing of cellulose-based sheets was successfully simulated using the data obtained from the material tests. The spring back of the parts during a time span of 10,000 s after opening of the die was obtained based on experimental tests and finite element simulation. The effects of temperature of the process and stress relaxation on the spring back were also investigated and the material behavior was also discussed. Simulation results conformed to the experiments, indicating that the approach is capable of accurately predicting the spring back of cellulose-based sheets in hot pressing.