The Study Of The Dimensional Stability Of Cornstalk Particle Prouducts In Die Compaction

The dimensional stability includes the thickness swelling and the line swelling, It restricts the production and the use of the goods of agriculture straw. Hygrodcopic expanding and internal strain are the main reasons those result in the dimensional stability. For the exist of moisture content gradient and thermal gradient, the thickness swelling is larger than the line swelling and so the thickness swelling is the emphasis of study.This paper studied the thickness swelling of corn particle in die compaction through rheologic performance. Firstly, established a die system and a data acquisition system. By orthogonal experiment and analysis of standard error confirmed the strain 5.6-7.0MPa, the temperature 120℃~170℃ and the moisture content 12%— 16%. Secondly, through the creep test studied the relation of the rheologic performance to the thickness swelling, and elected the linear and exponential strengthen constitutive equation, showed that the linear strengthen constitutive can accord with the process ofcompaction and can adjust the modulus of elasticity E and the modulus of viscosity ηthrough the strain and the moisture content. Finally, under the stand of the relative humidity changing, studied the course of variety of the thickness swelling, found out the main reason that reduces the thicking swelling is the hygrodcopic expanding.