Numerical and Experimental analysis of cellulose sheet Hot-pressing

The manufacturing process of cellulose ring which isused widely as electrical insulator in power transformator is studied in this paper. The primary sheet is mainly consists of natural random cellulose fibers. Manufacturing process begins by moisturizing the sheet and subsequently the sheet becomes a ring by hotpressing. After removing the part from die, due to spring back, the radius of the part increases and this phenomenon could be used to manufacture parts with various radiuses by one die. In this study, experimental tests and measuring the radius of part were carried out with regard to the affecting parameters such as temperature and time of the part maintenance in the die. Also mechanical properties of cellulose sheet in the influence of time, temperature and moisture content was investigated. The hot-pressing has been simulated and the ring radius estimated numerically using the finite element method (FEM). Comparisons of experimental and numerical results indicate that the numerical approach can accurately predict the spring back in this process.

کلیدواژه ها:

FEM ، Viscoelasticity ، hot-pressing ، cellulose ، spring back