Numerical Simulation Of Breadthwise Stretching Process Of Biaxially Oriented Plastics Film

When a biaxially oriented plastics film is breadthwise stretched, the distribution of the crystallizability affected by the temperature and stress will be the most important factor of the thickness distribution. It is certain that the asymmetrical distributing of crystallizability brings the asymmetrical distributing of filmy thickness.The temperature is a primary factor of crystallizability, and the action of stress can not be ignored also. The dissertation is to investigate the change of the PA66 film's stress distributing that different technics causes at the same temperature in the direction of thickness, and then study the effect that the distributing of the crystallizability caused by the special parameter of the material and the stretching technics. This dissertation is to simulate 1/2 geometry model of lengthways cross section using second-order Ogden constitutive model. ABAQUS software are used for the numerical simulation, and MATLAB software package is applied to deal with a great deal of data.It shows that temperature is the important factor affecting the crystallizability after choose a appropriate material, the closer up to the clamp, the smaller crystallizability is. At the same temperature, crystallizability of the film with greater stretching ratio is evener than crystallizability of the film with litter stretching ratio on the stretching orientation but asymmetrical on the towing orientation. At the same time, crystallizability will rapidly change when the stretching ratio is too small on the towing orientation. At the same temperature, crystallizability of the film with smaller stretching velocity is evener than crystallizability of the film with bigger stretching velocity on the towing orientation but asymmetrical on the stretching orientation. So we should choose an appropriate temperature and should make the temperature equably as we can. At the same time, we should choose appropriate stretching ratio and stretching velocity with a view to crystal effect that stress causes.The conclusion of this dissertation can optimize technics of biaxially oriented plastics film.