Orientation Evaluation and Elastic Anisotropy of Polycrystalline Materials

In order to calculate the mechanical anisotropy of the stretched bulk polymer, we must take up to the 4th products of direction, cosine that derive the relations between the elastic compliance of the structural unit and those obtained in an arbitrary diτection in the speci-men, as the relations are given by 4th lank tensor.<BR>By using orientation distdbution obtained from X-ray diffraction of stretched polycrystall ine materials, Roe et al. proposed a method to evaluate the crystalline erientation distribution function with respect to the stretching direction. In this report, the Roe's method is further modified so as to evaluate the crystalline orientatien distribution function with respect to an arbitrary direction fxed in the specimen, and then to calculate the mechanical anisotropy of the specimen. Hence, by using a series of spherical harmonics, the average values of the 4th products of each direction cosine are evaluated by the averages of orientation distribution of the crystalline plane normal vectors obtained by X-ray diffraction measurement, and then, by using these results and the elastic compliance of structural unit, we describe the method to calculate the Young's modulus of the arbitrary direction in the specimen.<BR>Finally, as the determination of the structural unit plays an important part in the practical performance of the above described calculation, we proposed, for example, a structural unit model composed of crystalline and amorphous phases and produced by cennecting these phases in parallel or series to the three principal directions, and then the method to evaluate the elastic compliances of the structural unit in terms of its intrinsic moduli.