``Practical'' components of vectors and tensors (Q1085650)

The author is concerned with the ''practical components'' for two- and three-dimensional vectors and tensors. The practical components of a vector are defined as those with respect to an anholonomic reference frame, whose base vectors are oriented as required. The practical components of a second order tensor are given from those of the vectors; for example, the practical components of the stress tensor are given in relation with those of the force vector and the surface vector through the well-known relation. The author gives as example the practical components of the stress tensor on the middle surface of a shell, where an anholonomic reference frame is taken so that its axes are oriented to the directions of the principal stress. The trigonometric terms are used to advantage.