Tensor components of stress

The components of stress have already been defined in Section 2.1 in terms of the equilibrium of a cube and these form the elements of a symmetric second-rank tensor 

An Introduction to the Mechanical Properties of Solid Polymers I. M. Ward and J. Sweeney 2004 John Wiley Sons, Ltd ISBN 0471 49625 1 (HB) 0471 49626 X (PB) 

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The most general linear relationship between stress and strain is obtained by assuming that each of the tensor components of stress is linearly related to all the tensor components of strain and vice versa. Thus... 

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