m squared upper V 1 plus n squared upper V 2 right-parenthesis upper Delta upper T comma 3rd Row epsilon prime Subscript 22 Baseline equals left-parenthesis n squared upper S 11 plus m squared upper S 12 right-parenthesis sigma 11 plus left-parenthesis n squared upper S 12 plus m squared upper S 22 right-parenthesis sigma 22 plus left-parenthesis n squared upper S 13 plus m squared upper S 23 right-parenthesis sigma 33 4th Row minus m n upper S 66 sigma 12 plus left-parenthesis n squared upper V 1 plus m squared upper V 2 right-parenthesis upper Delta upper T comma 5th Row epsilon prime Subscript 33 Baseline equals upper S 13 sigma 11 plus upper S 23 sigma 22 plus upper S 33 sigma 33 plus upper V 3 upper Delta upper T comma 6th Row epsilon prime Subscript 23 Baseline equals one-half m upper S 44 sigma 23 minus one-half n upper S 55 sigma 13 equals epsilon prime Subscript 32 Baseline comma 7th Row epsilon prime Subscript 13 Baseline equals one-half n upper S 44 sigma 23 plus one-half m upper S 55 sigma 13 equals epsilon prime Subscript 31 Baseline comma 8th Row epsilon prime Subscript 12 Baseline equals m n left-bracket left-parenthesis upper S 12 minus upper S 11 right-parenthesis sigma 11 plus left-parenthesis upper S 22 minus upper S 12 right-parenthesis sigma 22 plus left-parenthesis upper S 23 minus upper S 13 right-parenthesis sigma 33 right-bracket 9th Row plus one-half left-parenthesis m squared minus n squared right-parenthesis upper S 66 sigma 12 minus m n left-parenthesis upper V 1 minus upper V 2 right-parenthesis upper Delta upper T equals epsilon prime Subscript 21 Baseline period EndLayout"/>(2.182)
Substitution of (2.178) into (2.182) leads to the relations
(2.183)
where
(2.184)
(2.185)
(2.186)
and where
(2.187)
2.17.1 Transverse Isotropic and Isotropic Solids
When considering unidirectionally reinforced fibre composites, as will be the case in Chapter 4, the effective composite properties are often assumed to be isotropic in the plane that is normal to the fibre direction taken here to be the x3-direction as coordinate rotations considered previously have been about the x3-axis. It is now assumed that S11=S22, S44=S55 and S13=S23. As m2 + n2 = 1 and
it then follows from (2.184)–(2.186) that