E-E a是 E22}=0/×1 /x+。u2/x OU 8x4(丁 sowe br l2 eu The strain vedor can then be written as: A ouA/afi wnere 9认a 3 2 4x4 A=4|J2-00|and J00 -1JJ工 [6]{},!9+w*k ere ves Ms 4×88x1