单项选择题
A.σr3=30MPa,σr4128MPa B.σr3=110MPa,σr4128MPa C.σr3=140MPa,σr4128MPa D.σr3=140MPa,σr4108MPa
A.i*>i0 B.与i*和i0之间的关系无关 C.i*=i0 D.i*<i0