A.1mm B.1.5mm C.2mm D.2.5mm
A.竖向受力B.横向受力C.侧向受力D.内部受力
A.0.25倍 B.0.35倍 C.0.45倍 D.0.55倍
A.3mm;7mm B.4mm;5mm C.4mm;7mm D.3mm;5mm
A.4% B.5% C.6% D.7%