??? ??? ???? ?? ??? ????? ?????? ?? ????? ??????????? ????? ?????? ??? He Xin ?? ????? ?? ????? ?????????? ?? ??????? ?????????? ?? ????? ???????? ????????? ?? ??????? ??????? ?? ???? ??????? ??????? ?????? ?????? ??????.

?????: ????? ???? ??? ??? ???? ?????? ????? ??? ?? ????? ?????? ????? ????????

?????? ??? ??? ???? ?????? ????? ??...??? ????? ?????? (?????? ????? ???? ??? ??? ??????)——???? ??? ???? ????? ????? ?????? ?? ??????? ??? ????? ??? ????? ??? ?????? ??????? ??????? ??????? ?????? ?? ????? ??? ????? ????? (tf) ?? ??????? ????? (kN). ??? ???? ???? ?? ??? ???? ??? ???? ?????? ??? ????? ??? ???? ??? ????? ?? ??.

??????? ????? ??????	??????? ????? ??????
??? ????? ??? ????? ???? ???? ?????? ???????? ??? ???? ??? ???? ???? ????? ?????? ??????? ???????	?????? ?????? ??????? ???????? ???????? ??????
????????? ??????? ????? ?????? ??? ???????? ??????? ????? ????????	"??????? ??? ????? ?????? ????? ????"? ??? ???? ??? ??? ???? ????? ?????? ?????? ?????????
??????? ??? ????? ???????? ??? ???? ????? ??? ???????	??? ?? ?????? ??????? ??? ????? ?????? ????? ??? ??????? ???????? ??? ??????? ?? ??? ?????

??????: ?? ?? ??? ????? ?????? (??? ??? ??????)?

??? ????? ?????? ?? ???? ??? ???? ?? ??????? ??? ????? ?? ?????? ??? ?????? ?????? ??? ???? ??????. ??? ?????? ??? ??? ???? ?????? ?????? ??? ?????? ?? ???:??? ????? ?????? ??????? / ??? ????? ?????? ???????? ????? ?? ?????? ????? ?????? ???????? ??? ?????? ???????? ????? ????????? ??????. ?????? ???????? ??? ?? ???? ??????? ???????? ???????? ??? ?? ??? ????? ?????? ??????? ????? ?? ??? ???? ????.

??????: ??? ????? ????? ???????? ??? ???? ??????? ??????? ?? ?? ?? ??????? ??????? ?????????

????? ??????? ???? ??????? ??? ???? ??? ????????? ???????? ??????? ??? ??????? ???? ??????? ??? ??? ?????. ???? ?? ????? ?? ?????? ?? ??????? ??? ??? ?????? ???????? ????? ??? ???? ??? ?????? ??? ?? ????? ??? ????? ???? ??? ???? ???? ?? ???????. ??? ??? ??????? ??????? ??????? ?? ???????:

• ??? ?????? ????????: ????? ???? ??????? ?????? ??? ??? ??????
• ???? ????: ????? ??????? ?????? ???????? ??????? ????????
• ???? ??????? / ???? ????? ??????: ??????? ??????? ???? ?????? ???? ????? ????????
• ???? ??????: ??????? ??????? ????? ?????? / ????? ????? ??????.

??????? ????????? ??????? ?????? ????? ??????? = ????? ?????? ???????? + ????? ???? ???? + ????? ??????. ??? ??????? ?????? ????? ?????????? ?????? ??? ????? ?? ??? ??????? ??????:

????? ??????? ?? ???? ?????? A = (????? ?????? ???????? + ????? ???? ???? + ????? ??????) × ??? ?????? ??????

????????? ????????:??? ???? ??????? ??????? ???? ??????? ????? ???? ????? ??? ???? ??????? 30%–40% ??????? ??? ?? ??? ??????? ???? ?? ??? ??????? ???? ??? ???? ????? ???? ?????? ????? ??????.

??????: ??? ??? ????? ??? ?????? ?????? ??? ?????? ??? ??? ???????

????? ?????? ????? ??????? ????? ??????? (MPa? 1 MPa = 1 N/mm2) ???? ?????? ???? ????? ??? ?????? ??????. ???? ????? ????? ??????? ???? ????? ???????? ???? ???? ????? ??? ????? ?????? ????????. ?????? ??? ????? ?????? ???? ????? ????? ????? ???????????????? ?? ????????????? ???? ??? ???????? ??????:

??? ???????	???? ????? ?????? ?????? ?? ????? (???? ??????)	??????? ?????????
????? ?????	20 – 40	??????? ??????? ???????? ???????? ????? ????? ??? 30 ???????
??????????	30 – 80	?????? ????? ????? ??? 30 ?50 ??????? ???????? ??????? ???? 60 ?80 ??????? ??????? ????? ??????/??????? ????? ???????
????? ??????????	30 – 70	??????? ???????? ??? ??????? ??????? ???????? ?????
????? ????	40 – 80	????? ?????? ???????? ??? ?????

??? ???????????? ??? ??? ?????? ???? ???? ??????? ????? ???? ??????? ???? ????? ?????? ?????? ?????? ???? ??????? ?????? ???????? ?????? ????? ?????? ???? ??????? ???? ??? ????? ?? ????? ???? ??? ????? ????.

??????? ??? ???? ???????? ?? ????? ??????????? ???? ?????? ?? ??? ????? ?? ????? ??????? ???? ???? ?? ?????? ???????? ??? ?????? ????? ??????? ? ???? ???? ?????? ? ????? ?? ?????????? ???????? ?????? ??????? ???????? ?? ????? ??????

??????: ??? ??? ????? ????? ?????? K?

??????? ????? ?????? ?????? ?????? ??? ????? ??????? ?????? ????? ??????? ????????? ???????? ???????. ????? ?????? ???:

• ??????? ???????? ???????: ??? 1.1 – 1.2；
• ??????? ???????? ??????? ??? ???? ????? ?????: ??? 1.2 – 1.3.

??????: ???? ???? ??? ??? ???? ?????? ?????? ???????

??? ????? ?????? F (kN) = ????? ?????? ????? P (MPa) × ??????? ????????? ??????? ??????? A (mm2) × ????? ?????? K

????? ??? 1 ???? ?????? = 1 ?????/??2? ??? ??? ??? ????? ?????? ???? ???? ??????? ????? ???????? (N)? ?? ??? ??????? ??? ??:

??????	?????? ???????	?????????
1 ?? ??? (tf)	≈ 10 ???? ?????	??????? ??? ??????? ???? ???? ?? ???????? ??? ????? 1 tf ≈ 9.8 ???? ?????
1 ???? ??????	= 1 ?????/??2	???? ??? ????? ?????? ???????? ???????

??? ???? ????????????? ??????? ??? ???? ??? ???????? ??? ??????? ????????. ???? ????? ?????? ??????? ????? ???? ?????? 88? ?125? ?160? ?200? ?280? ?400? ?630? ?800? ?1000? ?1250? ?1600? ?2000? ?2500? ?3000 ??? ??????.

7. ????? ?????: ????? ???????? ???? ?????

???? ??????? ??????? ????? ??????? ??????? ????? ???????? ??????? ?? ????????? ??? ??? ?????? ??? ??????? ?????? ?????? ???? ??????? ??? ???? ???? ???? ????? ?? ????? ?????????? ?????? ???????? ????? ????? ??????? ???????? ????????.

?????? 1 · ???? ?????? ????? ?? ????? ??????????

• ????? ??????? ??????? ?????? ???????? 200 ?? × 150 ?? → ????? ?????? ???????? = 30 000 ??2?
• ????? ??? ???? 30% ??????? ?? ???? ????? ????? ???????? ???? ?????? → ???? ????? ??????? ???? ?????? A = 30 000 × 1.3 ≈ 39 000 ??2?
• ??????? ??????? ???????? ???????? ????? ??? ????? P = 40 ???? ???????
• ????? ????? ?????? K = 1.2?
• ??? ????? ?????? ???????? F = 40 × 39 000 × 1.2 = 1 872 000 ????? ≈ 1872 ???? ????? ≈ 187 ????；
• ???????? ??? ?????? ??????? → ???????? ??? ???? ?????? 250T / 280T.

?????? 2 · ???? ?????? ?? ????? ????? ??? ????? ??????

• ???? ????? ?? ????? ?? ???? ???? 100 × 80 = 8000 ??2? ?? ?????? ???? ???? 30% ??? ????? → 10400 ??2 ??? ??????
• ??????? ????????? ????? ????? ??????? A = 10 400 × 4 = 41 600 ??2?
• ??????? ???????? ???????? ?? ????? ?????? ?? ??? ??? ????? ?????? P = 30 ???? ???????
• ????? ????? ?????? K = 1.2?
• ??? ????? ?????? ???????? F = 30 × 41 600 × 1.2 = 1 497 600 ????? ≈ 1498 ???? ????? ≈ 150 ????；
• ???????? ??? ?????? ??????? → ???????? ??? ???? ?????? 160T.

??????: ???? ??????? ??? ?????? ??? ??? ???? ??????: 4 ????? ?????

• ????? ?????? ??? 1: ?????? ????? ???????? ??? ??? ?????? ???? ???? ?????? → ??????? ??? ????? ?? ???????. ??? ?????? ?? ????? ????? ????? ?????? ???????? ???? ?????? ??????? ?? ????? ??????? ?????? ????? ??????.
• ???????? ?????? ??? 2: ?????? "???? ??? ????? ??????" ???? ?????? → ??? ?????? ?????? ????? ???? ????? ?????? ????????/???????? ?? ??? ???? ????.
• ???????? ?????? ??? 3: ????? ????? ?????? K → ????? ????? ?????? ??????? ?? ???? ??????? ???? ?? ????? ????? ???? ?????? ?? ??????? ??? ??? ???????? ????? ???? ????.
• ????? ?????? ??? 4: ????? ??? ??? ?????? ?????? ?? ??? ?????? ?????? → ??? ?????? ???????? ????? ??"??????? ????????? ??? ????? × ??? ????????"? ?? ???? ?????? ????? ???? ???.

??????: ??????? ??????? (FAQ) ??? ??? ???? ???? ??????

?? ?? ??????? ??? ??? ??? ???? ?????? ???? ???? ?????

?? ???? ????? ???? ??????. ?? ???? ????? ???????? ?? ????? ??????? ????? ????? ?? ????? ?????? ???? ?????. ??? ??? ???????? ????? ????? ???????? ??? ????? ?????????? ?????? ????? ??????? ???? ????? ?? ????? ?????.

?? ?? ???? ?????? ?????? ????? ???? ???? ??????? ??????? ????? ?????

?????????? ?????? ?? ??????: ????? ??????? ≤ ??????? ??????? ÷ (??? ????? × ????? ?????? K). ??? ???? ??????? ??? ??????? 280 ???? ?? 40 ???? ?????? ?K=1.2? ???? ????? ??????? ????? 58000 ??2? ???? ?????? ?? ??? ??????? ??? ????? ????? ?????? ??????.

?? ?? ?????? ???????? ??? ?????? ??? ??? ???? ?????? ???? ?? ???????

?????? ?????? ??????? ???????? ???????? ??????? ??????? ????? ??????? ?????? ???????. ????? ??????? ????? ?????? ??????? ????? ?????????? ???????? ??? ?????? ??? ????? ?????? ???? ????? ??????.

?? ????? ?? ?????? ???? ???? ?????? ?????? ?????????? ?????? ??????

????? ????????? ???? ??? ????? (30–80 ???? ??????)? ?? ??? ?? ????? ??? ????? ????? ??????? (20–40 ???? ??????). ????? ?????? ??? ?????? ????? ????? ???????? ???? ???? ?????? ???? ????? ??? ??? ??????? ???????.

???? ???? ??? ?? ??? ??? ????? ?????? ??????? ????? ??? ?????? ????????

????? ????? ???????? ?????? ?????? ?????? ????? ??????? ????? ???? ????? ??????. ????? ???? ???? ???? 10%–20% ????? ?????? ???????? ?????? ??? ???? ?????? ??????? ????? ?????? ????????.

??????? ?????: ????? ??????? ???? ??? ???? ?????? ?????? ??????? ?? ????? ??????

• ??? ?????? ??????? ???????? ???? ?????? ???? ????: ?????? ???????? + ???? ???? + ???? ??????? + ??? ??????? ?? ??? ??? ???????? ?? ??? ?????? ???????
• ??? ????? ??? ????? ?????? ??????? ??? ??????? ?????? ????????? ?? ??? ???? ?????? ?? ???????? ??????? ??????? ??????? ????? ??????/????? ????????
• ?? ???? ??????? ????? ?????? K (1.1–1.3)?
• ??? ????? ??????? ???????? ??? ???? ???? ????? ?????? ???????? ?? ??? ???? ?????? ??? 10% ?20%.

??? ??? ??????? ??????? ????? ?????? ?????? ????????? ??? ???????? ?????? ??????? ??????? ?? ????? ??????? ??????? ??? ??????? ???????? ??? ??? ????? ?????? ???? ????? ???? ??????? ???????. ??? ?? ?????? ????? ?? ??? ??????? ???????? ??? ????? ???????? ????? ????? ?? ????? ?????? ?????? ??????? ??? ????? ?? ????? ?? ?????? ??? ??? ???? ??????.

?? ????? ??? ?????? ?? ??? ?????? ?????? ????? ?????? ????? ???????? ???? ????? ?? ????? ????? ??????? ???? ?????? ??????? ????????? ?????? ?????? ?????? ??????????. ???? ?????? ?????? ?????? ?????? ??? ????? ???? ?????? ?????? ????? ????????.