1、TSINGHUA UNIVERSITYTSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY 返回總目錄返回總目錄TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSI

2、TY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY 分布力

3、：連續(xù)作用于構(gòu)件表面的力。集中力：作用面積極小的分布力。面力按載荷隨時(shí)間變化情況1.靜載荷 2.動(dòng)載荷TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY 梁拉桿TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY 截面法用假設(shè)平面將構(gòu)件截開(kāi)從而揭示構(gòu)件內(nèi)力并確定內(nèi)力的方法。截：用假設(shè)平面將構(gòu)件在欲求內(nèi)力處截開(kāi)。棄：保留研究部分，棄去其它部分。代：以截面上的內(nèi)力代替被棄部分對(duì)保留部分的作用。平：建立保留部分的平衡方程，確定未知內(nèi)力。TSINGHUA UNIVERSITY F1F3F2FnBAF1F2F3

4、FnABTSINGHUA UNIVERSITYF1FRF3MF1F3 TSINGHUA UNIVERSITYFRFNFQMMBMx TSINGHUA UNIVERSITY 在一定條件下，桿件所有內(nèi)力分量作用的效果，可以視為各個(gè)內(nèi)力分量單獨(dú)作用效果的疊加。通?？蓺w結(jié)為三組平面內(nèi)內(nèi)力分量與外力：yxzFP1 FP2FRMMzMyMxFQ yFQ zFNFQ TSINGHUA UNIVERSITYyxzMxyxzFQ zFNMyyxzFQ yFNMz TSINGHUA UNIVERSITY FAyFByTSINGHUA UNIVERSITY FAyFByTSINGHUA UNIVERSITY TSI

5、NGHUA UNIVERSITY TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITYTSINGHUA UNIVERSITYF1F3F2FnF1F2F3FnTSINGHUA UNIVERSITYTSINGHUA UNIVERSITYFN=FFFFFFFFTSINGHUA UNIVERSITYM M0M0M0M0M0M0M0M0TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTSINGHUA UNIVERSIT

6、Y 內(nèi)力的集度或單位面積上內(nèi)力的大小。TSINGHUA UNIVERSITY TSINGHUA UNIVERSITYyxzAFAlimN0 AFAlimQ0 AFQyFQzFNDFRFP1FP2TSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTSINGHUA UNIVERSITYFP1FP2yxzdAxMyFN xMzxAxFANdyAxMzAdzAxMyAdTSINGHUA UNIVERSITYFP1FP2yxzdAxyxzyAxyFAQdAxyzAdzAxzFAQdxAxzMyAdTSINGHUA UNIVERSITYTSINGHUA UNIVERSITY返回返

7、回 返回總目錄返回總目錄TSINGHUA UNIVERSITY TSINGHUA UNIVERSITYTSINGHUA UNIVERSITYxu+duxxxuxdddxxu 單元體的兩條相互垂直的棱邊，在變形后的直角改變量。長(zhǎng)度在變形前后的改變量與原長(zhǎng)之比。TSINGHUA UNIVERSITYTSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITYEExxxx,GG,OxxO TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA U

8、NIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY TSINGHUA UNIVERSITY返回返回 返回總目錄返回總目錄TSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTSINGHUA UNIVERSITYTS