瓯 (Axial tension& Compression, Shear)□ 求BC段内的轴力 RAl 40k 55kN 25k 120KN B E 40kN FN,-FD-40=0 N2 RA FN2=FRA+40=+50(kN)(+)
16 (Axial tension & Compression, Shear) 求BC段内的轴力 FRA 40kN FN2 20kN A B C D E 40kN 55kN 25kN FRA 2 40 0 FN2 − FRA − = 40 50(kN) ( ) FN2 = FRA + = + +
瓯 (Axial tension& Compression, Shear)□ 求CD段内的轴方 RAl 40KN 55kN 25k 20kN B D E -FN1-25+20=0 3|25kN 20KN N3 5(kN)(-)
17 (Axial tension & Compression, Shear) FN3 求CD段内的轴力 25kN 20kN A B C D E 40kN 55kN 25kN 20kN FRA 3 − FN3 − 25 + 20 = 0 5(kN) ( ) FN3 = − −
瓯 (Axial tension& Compression, Shear)□ 求DE段内的轴力 40KN 55kN 25KN 20KN FN4=+20(kN)(+) 20kN
18 (Axial tension & Compression, Shear) 求DE段内的轴力 F 20kN N4 40kN 55kN 25kN 20kN FRA 4 20(kN) ( ) FN4 = + +
瓯 (Axial tension& Compression, Shear)□ 40KN 55KN 25KN 20KN B E 600 300 500 400 FN1=10kN(拉力) 50 FN2=50kN(拉力) 5kN(压力) 20 10 FN4=20kN(拉力 ∏ FNmx=50(kN)发生在BC段内任一横截面上
19 (Axial tension & Compression, Shear) FN1=10kN （拉力） FN2=50kN （拉力） FN3= - 5kN （压力） FN4=20kN （拉力） 发生在BC段内任一横截面上 50 10 5 20 + + A B C D 600 300 500 400 E 40kN 55kN 25kN 20kN 50(kN) FNmax =
瓯 (Axial tension& Compression, Shear)□ §2-3应力及强度条件 (Stress and strength condition) 、横截面上的正应力( Normal stress on cross section F F F b d
20 (Axial tension & Compression, Shear) §2-3 应力及强度条件 (Stress and strength condition) 一、横截面上的正应力(Normal stress on cross section) F F a b c d