1、正正三三角角形形截截面面性性質質計計算算 b2 20 0(mm)正三角形邊長 b h1 17 7. .3 32 2(mm)正三角形高 h=b*sin(Pi/3) A1 17 73 3. .2 21 1(mm)截面面積 A=b*h/2 Ix2 2. .8 88 86 68 8E E+ +0 03 3 (mm4)慣性矩 Ix=b*h3/36 Ix08 8. .6 66 60 03 3E E+ +0 03 3 (mm4)截面對下邊緣慣性矩 Ix0=Ix+(b*h/2)*(h/3)2 Iy2 2. .8 88 86 68 8E E+ +0 03 3 (mm4)慣性矩 Iy=2*(h*(b/2)3/36
2、+(b*h/4)*(b/6)2) ix4.0825E+00 (mm)回轉半徑 ix=sqrt(Ix/A) ix07.0711E+00 (mm)截面對下邊緣回轉半徑 ix0=sqrt(Ix0/A) iy4.0825E+00 (mm)回轉半徑 iy=sqrt(Iy/A) Wx2 2. .5 50 00 00 0E E+ +0 02 2 (mm3)截面抵抗矩 Wx=Ix/(h*2/3) Wx05 5. .0 00 00 00 0E E+ +0 02 2 (mm3)截面抵抗矩 Wx0=Ix/(h/3) Wy2 2. .8 88 86 68 8E E+ +0 02 2 (mm3)截面抵抗矩 Wy=Iy/(b/2) =7 78 8. .5 5(kN/m3) 材料重度 (鋼材為78.5kN/m3) G0 0. .0 01 13 36 6(kN/m) 每延米自重 G=A