推荐回答(3个)
f —— 挠度,向下变位者为正,mm;
θ —— 转角,顺时针方向旋转者为正,°;
M —— 弯矩,使截面上部受压,下部受拉者为正,Nm;
Q —— 剪力,对邻近截面所产生的力矩沿顺时针方向者为正,N;
P —— 集中载荷,N;
q —— 均布载荷,N;
R —— 支座反力,作用方向向上者为正,N。
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扩展资料:
工字钢还可以采用特殊轧法:
(1)直轧孔型系统。直轧孔型系统是指工字钢孔型的两个开口腿同时处于轧辊轴线的同一侧,腰与轧辊轴线平行的孔型系统。
其优点是轧辊轴向力小,轴向窜动小,不需工作斜面,孔型占用辊身长度小,在辊身长度一定的条件下可多配孔型。
(2)斜轧孔型系统。这种孔型系统是指工字钢孔型的两个开口腿不同时处于腰部的同一侧,腰与水平轴线有一夹角。
参考资料来源:百度百科-工字钢
五、工字钢单位重量表
热轧普通工字钢每米重量表
型 号 尺寸(毫米) 截面面积
(厘米2) 理论重量
(公斤/米)
h b d t r1
10 100 68 4.5 7.6 3.3 14.3 11.2
12.6 126 74 5 8.4 3.5 18.1 14.2
14 140 80 5.5 9.1 3.8 21.5 16.9
16 160 88 6 9.9 4 26.1 20.5
18 180 94 6.5 10.7 4.3 30.6 24.1
20a 200 100 7 11.4 4.5 35.5 27.9
20b 200 102 9 11.4 4.5 39.5 31.1
22a 220 110 7.5 12.3 4.8 42 33
22b 220 112 9.5 12.3 4.8 46.4 36.4
25a 250 116 8 13 5 48.5 38.1
25b 250 118 10 13 5 53.5 42
28a 280 122 8.5 13.7 5.3 55.45 43.4
28b 280 124 10.5 13.7 5.3 61.05 47.9
32a 320 130 9.5 15 5.8 67.05 52.7
32b 320 132 11.5 15 5.8 73.45 57.7
32c 320 134 13.5 15 5.8 79.95 62.8
36a 360 136 10 15.8 6 76.3 59.9
36b 360 138 12 15.8 6 83.5 65.6
36c 360 140 14 15.8 6 90.7 71.2
40a 400 142 10.5 16.5 6.3 86.1 67.6
40b 400 144 12.5 16.5 6.3 94.1 73.8
40c 400 146 14.5 16.5 6.3 102 80.1
45a 450 150 11.5 18 6.8 102 80.4
45b 450 152 13.5 18 6.8 111 87.4
45c 450 154 15.5 18 6.8 120 94.5
50a 500 158 12 20 7 119 93.6
50b 500 160 14 20 7 129 101
50c 500 162 16 20 7 139 109
56a 560 166 12.5 21 7.3 135.25 106.2
56b 560 168 14.5 21 7.3 146.45 115
56c 560 170 16.5 21 7.3 157.85 123.9
63a 630 176 13 22 7.5 154.9 121.6
63b 630 178 15 22 7.5 167.5 131.5
63c 630 180 17 22 7.5 180.1 141
RA=RB=P/2
Mc=Mmax=Pl/4
fc=fmax=Pl^3/48EI
θA=θB=Pl^2/16EI
符号意义及单位
P —— 集中载荷,N;
q —— 均布载荷,N;
R —— 支座反力,作用方向向上者为正,N;
M —— 弯矩,使截面上部受压,下部受拉者为正,Nm;
Q —— 剪力,对邻近截面所产生的力矩沿顺时针方向者为正,N;
f —— 挠度,向下变位者为正,mm;
θ —— 转角,顺时针方向旋转者为正,°;
E —— 弹性模量,Gpa;
I —— 截面的轴惯性矩,m^4;
ξ=x/l,ζ=x'/l,α=a/l,β=b/l,γ=c/l
从两方面考虑:
第一,从梁的剪切应力考虑
第二,从弯曲正应力考虑。
从型钢表中可以查到它的最大可用剪切强度T
Tmax=Q/Ib[BH^2/8-<(B-b)h^2>/8]
式中: Tmax为最大剪切强度。把可用剪切强度T代进去,可算出梁的最大承受载荷。
Q为均布载荷
I为工字钢的截面惯矩可在型钢表中查得(cm^4).
B为工字钢截面的最大宽度。
b为工字钢截面的最小宽度
h为工字钢最小宽度截面的高度。
H为工字钢最大宽度截面的高度
正应力的计算:
Ysigma=M/W
M=最大弯矩=载荷乘距离
W=抗弯模量。
设Ysigma=允许的最大应力,可得出载荷的最大值。
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