材料力学_华南理工大学出版社_习题答案
- 格式:doc
- 大小:561.50 KB
- 文档页数:6
材料力学习题部分答案
2-1 (a) N 1=-20KN (b) N 1=P; N 2=2P 2-2 max σ=150a MP 2-3 BC σ=76.4a MP 2-4 σ=31.9a MP 2-5 G=37.1 KN 2-6 a ≥69mm
2-8 d ≤18mm ; A ≥8332
mm ; P ≤15.7KN 2-10 E=204a GP ; μ=0.317
2-11
[ P ]=21.6KN
2-14 α=26.560; [ P ]=50KN 2-15 总l ∆=-0.017mm
2-16 σ=158.4a MP ; BV ∆=7.2mm 2-17 x=0.6m ; P ≤200KN 2-21 A ≥22.60cm 2
2-22 AB σ=108.3a MP ; BC σ=8.3a MP ; CD σ=-141.7a MP 2-24 铜杆σ1=225a MP ; 钢杆σ2
=375a MP ; ∆L 2=3.75mm
2-25 σ=-100.7a MP ;
3-3 d=33mm ; τ=70.7a MP 3-4 τ=15.9a MP 3-5 jy
σ
=134.7a MP
3-6 [P]=176.7N ; τ=17.6a MP 3-7 τ=136.8a MP ; jy
σ
=171.0a MP ; 1σ=2σ=171.9a MP
3-8 l =406mm
4-1 (a) -43; -88 ; +91; +54 (单位: N •m)
4-2 max 1τ=78.5a MP ; max 2τ=43.3a MP ; max 3τ=82.5a MP 4-3 max 1τ=191.7a MP max 2τ=158.8a MP τm ax =191.7
a MP
4-7 1.44倍和2.33倍
4-8 d=48.5mm ; d 2=57.8mm 4-9 d=21.6mm ; [ Q ]=1.12KN
4-10 max 1τ=49.4a MP ; max 1θ=1.770/m ; max 3τ=21.3a MP ; max 2θ=0.440/m (注:3N 由3KW 改为30KW ) 4-11 D=63mm
4-12 d 1=84.6mm ; d 2=74.5mm ; d=85.0mm ; 主动轮安排在中间
4-14 ϕ=ρ
GI tl 22
4-18 τm ax =62.2
a MP ; λ=115mm
5-1 (a) Z S =
32
2
3t b t + 5-2 (a) c y =119.3mm ; (b) c y =146.7mm ; c z =80mm ; (c); c y =115.7mm ; c z =0.9mm 5-3 z I =
16π4R ; yz I =8
14R 5-4
(a) y I =z I =2.23×5104mm yz I =7.75×4104mm
(b) z I =3
3
1bh y I =331hb yz I =-422h b
5-5 (a) zc I =3.57×8104
mm
5-8 0α=05.76(对应于0y ); 0z I =7.606×5104mm ; 0y I =1.994×5104
mm
6-1 (g) 1Q =-1.67KN ;1M =5 KN ; (l) 1Q =30 KN ;1M =-45 KN ;2Q =0;2M =-40 KN 6-2 (c) A Q =2qa ; B Q =C Q =0; A M =-q 2
a ; B M =C M =q 2
a
(k) C Q =-qa ; A Q =B Q =0; A M =0; B M =-
21q 2a ; C M =-q 2a 6-4 (h) A Q =0; B Q =C Q =-qa ; A M =q 2a ; B M =21q 2
a ; C M =-2
1q 2a
(m) A Q =0; B Q =-qa ; C Q =qa ;0; A M =0; B M =0; C M =2
1q 2
a
(t) A Q =C Q =61qa ; B Q =D Q =-65qa ; A M =B M =0; C M =61q 2a 左D M =-61q 2a ; 右D M =6
5
q 2a
6-6 l
a
=0.207
7-1 σ=352a MP 7-2 σ=105a MP 7-3 D=2
.0σd
E
7-4 除纵向线应变不同外,其余相同。
7-6 (a) A σ=D σ=-163a MP ; B σ=39a MP ; C σ=58.8a MP
(b) A σ=-D σ=-18.5a MP ; B σ=C σ=0
7-7 截面Ⅰ: A σ=-7.41a MP ; B σ=4.95a MP ; C σ=0; D σ=7.41a MP ;
截面Ⅱ: A σ=9.26a MP ; B σ=-6.17a MP ; C σ=0; D σ=-9.26a MP ; 7-8 max σ=40.92a MP
7-9 容许弯矩之比: 2:1 抗弯刚度之比: 4:1 7-10 (1) (b)的最大正应力大于(a)的最大正应力
(2) Zb W =9.43×410-3m ; Zc W =9.87×410-3
m ; Zc Zb W W <
(3) u=15.7mm ; 5.35% 7-11 P=35.5KN
7-12 2
3
2Ebh ql l =∆
7-16 max σ=153.8a MP 7-17 max σ=153.4a MP 7-19 h=185mm ; b=62mm 7-20 b
h
=2; d=227mm 7-21 d=114.7mm
7-22
t n =5.4, e n =15.0
7-23 ≤l 32.1m 7-24 a=1.385m
7-25 a=2.12m ; q=25KN/m