中国石油大学(北京)现代远程教育《工程力学》期末考试答案

中国石油大学(北京)远程教育学院期末考试《工程力学》学习中心:____姓名:___学号:____关于课程考试违规作弊的说明1、提交文件中涉嫌抄袭内容(包括抄袭网上、书籍、报刊杂志及其她已有论文),带有明显外校标记,不符合学院要求或学生本人情况,或存在查明出处的内容或其她可疑字样者,判为抄袭,成绩为“0”。

2、两人或两人以上答题内容或用语有50%以上相同者判为雷同,成绩为“0”。

3、所提交试卷或材料没有对老师题目进行作答或提交内容与该课程要求完全不相干者,认定为“白卷”或“错卷”,成绩为“0”。

一、题型简答题,8题,每题5分,共40;计算题,4题,每题15分,共60分)二、题目学号尾数为奇数的同学做题目序号后有“A”字样的题,学号尾数为偶数的同学做题目序号后有“B”字样的题简答题:1A 在铸铁压缩试验中,破坏后的铸铁试样断口平滑呈韧性,与轴线近似成45°。

破坏前,该断口所在斜截面的应力有何特点？答:剪应力最大1B 在铸铁扭转试验中,铸铁断口的形态就是什么样的？答:断口呈螺旋面、与轴线近似成45°。

2A 根据铸铁试件扭转破坏断口可以推断,铸铁的扭转破坏与什么因素有很大的关系？ 答:最大拉应力2B 电阻应变片(简称电阻片或应变片)应用广泛,它就是利用什么原理实现电测的？ 答:金属丝的电阻随机械变形而发生变化 3A 冲击韧性的物理意义就是什么？ 答:试样断裂过程中断面单位面积吸收的能量 3B 矩形截面梁在截面B 处沿铅垂对称轴与水平对称轴方向上分别作用有P F ,如图所示。

请问最大拉应力与最大压应力发生在危险截面A 的哪些点上？答:4A 构件中危险点的应力状态如图所示。

构件为钢制:x σ=45MPa,y σ=135MPa,z σ=0,xy τ=0,许用应力[]σ=160MPa 。

请用第三强度理论校核该构件的强度。

答:选用第三强度理论,构件满足强度要求4B 构件中危险点的应力状态如图所示。

中国石油大学(北京)《工程力学》期末考试答案37567中国石油大学（北京）远程教育学院期末考试《工程力学》学习中心：____姓名：___学号：____ 关于课程考试违规作弊的说明1、提交文件中涉嫌抄袭内容（包括抄袭网上、书籍、报刊杂志及其他已有论文），带有明显外校标记，不符合学院要求或学生本人情况，或存在查明出处的内容或其他可疑字样者，判为抄袭，成绩为“0”。

2、两人或两人以上答题内容或用语有50%以上相同者判为雷同，成绩为“0”。

3、所提交试卷或材料没有对老师题目进行作答或提交内容与该课程要求完全不相干者，认定为“白卷”或“错卷”，成绩为“0”。

一、题型简答题，8题，每题5分，共40；计算题，4题，每题15分，共60分）二、题目学号尾数为奇数的同学做题目序号后有“A”字样的题，学号尾数为偶数的同学做题目序号后有“B”字样的题简答题：1A 在铸铁压缩试验中，破坏后的铸铁试样断口平滑呈韧性，与轴线近似成45°。

破坏前，该断口所在斜截面的应力有何特点？答：剪应力最大1B 在铸铁扭转试验中，铸铁断口的形态是什么样的？答：断口呈螺旋面、与轴线近似成45°。

2A 根据铸铁试件扭转破坏断口可以推断，铸铁的扭转破坏和什么因素有很大的关系？答：最大拉应力2B 电阻应变片（简称电阻片或应变片）应用广泛，它是利用什么原理实现电测的？答：金属丝的电阻随机械变形而发生变化 3A 冲击韧性的物理意义是什么？答：试样断裂过程中断面单位面积吸收的能量3B 矩形截面梁在截面B处沿铅垂对称轴和水平对称轴方向上分别作用有，如图所示。

请问最大拉应力和最大压应力发生在危险截面A的哪些点上？答：4A 构件中危险点的应力状态如图所示。

构件为钢制：=45MPa，=135MPa，=0，=0，许用应力=160MPa。

请用第三强度理论校核该构件的强度。

答：选用第三强度理论，构件满足强度要求4B 构件中危险点的应力状态如图所示。

《工程力学》课程综合复习资料
一、计算题
1. 已知：受力构件内某点的原始单元体应力如图示。

单位：MPa。

求：指定斜面AB上的应力。

2. 已知：简支梁AB，中点C 处有集中力P，AC段有均匀分布力q，DB段有线性分布力，其最大值为q。

求：A、B两处的约束反力。

（先画出受力图）
3. 已知：静不定梁AB，分布载荷q、长度4a，横截面抗弯刚度EIZ 。

求：支座B的反力。

提示：首先选定多于约束，并画出相当系统，列出几何条件。

4. 图示铣刀C的直径D = 9 cm，切削力PZ = 2.2 kN，圆截面刀杆AB长L= 32 cm，许用应力[] = 80 MPa，Me为绕x轴外力偶矩，AB处于平衡状态。

试用第三强度理论，求刀杆AB的直径d。

提示：首先把P Z力向C点平移，明确指出组合变形种类。

工程力学第1页共9页。

中国石油大学（北京）远程教育学院期末考试《工程力学》学习中心：石家庄桥西奥鹏学习中心姓名：姚军_学号：959048关于课程考试违规作弊的说明1、提交文件中涉嫌抄袭内容（包括抄袭网上、书籍、报刊杂志及其他已有论文），带有明显外校标记，不符合学院要求或学生本人情况，或存在查明出处的内容或其他可疑字样者，判为抄袭，成绩为“0”。

2、两人或两人以上答题内容或用语有50%以上相同者判为雷同，成绩为“0”。

3、所提交试卷或材料没有对老师题目进行作答或提交内容与该课程要求完全不相干者，认定为“白卷”或“错卷”，成绩为“0”。

一、题型简答题，8题，每题5分，共40；计算题，4题，每题15分，共60分）二、题目学号尾数为奇数的同学做题目序号后有“A”字样的题，学号尾数为偶数的同学做题目序号后有“B”字样的题简答题：1A 在铸铁压缩试验中，破坏后的铸铁试样断口平滑呈韧性，与轴线近似成45°。

破坏前，该断口所在斜截面的应力有何特点？1B 在铸铁扭转试验中，铸铁断口的形态是什么样的？答：断口呈现螺旋面，与轴线近似45°斜截面破坏，2A 根据铸铁试件扭转破坏断口可以推断，铸铁的扭转破坏和什么因素有很大的关系？2B 电阻应变片（简称电阻片或应变片）应用广泛，它是利用什么原理实现电测的？答：金属丝的电阻随机械变形而发生变化。

3A 冲击韧性的物理意义是什么？3B 矩形截面梁在截面B处沿铅垂对称轴和水平F，如图所示。

请对称轴方向上分别作用有P问最大拉应力和最大压应力发生在危险截面A 的哪些点上？答：δ+max 发生在d 点。

δ¯max 发生在b 点。

4A 构件中危险点的应力状态如图所示。

构件为钢制：x σ=45MPa ，yσ=135MPa ，z σ=0，xy τ=0，许用应力[]σ=160MPa 。

请用第三强度理论校核该构件的强度。

4B 构件中危险点的应力状态如图所示。

构件材料为铸铁：x σ=20MPa ，y σ=-25MPa ，z σ=40MPa ，xy τ=0，许用应力[]σ=30MPa 。

《工程力学》课程综合复习资料一、计算题1. 已知：受力构件内某点的原始单元体应力如图示。

单位：MPa。

求：指定斜面AB上的应力。

2. 已知：简支梁AB，中点C 处有集中力P，AC段有均匀分布力q，DB段有线性分布力，其最大值为q。

求：A、B两处的约束反力。

（先画出受力图）3. 已知：静不定梁AB，分布载荷q、长度4a，横截面抗弯刚度EIZ 。

求：支座B的反力。

提示：首先选定多于约束，并画出相当系统，列出几何条件。

4. 图示铣刀C的直径D = 9 cm，切削力PZ = 2.2 kN，圆截面刀杆AB长L= 32 cm，许用应力[] = 80 MPa，Me为绕x轴外力偶矩，AB处于平衡状态。

试用第三强度理论，求刀杆AB的直径d。

提示：首先把P Z力向C点平移，明确指出组合变形种类。

5. 一端外伸梁如图所示，已知q,a,3a。

试求梁的约束反力。

提示：必须先画出梁的受力图，明确写出平衡方程。

6. 画出梁的剪力、弯矩图。

（反力已求出）(画图方法不限)。

7. 已知：受力构件内某点的原始单元体应力如图示。

单位：MPa。

求：（1）主应力；（2）主平面方位。

8. 求梁的约束反力。

9. 圆截面压杆，上端为可动铰链约束，下端为固定端约束。

P=100 KN , E=200 GPa , d =4 cm ，L=1.5 m，λP =100 ,λS=60 .欧拉公式为σcr=π2E/λ2经验公式为σcr=a-bλ，a=304MPa，b=1.12MPa 。

稳定安全系数n＝3 。

求：校核压杆的稳定性。

10. 作下图所示梁的剪力图和弯矩图。

11. 下图所示直径为d=20mm的圆截面折杆ABC，已知材料许用应力[]σ=170MPa。

试用第三强度理论确定折杆AB段长度L的许可值。

二、概念问答题1.“ΣMo(F)=0 ”是什么意思？2. 什么是二力构件？其上的力有何特点？3. 材料的基本假设有哪几个？4. 什么是强度失效？5. 脆性材料和塑性料的破坏应力是什么？6. 静力学研究什么问题？7. 理想约束有哪几种？综合复习资料参考答案一、计算题1. 答案：建立参考系oxy,确定原始单元体各面应力其中，o70=α（因为截面方位角为截面外法线与x 轴的夹角）7.3340sin14040cos122040220402sin 2cos 22o o xy yx yx =++-+--=--++=ατασσσσσαMPa 1.224cos14040sin140220402cos 2sin 2o o xy yx =-+-=+-=ατασστα 2. 答案：以整体为研究对象，画受力图，如下图所示。

三
一、选择题（每题4分，共20分）L曲杆煎不计，其上作用一力偶矩为M的力偶，则图(a)中B点的约束反力比图(b)中B 点的反力（
）。

2L I ••I A.大
B.小c.相同D.不能确定
2L ,. .,
8 <4>
<b> 选择题l图2.由同一种材料组成的变截面杆的横截面面积分别为2A和A,受力如图所示，弹性换优E为常数；以下结论（）是正确的。

A.D 截面位移为0
B.O 截面位移为品c.c 截而位移为五气
D.D 截面位移为聂
3.劈裂试验得出的岩石强度表示岩石的(
) • A.抗压强度
B.抗拉强度
C.单轴抗拉强度
D.剪切强度
4.用积分法计算梁的变形时，边界条件是（
）． A. O A =O, 切A =O
8. 011#0; 切11=0
C. Os =O; 心11-#0
0.011=0; 也a =O B C f--l -+--l -叫选择题2图F p _＿一，－A B t 选择题400
5.岩石抗压强度试验中，若加载速率增大，则岩
石的抗压强度(). A.增大C.不峦
1-5题答案： 1. B 2. C 3. B 4. D 5. A
B.减小D.无法判断最新国开电大《工程力学》期末试题3及答案（卷号2661)。

中国石油大学（北京）远程教育学院期末考试 《工程力学》一、题型简答题，8题，每题5分，共40； 计算题，4题，每题15分，共60分）二、题目学号尾数为奇数的同学做题目序号后有“A ”字样的题，学号尾数为偶数的同学做题目序号后有“B ”字样的题（简答题：1A 在铸铁压缩试验中，破坏后的铸铁试样断口平滑呈韧性，与轴线近似成45°。

破坏前，该断口所在斜截面的应力有何特点1B 在铸铁扭转试验中，铸铁断口的形态是什么样的2A 根据铸铁试件扭转破坏断口可以推断，铸铁的扭转破坏和什么因素有很大的关系 2B 电阻应变片（简称电阻片或应变片）应用广泛，它是利用什么原理实现电测的 3A 冲击韧性的物理意义是什么3B 矩形截面梁在截面B 处沿铅垂对称轴和水平对称轴方向上分别作用有P F ，如图所示。

请问最大拉应力和最大压应力发生在危险截面A 的哪些点上'4A 构件中危险点的应力状态如图所示。

构件为钢制：x σ=45MPa ，yσ=135MPa ，z σ=0，xy τ=0，许用应力[]σ=160MPa 。

请用第三强度理论校核该构件的强度。

4B 构件中危险点的应力状态如图所示。

构件材料为铸铁：x σ=20MPa ，y σ=-25MPa ，z σ=40MPa ，xy τ=0，许用应力[]σ=30MPa 。

请用第一强度理论校核该构件的强度。

5A 什么是压杆的临界载荷5B 压杆约束强弱对其稳定性有何影响，请定性说明。

6A 如图所示，一端固定、另一端由弹簧侧向支撑的细长压杆的临界载荷，可采用欧拉公式()22/l EI F Pcr μπ=计算。

请估计该压杆的长度系数μ的取值范围。

`6B 什么是冲击动荷系数7A 构件在突加载荷作用下引起的应力和位移是相应静载荷作用下的几倍7B 将重物突然放到结构上和将重物缓慢放到结构上，哪种情形下结构产生的最大变形大 8A 什么是持久极限8B 影响实际构件疲劳寿命的三个主要因素是什么;计算题：1A 砖夹的宽度为250mm ，杆件AGB 和GCED 在G 点铰接。

中国石油大学（北京）2009—-2010学年第1学期 《 Engineering Mechanics 》期末考试试卷/AClass: Name ： Registration No .： Score ： No. I II III IV V VI VII TotalScoreDate: Jan 22, 2010I. Choose the correct answer for the following questions1. (4 Points) A overhanging beam with its bending moment diagram is shown in the figure. Its allowable tensile and compressive stresses are [σT ] =39.3MPa and [σC ] =58.8MPa respectively. The most reasonable section is .(a) (b) (c) (d)2. (4 Points) If a circular bar in tension fails along its cross section, it is made of _______ material. If a circular bar in tension fails along its section inclined at an angle 45︒, it is made of _______ material.a. Ductileb. Brittlec. Cannot be judged.3. (4 Points) The deflectionexpression of a prismatic beam with length l is)3(6)(2x l EIPx x v -=Then, the supports at two ends are:a. At x = 0 roller and at x =l fixed end;b. At x = 0 fixed end and at x =l pin;c. At x = 0 roller and at x =l pin;d. At x = 0 fixed end and at x =l free.4. (4 points) All the bars with equal section in two trusses are slender and made of same material. Assume the P 1 and P 2 are the critical loads for two trusses respectively. The correct relation following is(a) P 1 > P 2; (b) P 1 < P 2; (c) P 1 = P 2; (d) The relation can’t be determined.5. (4 points) Weight of the body is W, and pushing force is P. W=100N, P=500N. μS =0.3. The static and kinetic sliding friction coefficients between the weight and the wall are μS =0.3, and μk =0.25 respectively. Then the friction between the weight and the wall is (a) 150N; (b) 125N; (c) 100N; (d) 500N.II Answer following questions simply. 1. (3 Points) In pure bending beam test,8 strain gages are pasted up to the beam as shown. Please explain the function of the 8th gage pasted up to the bottom at right angle with axis.2. (4 points) For a real member undergoing repeated loading, the mean stress and amplitude ofthe stress at its critical point are σm and σa respectively as point P shown in following figure of polygonal line for calculating fatigue failure for asymmetric circle. Please write down theaaa2a1σmin , σmax , and character of circle r . For this circle, is it necessary to check member ’s staticstrength?III. (10 points) Determine the force Q required for the equilibrium of the compound lever if P =240N.IV. (12 points) For the beam as shown, draw bending moment and shearforce diagrams.V. (18 points) A circular shaft (d=85 mm ) with tensile load P =280 kN and torque T =10 kN-m isshown in the figure. Let σallow = 160 MPa. (a) Draw the stress element at A and label the stress values on it ；（b ）Exam the shaft with 3th strength theory.A TxP PTA20kN30kN/m30kN/mA B C1mD E 1m1m1mVI. (15 points) Three vertical bars of the same material and same diameter support a rigid horizontal beam at points A, B and C.Determine the axial forces of these three bars.VII. (18 points) A thin curved bar AB has a centerline in the form of quarter circle of radius R, as shown in the figure. The bar is fixed atsupport A and free at B. A horizontal load P acts at free end. Determine the horizontal deflection δh , the vertical deflectionδv .中国石油大学（北京）2009—-2010学年第1学期 《 Engineering Mechanics 》期末考试试卷/BClass: Name ： Registration No .： Score ：No. I II III IV V VI VII TotalScoreI. Choose the correct answer for the following questions1. (4 points) Weight of the body is W, and pushing force is P. W=100N, P=500N. μS =0.3. The static and kinetic sliding friction coefficients between the weight and the wall are μS =0.3, and μk =0.25 respectively. Then the friction between the weight and the wall is (a) 150N; (b) 125N; (c) 100N; (d) 500N.2. (4 Points) The deflection expression of a prismaticbeam with length l is)3(6)(2x l EIPx x v -=Then, the supports at two ends are:a. At x = 0 roller and at x=l fixed end;b. At x = 0 fixed end and at x=l pin;c. At x = 0 roller and at x=l pin;d. At x = 0 fixed end and at x=l free.3. (4 points) All the bars with equal section in two trusses are slender and made of same material. Assume the P1and P2 are the critical loads for two trusses respectively. The correct relation following is(a) P1 > P2; (b) P1 < P2; (c) P1 = P2; (d) The r elation can’t be determined.4. (4 Points) A overhanging beam with its bending moment diagram is shown in the figure. Itsallowable tensile and compressive stresses are [σT] =39.3MPa and [σC] =58.8MPa respectively.The most reasonable section is.(a) (b) (c) (d)5. (4 Points) If a circular bar in tension fails along its cross section, it is made of _______ material. If a circular bar in tension fails along its section inclined at an angle 45︒, it is made of _______ material.a. Ductileb. Brittlec. Cannot be judged.aaa2a1II. (18 points) A circular shaft (d=85 mm ) with tensile load P =280 kN and torque T =10 kN-m isshown in the figure. Let σallow = 160 MPa. (a) Draw the stress element at A and label the stress values on it ；（b ）Exam the shaft with 4th strength theory.A TxP PTIII. (12 points) For the beam as shown, draw bending moment and shear force diagrams.IV . (15 points) Three vertical bars of the same material and same diameter support a rigid horizontal beam at points A, B and C.Determine the axial forces of these three bars.V. (18 points) A thin curved bar AB has a centerline in the form of quarter circle of radius R, as shown in the figure. The bar is fixedat support A and free at B. A horizontal load P acts at free end. Determine the horizontal deflection δh , the vertical deflectionδv . VI. (10 points) Determine the force Q required for the equilibrium of the compound lever if P =240N.VII. Answer following questions simply. 1. (3 Points) In pure bending beam test,A20kN30kN/m30kN/mA B C1mD E 1m1m1m8 strain gages are pasted up to the beam as shown. Please explain the function of the 8th gagepasted up to the bottom at right angle with axis.2.(4 points) For a real member undergoing repeated loading, the mean stress and amplitude ofthe stress at its critical point are σm and σa respectively as point P shown in following figure of polygonal line for calculating fatigue failure for asymmetric circle. Please write down the σmin, σmax, and character of circle r. For this circle, is it necessary to check member’s static strength?中国石油大学（北京）2009—-2010学年第1学期《Engineering Mechanics》期末考试试卷(留学生) Class: Name：Registration No.： Score：No. I II III IV V VI VII TotalScoreI. Choose the correct answer for the following questions1. (5 Points) A overhanging beam with its bending moment diagram is shown in the figure. Itsallowable tensile and compressive stresses are [σT] =39.3MPa and [σC] =58.8MPa respectively.The most reasonable section is .(a) (b) (c) (d)2. (5 Points) For a real member undergoing repeated stress, its character of cycle r=. When r = , its endurance limit is the smallest.a.maxminσσb.minmaxσσc. +1d. –1e. 0f. –∞g. 0.53. (5 Points) Weight of the body is W, and pushing force is P. W=100N, P=500N. μS=0.3. The static and kinetic sliding friction coefficients between the weight and the wall are μS=0.3, and μk=0.25 respectively. Then the friction between the weight and the wall is(a) 150N; (b) 125N;(c) 100N; (d) 500N.4. (5 Points) For two slender compressing bars with same length, same support conditions and made of same material but different cross sectional areas as following, P Cr2=______P Cr1.a. 4b. 8c. 12d. 165. (5 Points) The following figure is a typical low-carbon2aa2a2asteel σ-ε diagram in tension. Points a, b, c, d, e, f and g represent different aspects of mechanical behavior for the material. Please connect the label with its meaning. a yield stress b ultimate stress c elastic limit e percent elongation f proportional limitII. (10 points) Determine the force P required for the equilibrium of the compound lever if Q =4200N. IV . (12 points) For the beam as shown, draw bending moment and shear force diagrams.VI. (20 points) A circular shaft (d=85 mm ) with tensile load P =280 kN and torque T =10 kN-m isshown in the figure. Let σallow = 160 MPa. (a) Draw the stress element at A and label the stress values on it ；（b ）Exam the shaft with 4th strength theory.A TxP PTVI. (15 points) Three vertical bars of the same material and same diameter support a rigid horizontal beam at points A, B and C.Determine the axial forces of these three bars.VII.(18 points) A thin curved bar AB has a centerline in the form of quarter circle of radius R, as shown in theA20kN30kN/m30kN/mA B C1mD E 1m1m1mfigure. The bar is fixed at support A and free at B. A horizontal load P acts at free end.Determine the horizontal deflection δh, the vertical deflection δv.中国石油大学（北京）2009—-2010学年第1学期《Engineering Mechanics》期末考试试卷/C Class: Name：Registration No.： Score：No. I II III IV V TotalScoreI. Choose the correct answer for the following questions1. (5 Points) A overhanging beam with its bending moment diagram is shown in the figure. Itsallowable tensile and compressive stresses are [σT] =39.3MPa and [σC] =58.8MPa respectively.The most reasonable section and beam’s position is .(a) (b) (c) (d)2. (5 Points) For a real member undergoing repeated stress, its character of cycle r=. When r = , its endurance limit is the smallest.a. max minσσ b. minmax σσ c. +1 d. –1 e. 0 f. – ∞ g. 0.53. (5 Points) The block weights 200N and T=100N, F=80N. Neglecting the friction at pulley, the friction between the block and the earth is .4. (5 Points) For two slender compressing bars with same length, same support conditions and made of same material but different cross sectional areas as following, P Cr2=______P Cr1. a. 4 b. 8 c. 12 d. 165. (5 Points) The following figure is a typical low-carbon steel σ-ε diagram in tension. Points a, b, c, d, e, f and g represent different aspects of mechanical behavior for the material. Please connect the label with its meaning.a yield stressb ultimate stressc elastic limit e percent elongation f proportional limitII. (12 points) For the beam as shown, draw bending moment and shear force diagrams.2aa2a2aμS =0.2III ．(18 points) A circular shaft (d=85 mm ) with tensile load P =280 kN and torque T =10 kN-m isshown in the figure. Let σallow = 160 MPa. (a) Draw the stress element at A and label the stress values on it ；（b ）Exam the shaft with 3th strength theory.A TxP PTIV . (15 points) A rigid bar AB of length L is hinged to a wall at A and supported by two verticalbars labeled 1 and 2 attached at points C and D. The bars 1 and 2 have the same cross-sectional area A and are made of the same material (modulus E), but the bar 2 is twice as long as the bar 1. (a) Find the tensile forces N 1 and N 2 in the bars due to the vertical load P acting at end B of the bar. (b) Find the downward displacement B at end B of the bar.V . (15 points) For a closed cylindrical pressure vessel, if r i ≈ r o ≈ r=1000mm, t=10mm, p=0.8MPa. Determine: (a) the hoop and longitudinal stresses in the cylinder and (b) the change in diameter of the cylinder. Let elastic modulus E=200GPa, and Poission ’s ratio ν=0.25.APB CDAh2ha b L1 2V．(15 points) A horizontal bracket ABC is fixed at support A and free at C. The bracket is constructed from a circular cross-sectional bar with constant diameter d. A vertical load P acts at C. Find the vertical displacement δv at C with energy method. E and G are constant.(With other method only 15 60%=9 points are possible).[文档可能无法思考全面，请浏览后下载，另外祝您生活愉快，工作顺利，万事如意!]。