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!]。
