材料力學(xué)試卷：201305 MOM mid-term exam

1、姓名 學(xué)號 學(xué)院 專業(yè) 座位號 ( 密 封 線 內(nèi) 不 答 題 )密封線線_ _ 誠信應(yīng)考,考試作弊將帶來嚴(yán)重后果！ 華南理工大學(xué)期中考試Mechanics of Materials注意事項：1. 考前請將密封線內(nèi)填寫清楚； 2. 所有答案請直接答在試卷上(或答題紙上)； 3考試形式：閉卷； 4. 本試卷共六大題，滿分100分，考試時間120分鐘。ProblemIIIIIIIVVVITotal scorescoreGrading personI. Simple calculation problems（5 problems, score 5 each, total score 25）01. A

2、 hollow circular post ABC (see figure) supports a load P1 = 7.5 kN acting at the top. A second load P2 is uniformly distributed around the cap plate at B. The diameters and thicknesses of the upper and lower parts of the post are dAB = 32 mm, tAB = 12 mm, dBC = 57 mm, and tBC = 9 mm, respectively.If

3、 it is desired that the lower part of the post have the same compressive stress as the upper part, what should be the magnitude of the load P2?02. Determine the section modulus of the cross-sectional area for bending SZ for the section shown in the figure if the diameter of the circle is d, and side

4、 length of the hollow square is b, and .03. Three different materials, designated A, B, and C, are tested in tension using test specimens having diameters of 12 mm and gage lengths of 50 mm (see figure). At failure, the distances between the gage marks are found to be 54.5 mm, 63.2 mm, and 69.4 mm,

5、respectively. Also, at the failure cross sections the diameters are found to be 11.46, 9.48 and 6.06 mm, respectively.Determine the percent elongation and percent reduction in area of each specimen, and then, using your own judgment, classify each material as brittle or ductile.04. An element in tri

6、axial stress (see figure) is subjected to stressesassume modulus of elasticityand Poissons ratio. Determine the following quantities: (a) the principle stresses and, (b) the maximum normal strain. Show the principle stresses on a sketch of a properly oriented element. 05. Determine the angle of rota

7、tion in the Fig.(a) based on the appendix, as shown in Fig.(b) . Appendix: Fig. (a) Fig.(b)II. Draw shear-force Fs and bending-moment M diagrams for the beam (see figure).（score 15） III.A metal beam with span L=1m is simply supported at points A and B. The uniform load on the beam is q=28kN/m. The c

8、ross section of the beam is rectangular with width b=25mm and height h=10mm. Determine the maximum normal stress and maximum shear stress in the beam. （score 15）IV. Forces P1 = 6.7 kN and P2 = 11 kN are applied at joint C of plane truss ABC shown in the figure part (a).Member AC has thickness tAC =

9、8 mm and member AB is composed of two bars each having thickness tAB/2 = 5mm see figure part (b). Ignore the effect of the two plates which make up the pin support at A.If the allowable shear stress in the pin is 90 MPa and the allowable bearing stress in the pin is 150 MPa,What is the minimum requi

10、red diameter dmin of the pin? （score 15）V. A shear wall in a reinforced concrete building is subjected to a vertical uniform load of intensity q and a hori-zontal force H, as shown in the first part of the figure. (The force H represents the effects of wind and earthquakeloads.) As a consequence of

11、these loads, the stresses at point A on the surface of the wall have the values shownin the second part of the figure (compressive stress equal to 10 MPa and shear stress equal to 2 MPa).(a) Determine the principal stresses and show them on a sketch of a properly oriented element.(b) Determine the m

12、aximum shear stresses and associated normal stresses and show them on a sketch of a properly oriented element. （score 15）VI. A stepped shaft ABCD consisting of solid circular segments is subjected to three torques, as shown in the figure. The torques have magnitudes 3000Nm, 2000 Nm , and 800Nm. The length of each segments is 0.5m, and the diameters of the segments ar