Mechanical Engineering Principles

12 MECHANICAL ENGINEERING PRINCIPLES 1.10 Modulus of rigidity Experiments have shown that under pure torsion (see Chapter 10), u ...

THE EFFECTS OF FORCES ON MATERIALS 13 Therefore, drop in thermal strain = − 30 × 106 Pa 2 × 1011 Pa =− 1. 5 × 10 −^4 =αT from wh ...

14 MECHANICAL ENGINEERING PRINCIPLES these two positions (i.e. at the position A-A in Figure 1.13). To achieve this, it will be ...

THE EFFECTS OF FORCES ON MATERIALS 15 Rearranging gives: σ 2 = PE 2 (A 1 E 1 +A 2 E 2 ) ( 1. 8 ) and σ 1 = PE 1 (A 1 E 1 +A 2 E ...

16 MECHANICAL ENGINEERING PRINCIPLES Now try the following exercise Exercise 5 Further problems on compound bars Two layers of ...

THE EFFECTS OF FORCES ON MATERIALS 17 exceeded, the force that will stretch the wire 5 mm is: (a) 150 N (b) 250 N (c) 90 N (d) 4 ...

2 Tensile testing At the end of this chapter you should be able to: describe a tensile test recognise from a tensile test the l ...

TENSILE TESTING 19 The yield stress gives an indication of the ductility of the material (see Chapter 1). (v) For mild steel, th ...

20 MECHANICAL ENGINEERING PRINCIPLES Load (kN) 0 8 19 29 36 Extension (mm) 0 0.015 0.038 0.060 0.072 The maximum load carried by ...

TENSILE TESTING 21 (b) Ultimate tensile strength = maximum load original cross-sectional area = 120000 0. 0001767 = 679 × 106 Pa ...

22 MECHANICAL ENGINEERING PRINCIPLES A 10 20 30 40 C B Extension /mm Load /kN 0 1.0 2.0 3.0 4.0 5.0 P Figure 2.5 (b) Gradient of ...

TENSILE TESTING 23 (b) Yield stress = load when yield begins to take place original cross-sectional area = 80000 N 250 × 10 −^6 ...

24 MECHANICAL ENGINEERING PRINCIPLES (a) the limit of proportionality (b) the elastic limit (c) the yield point (d) the percenta ...

3 Forces acting at a point At the end of this chapter you should be able to: distinguish between scalar and vector qu- antities ...

26 MECHANICAL ENGINEERING PRINCIPLES original position. Thus a ball bearing in a hemispherical cup is in stable equilibrium, as ...

FORCES ACTING AT A POINT 27 3.4 The resultant of two coplanar forces For two forces acting at a point, there are three possibili ...

28 MECHANICAL ENGINEERING PRINCIPLES 3.5 Triangle of forces method A simple procedure for the triangle of forces method of vecto ...

FORCES ACTING AT A POINT 29 13 N at 0°and 25 N at 30° [36.8 N at 20°] 5 N at 60°and 8 N at 90° [12.6 N at 79°] 1.3 kN at 45°and ...

30 MECHANICAL ENGINEERING PRINCIPLES Problem 5. Use the cosine and sine rules to determine the magnitude and direction of the re ...

FORCES ACTING AT A POINT 31 (iii) From the nose ofab,drawbcto represent forceF 3 (iv) The resultant vector is given by lengthoci ...