Category: Advance Concept Mechanical Eng

If the temperature of a material is increased, there will be expansion in the material (except ice) and if the temperature is decreased, there will be contraction in the material. If these expansion and contraction occur freely there will be no stress in the material and if these expansion or contraction is prevented then stress…

Any tensile or compressive member which consists of two or more bars in series, usually of different materials, is called composite bars (Figure 12.18). In this case, load on both the rods will be same but strain produced will be different. Figure 12.18 Composite Bar where A1, E1 ∈1 are cross-section area, modulus of elasticity, and strain produced in material…

Figure 12.13 shows stress and strain produced in a compound rod. Figure 12.13 An Assembly of Tube and Bolt where r subscript is used for rod. Rod is subjected to tensile stress and tube is subjected to compressive stress. The reduction in length of tube and extension in rod may be different due to difference in materials…

Any tensile or compressive member which consists of two or more bars or tubes in parallel, usually of different materials, is called a compound bar. Figure 12.12 shows an example of compound bar; it consists of a tube and a rod of different materials. Since the initial length of tube and rod are same, it will remain…

Consider a bar of varying cross-section of uniform strength subjected by a longitudinal stress σ as shown in Figure 12.10. Now consider a small element of axial length δx at a distance of x from smaller end. Let area of cross-section at section x be A and at section x + δx be A + δA. For the element of length δx to be in equilibrium, the total downward force must be equal to the total…

A rod of length l tapers uniformly from a diameter D at one end to diameter d at other end as shown in Figure 12.8. Considering an small element of thickness dx at distance x from the end of diameter d, the diameter of the element is calculated as  Figure 12.8 Extension in Taper Rod Example 12.4: A rod tapers uniformly from 50 to 20 mm diameter in a length…

Hooke’s law states that stress and strain are proportional to each other under elastic limit. Originally, Hooke’s law specified that stress was proportional to strain but later Thomas Young introduced constant of proportionality which is known as Young’s modulus of elastic. Further, this name was superseded by modulus of elasticity. Figure 12.3 demonstrates the Hooke’s Law. Figure…

There are certain behaviours of all materials under the influence of external force. Stress and strain are one of the measures to show these behaviours. Stress is a resistive force per unit area, which is developed internally to oppose the external force subjected to the material. Strain is a measure of deformation of the material…