1. What are the assumptions made in the analysis of curved bars?
1.Plane sections remain plane during bending.
2.The material obeys Hooke's law.
3.Radial strain is negligible.
4.The fibres are free to expand or contract without any constraining effect from the adjacent fibres.
2. Write the formula for stress using Winkler-Bach theory?
3. Define unsymmetrical bending.
If the plane of loading or that of bending, does not lie in (or parallel to) a plane that contains the principal centroidal axisof the cross-section, the bending is called unsymmetrical bending.
4. What are the reasons for unsymmetrical bending?
1.The section is symmetrical but the load line is inclined to both the principal axes. 2.The section itself is unsymmetrical and the load line is along the centroidal axis.
5. How will you calculate the stress due to unsymmetrical bending?
6. How will you calculate the distance of neutral axis from centroidal axis.
-ve sign shows that neutral axis is below the centroidal axis.
7. How will you calculate the angle of inclination of neutral axis with respect to principal axis?
8. Write the formula for
deflection of a beam causing unsymmetrical bending.
Where K = a constant depending upon the end conditions of the beam and the position of the load along the beam
l = length of the beam
q= angle of inclination of load W with respect to VV principal axis
9.How will you calculate the resultant stress in a curved bar subjected to direct stress and bending stress.
?r = ?o + ?b
where so = Direct stress = P/A sb = Bending stress
10. How eill you calculate the resultant stress in a chain link.
?r = ?o + ?b
where ?o = Direct stress = P/2A x sin q
?b = Bending stress
11. What is shear centre or angle of twist?
The shear centre for any transverse section of the beam is the point of intersection of the bending axis and the plane of the transverse section.
12. Who postulated the theory of curved beam?
Winkler-Bach postulated the theory of curved beam.
13. What is the shape of distribution of bending stress in a curved beam? The distribution of bending stress is hyperbolic in a curved beam.
14. Where does the neutral axis lie in a curved beam?
The neutral axis does not coincide with the geometric axis.
15. What is the nature of stress in the inside section of a crane hook? Tensile stress
16. Where does the maximum stress in a ring under tension occur?
The maximum stress in a ring under tension occurs along the line of action of load.
17. What is the most suitable section for a crane?
18. What is pure bending of a beam?
When the loads pass through the bending axis of a beam, then there shall be pure bending of the beam.
19. How will you determine the product of inertia.
The product of inertia is determined with respect to a set of axes which are perpendicular to each other.
The product of inertia is obtained by multiplying each elementary area dA by its co-ordinates x and y and integrated over the area A.
IXY = òxy dA
20. Define principal moment of inertia.
The perpendicular axis about which the product of inertia is zero are called
'principal axes' and the moments of inertia with respect to these axes are called as principal moments of inertia.
The maximum moment of inertia is known as Major principal moment of inertia and the minimum moment of inertia is known as Minor principal moment of inertia.