Strength of material viva questions
21. Draw stress-strain curve. explain it.
When the load applied on a metal body then the molecules resist the load and there set up a resisting force. Due to this stress and strain arises. Also, there occurs a microstructural deformation .here we can see the variation of strain with stress. As we can see the curve passes through the 6 points O,A,B,C,D,E, these points have their own meaning about which we are going to discuss.
A: Limit of proportionality -Stress is directly proportional to the strain in the region OA. In this region, material behaves elastically.
B: Elastic limit or yielding– In the region AB, material left proportionality behavior. When the load increases further yielding occurs in the body.
C: Lower yield point– At lower endpoint yielding stop.
D: Ultimate point– After gaining the lower yield point material needs more load to produce strain, and load increases gradually up to ultimate point i.e known as an ultimate point or yield strength of a ductile material.
E: Fracture point– Necking start after the ultimate point i.e the cross-sectional area decreases continuously and got fracture. That point is known as fracture point.
22. What is yield stress?
The stress sY at which yield is initiated is called the yield strength of the material. Yielding means losing the elastic property.
23. What is polar moment of inertia?
The Polar Moment of Inertia is a geometric property of a cross-section. Physically, it is a measure of how difficult it is to turn a cross-section about an axis perpendicular to it (the inherent rotational stiffness of the cross-section). This means that the greater the Polar Moment of Inertia, the more torque is required to turn the shaft by a certain angle.
24. Explain the Radius of gyration.
The radius of gyration is defined as the distance from the axis of rotation to a point where the total mass of the body is supposed to be concentrated, so that the moment of inertia about the axis may remain the same. Simply, gyration is the distribution of the components of an object. It is denoted by K. In terms of the radius of gyration, the moment of inertia of the body of mass M is given as,
Inertia (I) = MK2
25. The relation between Bulk Modulus and Young’s modulus.
26. What is Poisson’s Ratio?
Poisson’s Ratio is the ratio of lateral strain to longitudinal strain.
27. What are the Types of beams?
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