FEA interview questions in Engineering mechanics

1.Define: Moment of a force

• Moment of force is the Product of magnitude of force and distance between line of action of force, point about which the force causing rotation.

2.What is moment of inertia?

• Moment again multiplied by distance between line of action of force point about which the force causing rotation.     
• The moment of inertia which forms the basis of dynamics of rigid bodies and strength of materials.

3.What is area moment of inertia? What is it significance and its conjunction?

• Moment of inertia for plane figures is called area moment of inertia.
• When examined by itself there is no physical important for moment of inertia. It’s a just mathematical expression usually denoted by I.
• Structural meaning of Moment of inertia Measure ability of the beam to resist bending.
• Area moment inertia is conjunction with deflection or deformation.

4.What is mass moment of inertia? And it’s the structural meaning?

• Moment of inertia for Solid or 3D figures is called mass moment of inertia.it is conjunction with rotation of rigid bodies.
• Structural meaning of mass moment of inertia Measure of resistance of a body to rotation.

5.What is Polar moment of inertia? And it’s the structural meaning?

• Polar moment of inertia is equal to the sum of area moments of inertia about any two mutually perpendicular axes in its plane and intersecting on the polar axis.
• Structural meaning of Polar Moment of inertia Measure ability of the Shaft to resist torsion

6.What is Radius of gyration or radius of rotation?

Distance from that axes at which all the elemental parts of the lamina would have to be placed

                   

  r =√ I/A

       Where,

                   r – Radius of gyration

                   I – Moment of inertia

                   A – Area

7.What is centroid?

• The point where the whole area of the figure is assumed to be concentrated.
• It is also called as Centre of area.
• Which is same as Centre of gravity when the bodies have area only and not weight.
• The weightless lamina’s, plane figures have Centroid.

8.What is centre of gravity?

• The point through the whole weight of the body assumed to act.
• The position of the c.g depends upon the shape of the body. C.g may be within the boundary of the body or outside of the boundary of the body.

9.How to determine centre of gravity of object?

  There are two methods to find the centre of gravity.

1. Balancing method
2. Suspension method