Interview Questions On Strength of Materials

• Can anybody please provide any link to calculate force required to bend a metal sheet into pipe? or describe how is it calculated?

It depends upon the thickness of sheet and required diameter to be formed from the sheet.

• A bearing is designated as 6205 , what is it’s bore diameter:

Generally for bearing bore diameter is 5 times the last number in its designation i.e. for designation 6205, Bore diameter should be 25

• where half nut is use

the half hut is use in lathe .in this half nut mechanism is engaged during the thread cutting operation.and it connect carriage and lead screw.it having 2 portion one half is fixed and one movable.

• why the rail in form of I-beam?

It’s flexural rigidity is high and it’s cross section consume low metal.

• Aluminium foil used for cooking food and storage has one shiny surface and one dull surface. Which surface side be on the outside when the food is wrapped for baking and freezing respectively.
1. Shiny side, shiny side
2. Dull side, dull side
3. Shiny side, dull side
4. Dull side, shiny side

Dull side, Shiny side

Reason:

• The shiny surface of foil loses heat through radiation much faster than the dull surface.
• When the food is baked shiny surface is kept inside, so the heat is kept inside and not to leave.
• When the food is freeze shiny surface kept outside, so the loss of heat is radiated faster which keeps the food in cool.

• what is difference between pressure and stress?

When the force or load acting on the fluid(pneumatic or hydraulic)per unit area is known as PRESSURE.. its purely subjected to fluids……..

when the force or load acting on the object(solid) within the elastic limit of an object create internal resistance to resist the apply load. that internal resistance is known as STRAIN for per unit area of that object.. Its mainlysubjected to solids…

• Is there any rake angle in blade? which is used to shave the beard ?

it consists of negative rake angle.

• stress strain diagram for fluid

PARALLEL LINE HORIZONTAL TO STRSS AXIS

• what’s the range of poisons ratio of a stable material?

Theoretical values are — -1 to 0.5

Practical values are — 0 to 0.5

• Why 220 V A.C. is more dangerous than 220 V D.C
1. The D.C. attracts
2. Peak voltage for A.C. is much larger
3. The body offers less resistance to A.C.
4. Due to some other reasons

Peak voltage for A.C. is much larger

Reason:

D.C. = 220 volt

A.C. = 1.414 x 220 volt

• what is the difference between limit of proportionality and elastic limit

Up to the limit of proportionality stress is directly proportional to strain,follows hooks law,elastic limit is limit for elasticity of material.

Latest Interview Questions in Mechanical | Mechanical Engineering Interview Questions and Answers | Mechanical Engineer Job Interview Questions | Latest Placement Papers | Mechanical Engg Questions

1. What is the importance of the Thermodynamics in the field of Mechanical Engineering?
All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very important for the mechanical engineers.

2. How many Laws of Thermodynamics are there?
There are three laws of the thermodynamics.

First Law: Energy can be neither created nor destroyed. It can only change forms.In any process in an isolated system, the total energy remains the same.

Second Law: When two isolated systems in separate but nearby regions of space, each in thermodynamic equilibrium in itself, but not in equilibrium with each other at first, are at some time allowed to interact, breaking the isolation that separates the two systems, and they exchange matter or energy, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated systems is less than or equal to the entropy of the final exchanging systems. In the process of reaching a new thermodynamic equilibrium, entropy has increased, or at least has not decreased.

Third Law: As temperature approaches absolute zero, the entropy of a system approaches a minimum.

3. State Laws of conservation of energy?
According to the laws of conservation of energy, “energy can neither be created nor be destroyed. It can only be transformed from one form to another.”

4. Is the boiler a closed system?
Yes definitely the boiler is a closed system.

5. What is Carnot engine?
It was being designed by Carnot and let me tell you that Carnot engine is an imaginary engine which follows the Carnot cycle and provides 100% efficiency.

6. Which formula forms a link between the Thermodynamics and Electro chemistry?
Gibbs Helmholtz formula is the formula which forms the link between the thermodynamics and electromagnetism.

∆Hs/R = [∂ lnp /∂ (1/T)]x

where: x – mole fraction of CO2 in the liquid phase
p – CO2 partial pressure (kPa)
T – temperature (K)
R – universal gas constant
α – mole ratio in the liquid phase (mole CO2 per mole of amine)

7. Which is the hardest compound known?
Diamond.

8. What is Hess Law?
According to the Hess law the energy transfer is simply independent of the path being followed. If the reactant and the product of the whole process are the same then same amount of energy will be dissipated or absorbed.

9. Which has more efficiency: Diesel engine or Petrol engines?
Off course Diesel engine has the better efficiency out of two.