Assistant Design Engineer Interview Preparation Guide
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Assistant Design Engineer Frequently Asked Questions in various Assistant Design Engineer job interviews by interviewer. The set of questions are here to ensures that you offer a perfect answer posed to you. So get preparation for your new job interview

66 Assistant Design Engineer Questions and Answers:

1 :: Tell us what do you enjoy most about working as a Design Engineer?

Just like the other questions on this page, when answering this question, it’s best to be honest – especially because the answer you give to this one might end up influencing your role, should you get the job! So, you need to think carefully – and not rush into an answer!

With this one, if you can, try and name a few different elements and try to pick things which will make you stand out for all the right reasons. For example, you can design appropriately according the clients requirement, new ideas to make the design more effective and easy to read. You enjoy the design work by implementing new techniques.

2 :: What is Ductility?

It is the property of the material enabling it to be drawn into wire, with the application of tensile force. It must be both strong and plastic. It is usually measured in terms of percentage elongation and reduction in area, (e.g.) Ni, Al, and Cu.

3 :: Tell me what are the factors affecting endurance strength?

Factors affecting endurance strength are

☛ Load ii. Surface finish
☛ Size
☛ Temperature
☛ Impact
☛ Reliability

4 :: What is Griffith theory. (Or) State the condition for crack growth?

A crack can propagate if the energy release rate of crack is greater than crack resistance.

5 :: Tell me the factors involved in arriving at factor of safety?

The factors involved in arriving at factor of safety are:

☛ Material properties
☛ Nature of loads
☛ Presence of localized stresses
☛ Mode of failures

6 :: Tell us what are the factors that affect notch sensitivity?

The factors effecting notch sensitivity are:

☛ Material
☛ Notch radius
☛ Size of component
☛ Type of loading
☛ Grain Structure

7 :: Explain me the bending equation?

The bending moment equation is, M/I = f/y= E/R,


M – Bending moment (M is in N-mm)

I - Moment of inertia about centroidal axis (I is in mm⁴)

f – Bending Stress (f is in N/mm²)

y - Distance from neutral axis (y is in mm)

E - Young’s modulus (E is in N/mm²)

R - Radius of curvature (R is in mm)

8 :: Tell us what safety precautions should be observed while working in the workshop?

☛ 1) Keep shop floor clean, free from oil and other slippery materials.
☛ 2) Wear proper dress and avoid loose clothing and loose hair.
☛ 3) Wear shoes and avoid chapels.
☛ 4) Avoid playing, loose talk and funning inside the shop floor.
☛ 5) Keep good housekeeping and put all unnecessary items and rejected items in scrap box.
☛ 6) Learn everything about the machine before starting and clear all the doubts.
☛ 7) Keep a safe distance from rotating and sliding parts.
☛ 8) Never store inflammable materials inside or around the shop.
☛ 9) Never play with electricity, fire, parts with sharp edge etc.
☛ 10) Keep fire buckets and extinguishers ready for use.

9 :: Explain me what is a Vernier Scale?

This is used to measure very small unit with greater accuracy. It consists of a primary scale and a vernier scale.Vernier scale slides on the primary scale.

10 :: Tell me what is a lettering?

Lettering is the presentation of information data on a drawing.

11 :: Tell me what are Cutting Plane Lines?

These are thick lines used to indicate the location of cutting planes in sectioning and the viewing position of removed pieces.

12 :: Please explain on what basis can sliding contact bearings be classified?

Sliding contact bearings can be classified on the basis of the thickness of the lubricating agent layer between the bearing and the journal. They can be classified as follows:
☛ > Thick film bearings: These type of bearings have their working surface separated by a layer of the lubricant. They are also known as hydrodynamic lubricated bearings.
☛ > Thin film bearings: In this type of bearings the surfaces are partially in direct contact with each other even after the presence of a lubricant. The other name for such type of bearings is boundary lubricated bearings.
☛ > Zero Film Bearings: These type of bearings as their name suggests have no lubricant present between the contact layers.
☛ > Externally or hydrostatically pressurized lubricated bearings: These bearings are able to without any relative motion support steady loads.

13 :: Tell me what attracted you to be a design engineer?

With this question, the employer/interviewer is really interested in your motivation – and they’re also trying to find out why you applied for the job in question (particularly if this is your first job as a design engineer). With this answer, they’re looking for you to be passionate and enthusiastic and for you to at least interest in the profile.

With this one, it’s best to be honest. Why did you want to get into design? Was it because it seemed a bit different? It was good fit for your skills? It seemed like an interesting challenge? Or did you just fall into it? If it was the latter, it’s ok to say that- but be sure why you want to work in this area. Remember- they’re looking for honesty- and to gain some insight into you as an individual and how you might fit into their team- so try and sound at least little bit credible!

14 :: What is fatigue?

When a material is subjected to repeated stress, it fails at stresses below the yield point stress; such type of failure of the material is called fatigue.

15 :: Tell us what are the types of variable stresses?

Types of variable stresses are:

☛ Completely reversed or cyclic stresses
☛ Fluctuating stresses
☛ Repeated stresses

16 :: Tell us what are the factors to be considered in the selection of materials for a machine element?

While selecting a material for a machine element, the following factors are to be considered

☛ Required material properties
☛ Manufacturing ease
☛ Material availability
☛ Cost

17 :: Tell me what is the use of Goodman & Soderberg diagrams?

They are used to solve the problems of variable stresses.

18 :: Explain me what are the factors that can affect the Factor of safety selection?

The factor of safety is used in designing a machine component. Prior to selecting the correct factor of safety certain points must be taken into consideration such as:
☛ > The properties of the material used for the machine and the changes in its intrinsic properties over the time period of service.
☛ > The accuracy and authenticity of test results to the actual machine parts.
☛ > The applied load reliability.
☛ > The limit of stresses (localized).
☛ > The loss of property and life in case of failures.
☛ > The limit of initial stresses at the time period of manufacture.
☛ > The extent to which the assumptions can be simplified.

The factor of safety also depends on numerous other considerations such as the material, the method of manufacturing , the various types of stress, the part shapes etc.

19 :: Explain me what are the different theories of failure under static load?

The main theories of failure of a member subjected to bi-axial stress are as follows:
☛ > Maximum principal stress theory ( Rankine’s theory): This theory states that failure occurs at a point in member where the maximum principal or normal stress in a bi-axial system reaches the maximum strength in a simple tension test.
☛ > Maximum shear stress theory ( Guest’s or Tresca’s theory): This theory states that failure occurs when the biaxial stress reaches a value equal to the shear stress at yield point in a simple tension test.
☛ > Maximum principal strain theory ( Saint Venant theory): This theory states that failure occurs when bi-axial stress reaches the limiting value of strain.
☛ > Maximum strain energy theory ( Haigh’s theory): This theory states that failure occurs when strain energy per unit volume of the stress system reaches the limiting strain energy point.
☛ > Maximum distortion energy theory ( Hencky and Von Mises theory): This theory states that failure occurs when strain energy per unit volume reaches the limiting distortion energy.

20 :: Explain me what are the functions of a scale?

☛ (a) To measure distance accurately.
☛ (b) For making drawing to scale either in full size, reduced size or enlarged size.