Assistant Design Engineer Interview Questions And Answers

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.

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.

Factors affecting endurance strength are

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

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

The factors involved in arriving at factor of safety are:

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

The factors effecting notch sensitivity are:

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

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

Where,

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)

☛ 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.

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.

Lettering is the presentation of information data on a drawing.

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

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.

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!

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.

Types of variable stresses are:

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

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

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

They are used to solve the problems of variable stresses.

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.

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.

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

Brakes can be classified on the basis of their medium used to brake, they are as follows:
☛ > Hydraulic Brakes: These brakes as their name suggest use a fluid medium to push or repel the brake pads for braking.
☛ > Electric Brakes: These brakes use electrical energy to deplete or create a braking force.
☛ Both the above types of breaks are used primarily for applications where a large amount of energy is to be transformed.
☛ > Mechanical Brakes: They can be further classified on the basis of the direction of their acting force: Radial Brakes: As their names suggests the force that acts on the brakes is of radial direction. They can further be classified into internal and external blades. Axial Brakes: In these types of brakes the braking force is acting in an axial direction as compared to radial brakes.

The thing to remember when you’re answering this question is that there’s no right or wrong answer. The employer is looking for your insight into the industry – and they’re really trying to determine how much you know – and whether you have enough knowledge to try and forecast trends. As I said, with this one, there’s no one ‘correct’ answer – so the best way to really answer this one is to again be honest.

Think about what has happened in the design industry over the last few years ( Ways of design technique has been changed, great designs according to the request of the client can be made in less number of time ) – and think realistically about what might happen in the next few years. Whatever answer you give, make sure you can justify your answer.

The ratio between maximum stresses to working stress is known as factor of safety.

Factor of safety = Maximum stress /Working stress

The different the modes of fractures are:

☛ Mode I (Opening mode) – Displacement is normal to crack surface.
☛ Mode II (Sliding mode) – Displacement is in the plane of the plate.
☛ Mode III (Tearing mode) – Out of plane shear.

An S- N curve has fatigue stress on ‘Y’ axis and number of loading cycles in ‘X’ axis. It is used to find the fatigue stress value corresponding to a given number of cycles.