Getting a job right after stepping out of college is a dream for many. Apart from a degree with good grades, one needs to fare well at the interview which is crucial to selection. How do you do that? Smart is the way to go about it. Mechanical Engineering interview questions, according to a survey, are majorly technical.
So, if you have a good grip on the technical portion, you are good to go.
Here is a list of interview questions for mechanical engineering to go through right before you step into the interview room.
1. What is a nozzle and what happens in a nozzle?
A device that is used to control the fluid’s direction is called a nozzle. It also changes some of the properties of the fluid flowing through it. It is used to increase the speed of the fluid stream. It is required where the velocity is high and the pressure is low.
2. What rules should be considered while designing castings?
The design casting should be kept as simple as possible. The concentration of stresses sharp corners must be avoided and to do so, frequent use of fillets need to be avoided. There should be uniform section thickness. The variations however need to be done gradually. No abrupt changes should be done to the thickness. Flat surfaces need to be avoided s it is not easy to create true/actual large spaces. There should be a minimum level of ribs and web used for stiffening. Also, the use of curved shapes is plausible for improving the stress handling of the cast.
3. Briefly describe the different processes of cold drawing.
Wire drawing- The first step in rod and bar drawing is to pickle, wash and coat hot drawn bars. This is done to prevent oxidation. After this, to decrease diameter to attain the desired diameter (by a reduction in the size), several dies are used for the process. The material used for the reduction process is carbide material.
Rod and Bar drawing- The first step in rod and bar drawing is to pickle, wash and coat hot drawn bars. This is done to prevent oxidation. After this, for the process of cold drawing, a draw bench is used. The Swaging operation is used to reduce the diameter of the rod so that an end is made possible to enter the drawing die. To draw the bench, the end is fastened by a chain. Jaws of the carriage are used to grip the end. This method leads to the attainment of dimensional accuracy and high surface finish. There is no use of further machining after this process and the products can be used directly.
Tube drawing-This drawing is more or less similar to the bar drawing process. In tube drawing, a draw bench is used.
Explain the various theories of failure that are there under a static load.
4. With respect to bi-axial stress, there are various theories for the failure.
1. Guest’s theory or Tresca’s theory- According to the maximum stress shear theory, the failure is due to the shear stress reaching the level of bi-axial stress in simple tension at the yield point.
2. Rankine’s theory- According to the maximum principal stress theory, the failure is due to the maximum normal or principal stress reaching the maximum strength in a bi-axial system in a simple tension test.
3. Haigh’s theory- According to the maximum strain energy theory, the failure is the strain energy per unit volume of stress reaching the limiting strain energy point.
4. Saint Venant theory- According to the maximum principal strain theory, the failure is due to the bi-axial stress reaching the limiting value of strain.
5. Hencky and Von Mises theory- As per the maximum distortion energy theory. The failure is due to the strain energy per unit reaching the limiting distortion energy.
5. What things should be kept in mind while forging design?
Designing is the first step in the creation of a product. Therefore, it must be given ample amount of time so that there is no room for any discrepancy in it. Grains and fibers should be achieved in a radial flow in the forged components. Press and drop forgings (forged items) need to have a parting line. It is done for dividing the forging into two equal parts. The ribs in forging must be done carefully so that it is not thin or high. The parting line in forging should remain far in a single plane. To make forging easier, the surfaces of the metal, must have sufficient drafts.
Being well versed with the basics is always yields the best results. Having confidence in oneself is of utmost importance. Preparing a mechanical engineering , is just one step in the right direction of your career. It is a stepping stone for that dream job that you want to have.
