# How to Prepare Machine Design for GATE Mechanical Engineering?

I am writing this blog on **Machine Design (M.D.)** for the **GATE** Mechanical/Production & Industrial aspirants. Machine Design (M.D.) is a very important subject from the exam point of view. This blog will be very useful for those aspirants who are doing self-study. Follow this blog to prepare effectively for this subject.

**Note: In this blog, the time duration and day wise analysis are given, so, the time taken by any aspirants may vary that depends on the aspirant’s intellectual. Attempting Topic wise and subject wise test series regularly is highly recommendable.**

**Marks analysis of previous year GATE questions: Machine Design**

**Design for Static Loading: 13 marks**

Marks |
No. of questions |

1 mark | 4 |

2 marks | 2 |

5 marks | 1 |

**Design for dynamic Loading, Theories of failure, fatigue strength and the S-N diagram: 27 marks**

Marks |
No. of questions |

1 mark | 8 |

2 marks | 7 |

5 marks | 1 |

**Principles of the design of machine elements such as bolted, riveted and welded joints: 65 marks**

Marks |
No. of questions |

1 mark | 9 |

2 marks | 18 |

5 marks | 4 |

**Shaft, Gears & Keys: 55 marks**

Marks |
No. of questions |

1 mark | 3 |

2 marks | 16 |

5 marks | 4 |

**Bearings Design: 44 marks**

Marks |
No. of questions |

1 mark | 13 |

2 marks | 8 |

5 marks | 3 |

**Brakes and clutches: 37 marks**

Marks |
No. of questions |

1 mark | 3 |

2 marks | 12 |

5 marks | 2 |

**Springs & power screws: 22 marks**

Marks |
No. of questions |

1 mark | 4 |

2 marks | 4 |

5 marks | 2 |

# Important Topics, Preparation Strategy & Tips & Instructions to Prepare Machine Design

Let’s start with some of the important topics in Machine Design.

**Design for static Loading:**

**Day-1**

**Topics: **Modes of failure, Factor of safety (FOS), Stress-strain relationship, Shear stress and Shear strain, Stresses Due to Bending Moment and Stresses Due to Torsional Moment, Eccentric Axial loading, residual stresses**.**

**Tips and instructions**: Although very few questions have been asked in GATE till now but it is a very important topic as it forms the basics for all the further topics in MD. Solve numericals from the standard books and attempt test series as much as possible**.**

**Books for solving numerical and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **5-6 hours

**Design for dynamic Loading, Theories of failure, fatigue strength and the S-N diagram:**

**Day-2 & 3**

**Design for Dynamic Loading or Design Against Fluctuating Load, Endurance or Fatigue strength, S-N curve:**

**Topics:** Stress concentration, Stress Concentration Factors, Fluctuating stresses like (Alternating stress, completely reversed loading, Repeated stresses), Fatigue Failure, Endurance Limit, Notch Sensitivity, Endurance Limit approximations (Relationship between endurance limit and ultimate strength), S-N curve Reversed Stresses-Design for Finite & Infinite Life, Cumulative Damage in Fatigue, Gerber, Soderberg and Goodman lines, Modified Goodman diagrams.

**Tips and instructions**: In this section mostly, questions will be from Graphs. So, one must have the problem-solving skills using graphs. Practice questions from the standard books and make notes of tough and conceptual questions. This part of machine design is very important and you can expect questions from it almost every year, so learn from the standard books and make notes simultaneously. Give test series as much as possible. Numericals based on S-N graph, Soderberg, Goodman and Gerber lines, Fluctuating loads are very important.

**Books for solving numerical and clearing concepts:** Design of machine elements by “V.B. Bhandari”.

**No. of hours: **10-12 hours

**Principles of the design of machine elements such as bolted, riveted and welded joints:**

**Day- 4, 5 & 6**

**Riveted joint:**

**Topics**: Definition, Types of Riveted joints, types of Failure, strength equations, the efficiency of joints, Fullering and Caulking (For theoretical questions)**.**

**Tips and instructions**: Learn all the types of riveted joints very well, that will be very helpful in solving numerical. Numericals on failure, efficiency and strength equations are very important. Attempt test series.

**Welded joints:**

**Topics**: Definition, stress relieving of welded joints, Description of Butt joints, Description of Fillet joints, Strength of Butt welds, Strength of parallel Fillet welds, Strength of transverse Fillet weld, Maximum shear stress in parallel Fillet weld, Maximum shear stress in Transverse Fillet weld, Axially Loaded unsymmetrical welded joints, Eccentric loading in the plane of weld, welded joint subjected to Bending Moment & Torsional moment, Welding symbols.

**Tips and instructions**: Practice Numericals of all types of welded joints as much as possible from the standard book and solve previous year GATE questions, Memorize all the welding symbols. Learn stress relieving of welded joints for Theoretical questions. Attempt test series

**Bolted joints:**

**Topics**: Definition, eccentrically loaded bolted joints in Shear, eccentric Load Perpendicular to the axis of Bolt, the Eccentric load on a circular base.

**Tips and instructions**: For practicing numericals previous year questions are the best questions for practicing, also practice questions from standard books. You must practice lots of question for the Bolted joints as it is very much important from the GATE point of view. Attempt test series.

**Books for solving numericals and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **17-18 hours

When done with each subject you can refer to Revision Plan for GATE ME so that you can fully get prepared for GATE Exam

**Shaft, Gears & Keys:**

**Day- 7 & 8**

**Gears**

**Topics: **Classification of Gears, Law of Gearing, Terminology of Gears and its Formulae, Standard systems of Gear Tooth (just memorize the diagrams of the full depth and stub), Interference and undercutting, Backlash, Force Analysis, Gear Tooth Failure, Beam strength of Gear Tooth, Wear strength of Gear Tooth.

**Tips and instructions**: Some topics from gear are common in TOM and MD. So, I have mentioned only those topics which are in MD. Few theoretical questions also have been asked from this section, so learn the theories of “Interference, undercutting, Gear Tooth Failure, Elimination of interference” very well. Theories can be asked from these topics. Practice numericals from the standard books and Previous GATE questions. Numericals from Force analysis, Beam strength, Wear strength are very important, so solve examples from the book and if you have time then you can solve exercise unsolved problems. Attempt tests as much as possible.

**Shaft and Keys:**

**Keys:**

**Topics**: Saddle key, sunk key, woodruff key, Feather keys**. **(Read basics)

**Tips and instruction: **This is not so important topic from the GATE point of view. So, solve previous year questions directly will be better as these questions can be solved by using common sense. If you have a problem with these topics then you may refer “V.B. Bhandari” book for reference.

**Books for solving numericals and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **9-10 hours

**Bearings Design:**

**Day-9 & 10**

**Rolling contact bearing:**

**Topics:** Classification of Bearings, Types of Rolling contact bearings, Stribeck’s Equation (Diagram and formula only), Equivalent Bearing load, Dynamic load carrying capacity, Load-Life Relationship, Design for cyclic loads and speeds.

**Tips and instructions: **Numericals based on Load-Life Relationship, Dynamic load are very important, Theories based on classification and types of the bearing are very important as a 1-mark question can be framed. You must know the type of bearing that is being used for the type of application.

**Sliding contact bearing:**

**Topics:** Lubrication and its basic modes like Thick film and Thin film lubrication, Thick film – Hydrostatic and Hydrodynamic lubrication, Viscosity Index (VI), Petroff’s Equation, McKee’s Investigation, and *µN/p *curve, bearing characteristics number, Somerfield number, Comparison of sliding contact bearing and Rolling contact bearing.

**Tips and instructions: ** Numericals based on Somerfield no. and Heat generated (power required) numerals are very important, Theories on Thick and Thin film lubrication, Bearing Characteristics no. and *µN/p *curve are important from the GATE point of view**.**

**Books for solving numerical and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **8-10 hours

**Brakes and clutches:**

**Day-11 & 12**

**Brakes:**

**Topics: **Definition of Brakes, Energy Equations, Block Brake with Short Shoe, Band brakes.

**Tips and instruction: **Numericals based on block brake and band brake are very important. Many good questions have been asked till now in the GATE exam, you can practice all of them. Also, solve numerical problems from the standard books. This topic is very important, so do lots of practice and attempt test series as much as possible.

**Clutches:**

**Topics:** Definition of clutches, Classification of clutches, Torque transmitting capacity for uniform Pressure Theory and uniform wear theory, Torque transmitting capacity of the clutch is maximum when d/D=0.577 for uniform wear theory, Multi-disk clutches, cone clutches, centrifugal clutches.

**Tips and instruction: **Derivation of Torque Transmitting capacity for both the theories must be covered and final formula for Torque and Axial force must be memorized. Solve previous year GATE questions. Practice numerical questions from standard books as much as possible as it is a very important topic. Fewer topics are there and important from the GATE point of view, formulae and Diagrams with notations for Multi-disk, cone and centrifugal clutches should be memorized. Attempt test series.

**Books for solving numerical and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **10-12 hours.

**Springs & power screws: **

**Day-13**

**Springs: **

**Topics: **Types of springs, the terminology of Helical springs, Stress and deflection equations, Wahl factor, Series and parallel connections, Spring materials.

**Tips and instruction: **Derivation of Stress & deflection of springs should be practiced and also practice relevant numerical problems. Few theoretical questions have been asked from spring materials. Attempt test series for more questions.

**Power screws:**

**Topics:** Definition of Power screws, Forms of threads, Terminology of power screw, Torque Requirement-Lifting and Lowering Load, Self-locking Screw, Efficiency of different screws.

**Tips and instruction: **This portion is not important but few unpredictable questions asked in GATE exam every year so you should prepare for the worst situation so one should not leave this portion and prepare well this Unit. Attempt test series for more questions.

**Books for solving numerical and clearing concepts: **Design of machine elements by “V.B. Bhandari”.

**No. of hours: **8-9 hours

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So this was the preparation strategy that can help you to thoroughly prepare for Machine Design for GATE (ME) Exam. Similarly, I have also told the *preparation strategy for Engineering Mechanics*.

Hope this blog proves to be helpful for you in setting strategy for Machine Design. And if you have any doubt or question for the same you can let me know in the comment section below.