Mechanical Engineering

An engineer claims that he had invented a steady flow device that will take air at 4 bar and 20�C and separate it into two streams of equal mass, one at 1 bar and -20�C and the second at 1 bar and 60�C. Furthermore the inventor states that his device operates adiabatically and does not require (or produce) work. Is such a device possible? (Air can be assumed to be an ideal gas with a constant heat capacity of Cp =29.3 J/(mole K).

Engineering, Mechanical Engineering / By

An engineer claims that he had invented a steady flow device that will take air at 4 bar and 20�C and separate it into two streams of equal mass, one at 1 bar and -20�C and the second at 1 bar and 60�C. Furthermore the inventor states that his device operates adiabatically and does not …

An engineer claims that he had invented a steady flow device that will take air at 4 bar and 20�C and separate it into two streams of equal mass, one at 1 bar and -20�C and the second at 1 bar and 60�C. Furthermore the inventor states that his device operates adiabatically and does not require (or produce) work. Is such a device possible? (Air can be assumed to be an ideal gas with a constant heat capacity of Cp =29.3 J/(mole K). Read More »

Describe some of the materials that can be made into P/M parts that could not be used for processes such as casting and forming. Why must powder metals be sintered in controlled atmosphere? What advantages does powder metallurgy offer? The part shown in Figure is to be pressed from fine copper powders using a compaction pressure of 1000 MPa. Dimensions are milimetres. Determine a) the required press tonnage to perform this operation b) the final weight of the part of the porosity is 15%. Assume shrinkage during sintering can be neglected. (the desity of copper =8,97g/cm3) 20

Engineering, Mechanical Engineering / By

EXPERT ANSWER Ans 1:- Powder metallurgy process is used where we need to mix ceramic Or quartz Or any other material with metal. PM is used for the manufacturing of Grinding wheels, welding electrode, magnets, tungsten filament. Basically Tungsten is a material that is processed by PM process as it has very high melting point …

Describe some of the materials that can be made into P/M parts that could not be used for processes such as casting and forming. Why must powder metals be sintered in controlled atmosphere? What advantages does powder metallurgy offer? The part shown in Figure is to be pressed from fine copper powders using a compaction pressure of 1000 MPa. Dimensions are milimetres. Determine a) the required press tonnage to perform this operation b) the final weight of the part of the porosity is 15%. Assume shrinkage during sintering can be neglected. (the desity of copper =8,97g/cm3) 20 Read More »

Q4: A 28 bar linkage mechanism shown in figure 2 is used to transmit rotational motion to a shaft. Evaluate the status and degrees of freedom of the given mechanism. Explain the significance of obtained status and degrees of freedom. Further, the mechanism is considered as a single unbalanced mass acting on a rotating shaft as shown in figure 3. Carry out the balancing of unbalanced mass. Assess the magnitude and inclination of balancing mass with a 15 cm radius of rotation. Specify the type of balancing technique utilized with suitable reasons. (10 Marks) Figure 2 3 May 21, 2020 MIME3220 – Mechanics of machines 1 10 kg M R1= 15 cm 58 – 30 cm- 1.8 m Figure 3

Engineering, Mechanical Engineering / By

EXPERT ANSWER

2) A heavy weight lifter, who is 80kg himself, is holding a weight of 180 Kg as depicted in the picture. The legs of the sportsman are positioned symmetrically. The bones of the leg Femur and Tibia may be considered as hollow shaft with constant diameter. The outer diameter of Femur bone is 4cm and 180 kg inner diameter is 1.5cm. On the other hand, outer diameter of Tibia is 2.5cm and inner is 1.25cm. The elasticity modulus of the bones is E= 18 GPa, and ultimate compression strength is ultimate =200 MPa. a) Draw free body diagram of the legs. b) Find the stresses on each bone (Femur and Tibia) c) The unloaded lengths of each bone are depicted in the figure. Find the lengths of the bones while he is lifting. d) Find maximum amount of the weight that he can hold without a bone crack. Femur 50cm 20″ Tibia 30 cm 25°

Engineering, Mechanical Engineering / By

EXPERT ANSWER

3 Water is supported by a curved gate described by equation y=-xº. The gate is 5 supported with a string passing through the pulley as shown in the figure below. The water is filled up to a height of h=5 m and the string is connected to the gate at H = 7 m. Calculate the tension developed in the string. Assume acceleration due to gravity as 10 m/s² and width of the gate as 20 m. Р 3 H water a) 1200 kN b) 2381 kN c) 3621 kN d) 4361 kN

Engineering, Mechanical Engineering / By

EXPERT ANSWER