Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech III MECHANICAL WORKING Previous Question Paper (November/December - 2018 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
Define elastic limit.
Answer
The elastic limit is the maximum stress that a material can withstand without undergoing permanent deformation. Beyond this point, the material will not return to its original shape once the applied load is removed.
Discuss Hook’s law using graphical representation between deformation and applied force.
Answer
Hooke's Law states that within the proportional limit, the stress applied to a material is directly proportional to the strain produced. Graphically, this is represented by a straight line passing through the origin on a force-deformation or stress-strain diagram, where the slope of the line represents the stiffness or modulus of elasticity of the material.
Define plasticity.
Answer
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Differentiate between true stress and engineering stress.
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How do you classify the forming processes?
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Discuss about recovery.
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List out various rolling variables.
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How to estimate torque and horse power in rolling.
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What is extrusion process?
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Discuss how residual stresses after drawing process affects the quality of the product.
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PART - B
Describe the stress at a point with the help of a neat sketch.
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Describe the state of stress in three dimensions with the help of a diagram.
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Briefly describe about the flow curve.
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Explain about Von-Mises’ criterion for yielding of ductile materials.
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Explain the concept of octahedral shear stress and shear strain.
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Describe various forging equipment and their importance.
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What are various forging defects? Describe their causes and remedies.
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List out different types of forging operations and explain any one in detail.
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Explain various factors affecting flow stress in a material during forming process.
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Enumerate various types of rolling mills and their importance.
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List out the different structural shapes formed by Rolling with sketches. Sketch a Cluster Mill and indicate elements in it.
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Discuss about various problems and defects in rolled products with the help of neat sketches.
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How do you analyse an extrusion process through a conical die. Determine total extrusion pressure.
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Derive an equation for power loss in extrusion.
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Explain with sketches the differences between direct and indirect extrusion.
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Discuss various extrusion defects with the help of neat sketches.
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