176. The strain in the cup extrusion for the part shown in figure
     

1. 1. In [D_b /D_p]

   
   
   

   2. In[D_b /(D_b–D_p)]

   
   
   

   3. ln[D_p /(D_b–D_p)]

   
   
   

   4. In[D_b ²/(D_b ²–D_p ²}]

   
   
   

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1. View Hint View Answer Discuss in Forum

   strain = ln			Ai
   			Af

   
   

   strain = ln			D²b
   			D²b - D²p

   
   

   Correct Option: D

   strain = ln			Ai
   			Af

   
   

   strain = ln			D²b
   			D²b - D²p

   
   

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177. In metal forming operation, the true strain in the X-direction is 0.3 and in the Y-direction –0.1. The true strain in the Z-direction is

1. 1. 0

   
   
   

   2. –0.2

   
   
   

   3. 0.2

   
   
   

   4. –0.03

   
   
   

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1. View Hint View Answer Discuss in Forum

   Total volumetric strain = 0
   ε_x + ε_y + ε_z = 0
   0.3 - 0.1 + ε_z = 0
   ε_z = - 0.2

   Correct Option: B

   Total volumetric strain = 0
   ε_x + ε_y + ε_z = 0
   0.3 - 0.1 + ε_z = 0
   ε_z = - 0.2

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178. The function of draw bead in the deep drawing operation is to

1. 1. produce a balance between the amount of stretching and drawing

   
   
   

   2. produce a circular groove on the flange

   
   
   

   3. reduce the drawing load

   
   
   

   4. reduce the wrinkles on the flange

   
   
   

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1. View Hint View Answer Discuss in Forum

   Draw beads decreases circumferential stress or buckling in flange.

   Correct Option: D

   Draw beads decreases circumferential stress or buckling in flange.

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179. In a bending operation, if the modulus of elasticity E is increased keeping all other parameters unehanged, the spring back will

1. 1. increase

   
   
   

   2. decrease

   
   
   

   3. remains unchanged

   
   
   

   4. be independent of E

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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180. A hemispherical cup of radius R is formed in a press working operation. The radius of blank would be

1. 1. √2R

   
   
   

   2. √3R
      

   
   
   

   3. √(2 / 3)R

   
   
   

   4. √(3 / 2)R

   
   
   

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1. View Hint View Answer Discuss in Forum

   Area of Blank = surface area of cup
   

   πR²b	4πR²
   	2

   
   R_b = √2R
   

   Correct Option: A

   Area of Blank = surface area of cup
   

   πR²b	4πR²
   	2

   
   R_b = √2R
   

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