A cylindrical part is warm upset compressed by forging in an open die. Before forging, the diameter axially is 20mm and the height is 60mm. The coefficient of friction at the die-work interface is 0.20. The flow curve of the work material at forging temperature is defined by a strength coefficient of K is 530MPa, and a strain-hardening exponent of n is 0.23. Assume the volume of the part remained unchanged during the whole process and no barreling effects.

a. The maximum strain of the part is 0.485. What is the maximum area of contact between the die and the part?
b. What is the maximum force required to forge this part to its maximum area?

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Water at 55c flows across a flat plate whose surface temperature is held constant at 95c. if the temperature gradient at the plate's surface for a given value of x is 18 c/mm, find a) local heat transfer coefficient. b) heat flux