The fatigue data for a ductile cast iron are given as follows: stress amplitude [mpa (ksi)] cycles to failure 248 (36.0) 1 × 105 236 (34.2) 3 × 105 224 (32.5) 1 × 106 213 (30.9) 3 × 106 201 (29.1) 1 × 107 193 (28.0) 3 × 107 193 (28.0) 1 × 108 193 (28.0) 3 × 108

(a) make an s–n plot (stress amplitude versus logarithm cycles to failure) using these data.

(b) what is the fatigue limit for this alloy?

(c) determine fatigue lifetimes at stress amplitudes of 230 mpa (33,500 psi) and 175 mpa (25,000 psi).

(d) estimate fatigue strengths at 2 × 105 and 6 × 106 cycles.

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

Apump is used to circulate hot water in a home heating system. water enters the well-insulated pump operating at steady state at a rate of 0.42 gal/min. the inlet pressure and temperature are 14.7 lbf/in.2, and 180°f, respectively; at the exit the pressure is 60 lbf/in.2 the pump requires 1/15 hp of power input. water can be modeled as an incompressible substance with constant density of 60.58 lb/ft3 and constant specific heat of 1 btu/lb or. neglecting kinetic and potential energy effects, determine the temperature change, in °r, as the water flows through the pump.

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.