Design a C.I. flange coupling for a mild steel shaft transmitting 90 kW at 250 rpm. The allowable shear stress for shaft material is 40 MPa. The allowable shear stress and crushing stress for key and bolt material are 45 MPa and 85 MPa respectively. The permissible shear stress for C.I. is 14 MPa. The key is having square cross-section with (width)=(thickness)=[(diameter of shaft)|4]. The number of bolts is 6. The bolts are fitted in reamed and ground holesand are fingure tight.
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