help please A heavyduty pump assembly is bolted to the base

help please

A heavy-duty pump assembly is bolted to the base frame with a total apparent contact area of 425 cm^2 (identified in red in the drawing). The mounting brackets and the base frame are made of Type 20 grey cast iron. Estimate the average force that should be generated by tightening the bolts to allow 20% of apparent contact surface to actually develop contact.

Solution

Crushing strength, S = 570 MPa

Area, a= 425 cm² = 0.0425 m²

Apparent contact area a1= 0.2 * a= 0.0085 m²

Force generated = S*a1 = 4.845 MN