Chapter 8, Problem 49RP

Straight rods of 0.30-in. diameter and 200-ft length are sometimes used to clear underground conduits of obstructions or to thread wires through a new conduit. The rods are made of high-strength steel and, for storage and transportation, are wrapped on spools of 5-ft diameter. Assuming that the yield strength is not exceeded, determine (a) the maximum stress in a rod, when the rod, which was initially straight, is wrapped on the spool, (b) the corresponding bending moment in the rod. Use E= 29 * 106 psi.

Two gage marks are placed exactly 250 mm apart on a 12-mm-diameter aluminum rod with E5 73 GPa and an ultimate strength of 140 MPa. Knowing that the distance between the gage marks is 250.28 mm after a load is applied, determine (a) the stress in the rod, (b) the factor of safety.

Two steel plates are to be held together by means of 16-mm-diameter high-strength steel bolts fitting snugly inside cylindrical brass spacers.Knowing that the average normal stress must not exceed 200 MPa in the bolts and 130 MPa in the spacers, determine the outer diameter of the spacers that yields the most economical and safe design.

Knowing that the hole has a diameter of 9 mm, determine (a) the radius rf of the fillets for which the same maximum stress occursat the hole A and at the fillets, (b) the corresponding maximum allowable load P if the allowable stress is 100 MPa.

Determine the largest axial load P that can be safely supported by a flat steel bar consisting of two portions, both 10 mm thick and, respectively, 40 and 60 mm wide, connected by fillets of radius r=8 mm. Assume an allowable normal stress of 165 MPa.

An open-link chain is obtained by bending low-carbon steel rods of 0.5-in. diameter into the shape shown (Fig. ). Knowing that the chain carries a load of 160 lb, determine (a) the largest tensile and compressive stresses in the straight portion of a link, (b) the distance between the cen-troidal and the neutral axis of a cross section

A block of 10-in. length and 1.8 3 1.6-in. cross section is to sup-port a centric compressive load P. The material to be used is a bronze for which E5 14 3 106 psi. Determine the largest load that can be applied, knowing that the normal stress must not exceed 18 ksi and that the decrease in length of the block should be at most 0.12% of its original length

In the structure shown, an 8-mm diameter pin is used at A, and 12- mm diameter pins are used at B and D. Knowing that the ultimate shearing stresses is 100 MPa at all connections and that the ultimate normal stress is 250 MPa in each of the two links joining B and D, determine the allowable load P if an overall factor of safety of 3.0 is desired.

An offset h must be introduced into a metal tube of 0.75-in. outer diameter and 0.08-in. wall thickness. Knowing that the maximum stress after the offset is introduced must not exceed 4 times the stress in the tube when it was straight, determine the largest offset that can be used.