Question

A short segment of a conveyor belt transportation system in a manufacturing plant needs to be suspended from the ceiling. The segment will be 2 m long and has a mass of 50 kg. 400 kg parts roll across the segment such that the leading edge of one part begins to enter the conveyor belt at the moment the trailing edge of the previous one leaves. The conveyor belt will be supported from the ceiling using four cylindrical rods hanging in pairs as shown below:

PART 0.5 m l m 0.5 m

What diameter should the support rods be for a factor of safety of 1.25 with respect to failure at N = 10⁶ cycles? The rods will be made of hot-rolled 1050 steel with an ultimate tensile strength of Sut = 620 MPa. The manufacturing plant operates in an environment of 25° C, and a reliability of 99.99% is desired.

Answer 1

To begin we first calculate the maximum and min force acting on each cylinder rod. Since the setup is symmetrical we just need to calculate the force in just one rod we calculate the force in the rods on the left side Maxi Force- when the 400 kg part just rolls imports the maxi amount of force in the rods on the left conversely lowest in the rod on the right following fig illustrates the scenario let A be the point at which left rod connects to the conveyor and B be the point where right rod connects To calculate the force on rod A we apply moment eqn about point B 2 middot F_max times 1 = 4000 times 1.5 + 500 times 0.5 we write 2 middot F_max since Here are two rods on the left side = > F_max = 3125 N Mini Force following Fig illustarates the scenario