Stress and strain question


by dblanche
Tags: strain, stress
dblanche
dblanche is offline
#1
May22-06, 04:13 AM
P: 5
The Ultimate tensile strength of steel is 470MPa.

Assuming a factor of safety of 5 the maximum working load an 8.00mm diameter round steel bar should support against gravity is?
Phys.Org News Partner Science news on Phys.org
Scientists pinpoint when harmless bacteria became flesh-eating monsters
Asian air pollution affect Pacific Ocean storms
Rocket leak delays space station delivery launch (Update)
Gokul43201
Gokul43201 is offline
#2
May22-06, 06:58 PM
Emeritus
Sci Advisor
PF Gold
Gokul43201's Avatar
P: 11,154
And the work you have done so far towards solving the problem is... ?

<see my signature>
dblanche
dblanche is offline
#3
May23-06, 04:39 AM
P: 5
I have used every formula that I can think of, i've used the following equations:



Stress= Force / Area
470 x 10E06 = force / 5.03 x 10E-05
Force = 23624.78 N

then multiply 23624.78 by the factor of safety being 5
= 118123.9 Newtons????????????????????????????


Don't really know how to do it, could you please give us some hints?????????????????????????

Gokul43201
Gokul43201 is offline
#4
May23-06, 07:14 AM
Emeritus
Sci Advisor
PF Gold
Gokul43201's Avatar
P: 11,154

Stress and strain question


Quote Quote by dblanche
I have used every formula that I can think of, i've used the following equations:



Stress= Force / Area
470 x 10E06 = force / 5.03 x 10E-05
Force = 23624.78 N
This is correct. You've calculated the maximum load.

then multiply 23624.78 by the factor of safety being 5
= 118123.9 Newtons?
There's a small error here. Should the allowable load be 5 times the maximum load ? What happens to the rod if you apply a load greater than the maximum load ?

Before you do any calculation involving numbers, first write down all the necessary equations using symbols to represent the various quantities involved. Plug in the numbers only after you've arrived at a final equation with the required unknown on one side, and all the knowns on the other.
dblanche
dblanche is offline
#5
May23-06, 05:58 PM
P: 5
No the allowable load would not be 5 times the maximum load, you divide this maximum load by 5 to give the maximum working load, which is 472.5 kg or 4724.96 Newtons..................................

Thanks for your help


Register to reply

Related Discussions
Finding the max shear stress at a point on a plate (with a hole) Classical Physics 1
Stress vs. Strain Engineering, Comp Sci, & Technology Homework 2
Stress and Strain Introductory Physics Homework 20
stress strain Engineering, Comp Sci, & Technology Homework 2
stress/strain/elongation question Introductory Physics Homework 2