# Homework Help: Maximum Force Supported by Allowable Shear

1. Jan 22, 2012

### Bracketology

1. The problem statement, all variables and given/known data
The simple pin-connected structure carries a concentrated load P as shown. The rigid bar supported by structure AB and by pin at C. The steel strut Ab has a cross sectional area of .25in2 and a yield strength of 60ksi. The diameter of the steel pin at C is 0.375in and the ultimate shear strength is 54ksi. If a factor of safety of 2.0 is required in both the strut and the pin at C. determine the maximum load P that can be supported by the structure.

http://img707.imageshack.us/img707/21/photowb.jpg [Broken]

2. Relevant equations
$\Sigma$Fx=0
$\Sigma$Fy=0
$\sigma$allow=$\sigma$failure/(Safety Factor)
$\tau$allow=$\tau$failure/(Safety factor)
Safety Factor=$\sigma$failure/($\sigma$actual)
Safety Factor=$\tau$failure/($\tau$actual
Safety Factor=Pfailure/(Pactual)
Safety Factor=$\nu$failure/($\nu$actual)

3. The attempt at a solution
http://img196.imageshack.us/img196/5855/scan1dl.jpg [Broken]

I know the max allowable P at each point, but what I'm having trouble finding is the max P, based on those max loads at the points. How do I finish solving this?

Last edited by a moderator: May 5, 2017
2. Jan 22, 2012

### PhanthomJay

Unless you have not clearly drawn the diagram , it appears that the pin at B is not in double shear, so you may have divided by 2 once too often. What are the member lengths and structure dimensions? They are necessary to solve the problem. Which part of the structure controls the design? How would you then go about solving for the force in the pin at B?

3. Jan 22, 2012

### Bracketology

Oops, forgot to upload the picture so you can check my work.