DESGIN OF LUG SUPPORTS BY BEDNAR BOOK

[jor1492]

Hello
I have a question about the example of support lug calcs using Pressure Vessel Design Handbook, 2nd Ed. by H. Bednar.

On page 156 for the Formula of the Maximun Stress in base plate, The formula uses a variable called "Beta".
Could someone explain me about this variable "Beta"? and where can I get it ?

thanks in advice

 

[pdiculous963]

Beta is the constant based on the geometry of the flat plate used in the formula for bending stress. This can be found in many handbooks, including Roark's Formulas for Stress and Strain.

 

[AWDMIKE]

After looking through the second edition of Bednar's book, it appears that he is using a reference to Roark's book and that is where beta comes from at the bottom of Bednar's example 3(a).
If you look in Roark's book at a rectangular plate, three edges simply supported, one edge free, uniform pressure over the entire plate (Roark's 7th Edition, Table 11.4, Case 2a), you can come up with the beta value of 0.72 for the plate dimension ratio of 1.25.
If you want to know where that came from, you can check the references in Roark or check one of Timoshenko's books. Maybe Theory of Plates and Shells.

 

[fegenbush]

Per the reference list on page 418 of Bednar, reference 46 is Roark's Formulas for Stress and Strain, 4th Edition.

 

[jor1492]

Thanks guys

I have another question. I am seeing the Roark book 7° edition and for the example of the bednar , it means that the width of the base plate, with value 15", is the simple supported edge and the width of the support under the base plate, with value 12", is the free edge.

Am I right?