Dear Experts,

In Equivalent solid plate method for Design of Tubesheet,based on the graphs of ligament efficiency v/s E*/E ,effective Elastic modulus is calculated,based on which calculations for thickness of tubesheets.

Can anyone plz explain me the basis behind this PLOTS...???...and also,How it depends on the Pattern of the holes(i.e equilateral Triangular or rectangular).....?????????????

Thanks for your reply,in advance.

There are enormous literature on this topic. The weakening effect of hole is accounted by using modified elastic constants. The concept is to have same deflection; i.e the deflection that can be obtained using an equivalent solid plate is same as that of real deflection of perforated plate.
Sampson's effective elastic constants are based on photoelastic experiments; The curves are evolved (to the best of my knowledge) mainly based on photoelastic experiments and rigourous theoretical calculations. There are papers from Meijers, Langer, Downell, Porowski etc;
Subsequently, with Finite element and advanced computing capabilitee, people have verified the elastic constants and research is in progress in many areas of perforated plates including creep.
The curves are different not only based on traingular or square pattern but also on thickness to pitch ratio more than / less than two (UHX of asme sec Viii Div.2).

My M.TECH thesis from IIT MADRAS , INDIA is on this topic. I hope this is adequate to start with

R.SRINIVASAN
DESIGNER FROM INDIA

_________________
R.SRINIVASAN
Sr. VICE PRESIDENT
Head, Design and Engineering
PED,ISGEC,
YAMUNANAGAR
HARYANA -135001
INDIA