How to stress analyse for underground pipingFull description
Description : FRP Analysis in Caesar-II
Descripción: How to stress analyse for underground piping
FRP Analysis in Caesar-II
Stress Analysis of Centrifugal Compressor Connected Piping SystemsFull description
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TutorialFull description
Piping Stress AnalysisDescripción completa
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Descripción: Caesar II mainly used for pipe stress analysis and water hammer is one of the frequent cases to be analysed as per this document
Stress Analysis of GRP/GRE/FRP piping system using CAESAR II GRP products being proprietary the choice of component sizes fittings and material types are limited depending on the supplier! Potential GRP "endors need to be identified early in design stage to determine possible limitations of component a"ailability! #he mechanical properties and design parameters "aries from "endor to "endor! So it is utmost important that before you proceed for stress stress analy analysis sis of such such system systems s you must must finali finalize ze the GRP/FR GRP/FRP/G P/GRE RE "endor "endor!! Se"era Se"erall parameters $Fig! %& for stress analysis ha"e to be ta'en from "endor! Stress analysis of GRP piping system is go"erned by IS( %)*+, part -! #he GRP material being orthotropic the stress "alues in a.ial as ell as hoop direction need to be considered during analysis! #he folloing article ill pro"ide a guideline for stress analysis of GRP piping system in a "ery simple format! 0efore you open the input spreadsheet of CAESAR II communicate ith the "endor through mail and collect the folloing parameters as listed in Fig!%!
Fig!%1 Parameters re2uired for stress analysis of GRP piping 1 /
#he "alues shon in the abo"e figure is for e.ample only! Actual "alues ill differ from "endor to "endor! #he abo"e parameters are shon for a *3 pipe! Inputs Required for Analysis: For performing the stress analysis of a GRP piping system folloing inputs are re2uired1
GRP pipe parameters as shon in Fig! %! Pipe routing plan in form of isometrics or piping GA! Analysis parameters li'e design temperature operating temperature design pressure fluid density hydro test pressure pipe diameter and thic'ness etc!
Modeling in CAESAR II: (nce all inputs as mentioned abo"e are ready ith you open the CAESAR II spreadsheet! 0y default CAESAR ill sho 0 -%!- as go"erning code! 4o refer to Fig! , and change the parameters as mentioned belo1
Fig! ,1 #ypical CAESAR II input spreadsheet for GRP Piping
Change the default code to IS( %)*+,! Change the material to FRP $CAESAR 5atabase 6aterial 4umber ,7& as shon in Fig! ,! It ill fill fe parameters from CAESAR database! 8pdate those parameters from "endor information! Enter pipe (5 and thic'ness from "endor information! 9eep corrosion alloance as 7! Input #% #, P% :P and fluid density from line list! 2 /
8pdate pipe density from "endor information sheet if "endor does not pro"ide density of pipe then you can 'eep this "alue unchanged! (n the right side belo the code enter the failure en"elop data recei"ed from "endor! Enter thermal factor;7!<= if pipe is carrying li2uid enter 7!< if the pipe carries gas! After you ha"e mentioned all the highlighted fields proceed modelling by pro"iding dimensions from the isometric/piping GA draing! Add supports at proper location from isometric draing! 4o clic' on en"ironment button and then on special e.ecution parameter! It ill open the indo as mentioned in figure -!
Fig! -1 #ypical Special E.ecution parameters Spreadsheet! 4o Refer Fig! - and change the highlighted parts from a"ailable data!
Enter the GRP/FRP co>efficient of thermal e.pansion recei"ed from "endor Calculate the ratio of Shear 6odulus and A.ial modulus and input in the location! In FRP laminate 'eep the default "alue if data is not a"ailable! After the abo"e changes clic' on o' button! ?hile modelling remember to change the (5 and thic'ness of elbos/bends! 3 /
Modeling of Bend and Tee Connections: 6odeling of bends is a bit different as compared to CS piping! 4ormally bend thic'nesses are higher than the corresponding piping thic'ness! Additionally you ha"e to specify the parameter $Ep#p&/$Eb#b& hich is located at the 0end au.iliary dialogue bo. as shon in Fig! )! #his "alue affects the calculation of the fle.ibility factor for bends! ?hen you clic' on SIF and #ee bo. in CAESAR II spreadsheet you ill find that only three options $#ee @oint and ualified #ee& are a"ailable for you as shon in Fig! )! Each type has their on code e2uation for SIF calculation! 8se the proper connection Budiciously! It is alays better to use SIF as ,!- for both inplane and outplane SIF to adopt ma.imum conser"ati"e approach!
Fig! )1 6odeling of Elbos and #ees for FRP/ GRE piping Load Cases for Analysis: IS( %)*+, informs to prepare - load cases1 Sustained Sustained ith thermal and :ydro test! So accordingly the folloing load cases are sufficient to analyze GRP piping system
#he e.pansion load cases are not re2uired to create as no alloable stress is a"ailable for them as per the code! ?hile preparing the abo"e load cases you ha"e to specify the occasional load factors for each load case in load case options menu as shon in Fig! =! IS( %)*+, considers hydro test case as an occasional case! In higher "ersions of CAESAR II softare $CAESAR II>,7%* and CAESAR II> ,7%& these load factors are ta'en care by default! So you need not enter the "alues! #he option of these "alues entry ill be a"ailable only if you define the stress type as occasional for those softare "ersions! 4 /
Fig! =1 Specifying (ccasional oad factors in CAESAR II for GRP/FRP piping system #he default "alues of occasional load factors are %!-- for occasional case %!,) for operating case and %!7 for sustained case! #his occasional load factors are multiplied ith system design factor $normally 7!*& to calculate the part factor for loading f,! For abo"eground GRP piping the abo"e load cases are sufficient! 0ut if the ine is laid underground then to different CAESAR II files are re2uired! (ne for sustained and operating stress chec'! And the other for hydro testing stress chec' as the buried depth during hydro testing is different from the original operation! Also buried depth may "ary in many places! So CAESAR II modeling should be done meticulously to ta'e care ith e.act effects! For buried modeling one need to split the long lengths into shorter elements to get proper results! Element length of - m or less is ad"isable! Sometimes buried model contains slope those sloped are re2uired to model properly to get accurate results! Output Results: 0oth stress and load data need to be chec'ed for GRP piping! 4ormally the stresses are more than +7H $E"en sometimes it may be as high as ++!+H&!
