REPORT1.0 INTRODUCTIONThe research objectives of this subtask are: Evaluatethemassdiffusionusingnumerical simulationonthePEandPA11pipelinesections and compare the variations in the amount of gas diffused Obtainaninsight intothedegradationof thephysical propertiesof thematerials ofpipelineand map the concentration into another simulation Conduct the !E" creep analysis in the ne# simulation to #hich the concentration dueto mass diffusion has been mapped$n the previous report% a simulation of the mass diffusion of methane has been simulated for particular conditions& The simulations give us a clear picture on the variation of the gas concentration along the radial direction of the pipeline and translation of the mass diffusion of gas in the pipeline to e'uivalent temperature distribution in the piping system&This report #ill present another method to map the concentration of hydrocarbon after the mass diffusion is done by using the A(A)*+ soft#are& Then the !E" analysis has been done on themodel #hich no# consists of the effects of diffusion of the gas&2.0 MASS DIFFUSION IN PIPELINESThe mass diffusion of various gases like hydrogen% methane and carbon dio,ide has been a greatconcern for the increasing deterioration of the life of the polymer pipelines used& The sorption ofgasses in polymer membranes depends strongly on the nature of the polymer% the pressure andtemperature& $n this section of report there is an alternate method that has been studied to map theconcentration of the diffusion to another model and the creep !E" analysis has been done& $nprevious report% #ehavetriedtousethethermal-mass diffusionanalogies tocreatealinkbet#eenthemass diffusionandtemperaturediffusion& This is re'uiredbecauseoncemassdiffusion is done #e #ill not be able to do further analysis on it to obtain the post diffusionproperties in the materials& Thus it is being converted to an e'uivalent temperature distributionand then subjected to mechanical testing% but it #as not possible to do comple, !E" analysisin a thermo-coupled manner hence this ne# method has been tried out&3.0 METHODOLOGIES FOR ANALYSIS OF DIFFUSION EFFECTMETHOD 1: THERMO-DIFFUSION ANALOGY$n the previous report a detailed analysis of mass diffusion of gases #as done for different casesand #as visuali.ed& $n this section #e are have made effort to convert the diffusion to e'uivalenttemperature diffusion& This is done as there is no possibility of doing a post diffusion analysis inthe simulation soft#are& /ence the mass diffusion is converted to a temperature simulation andthen a mechanical analysis is done to obtain the change in properties& !or no# the mass diffusion is done and e'uivalent temperature analysis is done by using directanalogy #hich is e,plained in the upcoming sections& $n practice% the thermal diffusion or heattransferfunctioncanbeutili.edtosimulatemassdiffusionthroughathermal-massdiffusionanalogy&The conduction heat transfer e'uation 011 can be described by !ourier2s la#%#here T and ' are the temperature 3 and the heat flu, 4 m56% respectively7 inverted delta is thegradient operator7 and k is the thermal conductivity 4m51 351 for isotropic thermal diffusion% andits dependency on temperature is negligible in most cases&Assuming no internal heat generation% the energy balance yields the governing e'uation 061 ofheat transfer as#here 8 and Cp are the density kg m59and the specific heat : kg51351% respectively& Assumingthat thermal conductivityis uniform% E's&1and6yields the #ell-kno#nheat conductione'uation 091 as#here ; is the thermal diffusivity m6 s51 defined as ; : Concentration distribution for PE pipeline5.2 PART 2: XFEM CREEP ANALYSISOnce the mass diffusion is translated to the ne# model the Aba'us soft#are is used to do !E"creepanalysis& $npreviousreports% important parameterstodefinethemodel in Aba'usandparameter values% final geometry and simulation results are mentioned&$n this report% the complete model is analy.ed and the !E" creep analysis is carried out forlocating the crack propagation and visuali.ing its effect& The same results can be obtained usingonly one-half geometry and lesser number of elements #ith the help of appropriate boundaryconditions&The model #as mesh #as imported from the previous analysis of mass diffusion along #ith thenode-to-nodesimulationresults& Tetelements#ereusedasbodyhadacurvedsurface&Aftermeshing% material model #as assigned& The parameter2s values chosen to define model are asunder& "od& of Elasticity J 1KLL "Pa Poisson2s Hatio J L&> Tensile +trength% *ltimate J AM&N "Pa Tensile +trength% Eield J >> "Pa Tangent "od& J 6&@O of "od& of Elasticity CP"% Criterion J "a,& Principal +tress CP"% Ialue J @6 "Pa CP"% ?amage Evolution J Energy% E,ponential +oftening CP"% !racture Energy J A6L 3:=m6Dater% (oundary conditions #ere given& The boundary conditions are given to constrain the model in the ?O!2s #hich are as follo#s: (Cs can only be applied in directions that the element has ?o!2s& The flat surfaces at the ends of pipe are completely constrained& There is pressure load applied to get a solution&As the diffusion of gas causes degradation in the properties of the material% the t#o layer of thepipearegivenadecreaseintheirpropertiesofA&AKOand9&99Oforinnerandouterlayerrespectively& The figure @ and A sho#s the t#o layer defined for different material properties&!igure @& !irst layer #ith different material properties!igure A& +econd layer #ith different material properties!igure K& "apped Geometry!igure M& DoadingThe red dots sho#s the (oundary conditions applied and the arro#s sho# the pressure appliedon each of the nodes& !igure N& (oundary Condition!igure 1L& +tress Plot #ithhout mass diffusion!igure 11& ?isplacement Plot #ithhout mass diffusion!igure 16& +tress Plot #ith mass diffusion!igure 11& ?isplacement Plot #ith mass diffusionA pressure load #as applied and the results #ere obtained% further analysis is being conducted to find the critical parameters #hich affect the crack propagation& $n future report% an detailed analysis #ith parametric study can be e,pected& 5.0 FUTURE DIRECTION OF RESEARCHThe future plan is to find various factors for #hich affect the crack propagation due to creep in the pipelines& The mapping of concentration obtained from mass diffusion of the polyethylene and polyamide11 has been successfully transferred to another model and the !E" analysis is done& The simulation presented in this reported only the primitive and #ould be further research on ho# to better them to bring accurate results& As future #ork #e have planned to do a parametric analysis on the various prime factors affecting the crack gro#th&REFERENCESQ1R ?uncan% (ruce% :eannie *r'uhart% and +imon Hoberts& Hevie# of measurement andmodellingof permeationanddiffusioninpolymers& "iddlese,% *3: Bational PhysicalDaboratory% 6LL@&Q6R !laconneche% (&%:&"artin% and "&/&3lopffer&SPermeability% diffusion andsolubilityofgases in polyethylene% polyamide 11 and poly 0vinylidene 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