224813666-Pipe-Stress-Analysis.ppt

PIPE STRESS ANALYSIS

STRESS ANALYSISINTRODUCTIONOBJECTIVESPURPOSEREQUIREMENTSPROCEDURE CONCLUSION

INTRODUCTIONWHAT IS STRESS?Stress=Applied force/Cross Sectional AreaStrain=Change in dimensions/Original dimensions.Stress of a material is the internal resistance per unit area to the deformation caused by applied load.

STRESS-STRAIN CURVE

IMPORTANCE OF PIPE STRESS ANALYSISUniform Piping LayoutSupport LocationsCalculation of Nozzle Loadings,Support Loadings,Stress,Displacement,Forces,Moments.Pipe Flexibility

OBJECTIVESWhat is STRESS ANALYSIS: It provides the necessary technique for Engineers to design piping systems without overstressing & overloading the piping components & connected equipment.

OBJECTIVES: The Layout & Design of Piping shall be made to prevent the followings:

1.Piping Stress in excess of those permitted by the Codes2.Leakage at Joints3.Excessive forces & moments on connected Equipments.4. Excessive Stresses in the piping supporting elements5. Excessive with thermal Expansion & Contraction

FORMAL ANALYSIS IS NOT REQUIREDDuplicates or Replaces without significance change,a system operating with a successful service records.Can readily be judged adequate by comparison with previously Analyzed systems.Thumb Rule: D=Outside Diameter of the Pipe in mm y =Resultant of total displacement Strains in mm L=Developed length of Piping between Anchors in m U=Anchor distance,straight line between Anchors in m K1=208000 Sa/Ea in (mm/m) Sa=Allowable Displacement Stress in MPa Ea=Reference Modulus of Elasticity in MPaDy/(L-U)

PURPOSESafety of Piping & Piping ComponentsSafety of Connected Equipment & Supporting StructurePiping Deflections are within the Allowable limits

STRESS ANALYSIS FLOW CHARTPreparation of Critical Line ListDocuments(Isometrics)Generating ReportsAnalysis(Stress,Loads,Displacement)Run,Checking the Errors & WarningsInputs in the SoftwarePipe Stress Analysis(Software)

REQUIRMENTSCAESAR-II,AUTO PIPE,PIPE FLEX,CAE PIPE(Stress Analysis Software)Critical Line ListGADs(General Arrangement Drawing)P & Ids(Process & Instrument Drawing)IsometricsPMS (Piping Material Specification)Others(Dimensions,Valve Weights)

PROCEDUREMODELLINGSTRESS ANALYSISSTRESS REPORTS

STRESS ANALYSISStatic AnalysisDynamic AnalysisSlug Flow Analysis

STATIC ANALYSISBuried(Underground)Flange Leakage TestAPI 610(Centrifugal Pumps)API 617(Centrifugal Compressor)API 661(Air-Cooled Heat Exchangers)API 560(Fired Heaters for general Refining Services)

STATIC ANALYSISWRC 107/297(Vessel Stress & Nozzle Loadings) B 31.G(Remaining Strength of Corroded Pipelines)Expansion Joint RatingAISC(American Institute of Steel Construction)NEMA SM23(Turbines)SIFs Intersections & SIFs Bends HEI Standards(Rotating Equipment Nozzle)

STATIC ANALYSISStress ReportsRestraint Summary ReportsDisplacement ReportsSelection of SupportsWind,Wave,Earthquake Consideration

DYNAMIC ANALYSISNatural Frequency CalculationHarmonic AnalysisResponse Spectrum AnalysisTime History Analysis

SLUG FLOW ANALYSIS

Spectrum Method

STRESS CATEGORIESPrimary StressSecondary StressPeak Stress

PRIMARY

1.Sustained External forces & moments

2.Prevent plasticdeformation & bursting

STRESS CATEGORIES

SECONDARY

1. Local yielding and minor distortion can satisfy the conditions which caused the stress to occur. 2.Thermal stress PEAK

1.The additional stresses due to stress intensification in highly localized area.2.Stress due to notch effect (Stress concentration)

ALLOWABLE STRESSSmax=1.6(Sc+ Sh)Sa= F(1.25 Sc + 0.25 Sh)Sa=Allowable StressSc=Cold Allowable StressSh=Hot Allowable StressF=Stress Range Reduction factor for Cyclic Conditions CYCLES F 7000 and less1.0 (20Years)7000 to 140000.914000 to 220000.822000 to 450000.745000 to 1000000.6100000 and over0.5

Classification of LoadsPrimary Loads 1.Sustained Loads(Pressure & Weight) 2.Occasional Loads(Earthquake & wind)Expansion Loads(Displacement,Thermal Expansion,Seismic Anchor movements,Building Settlement)

CODESB31.1(Power Piping)B31.3(Process Piping) Petroleum Plant Refineries Plant Chemical Plant Pharmaceutical Plant Textile Plant Paper Plant Semiconductor & Cryogenic PlantB31.4(Pipeline Transportation)B31.5(Refrigeration Piping) B31.8(Gas Transmission & Distribution System)

SUPPORTSRestraintsGuideLimit StopsAnchorHangerTrunnion

PIPE FLEXIBILITY The Purpose of Piping Flexibility Analysis is to produce a Piping Layout that cause neither excessive stresses nor excessive end reactions.

PIPE FLEXIBILITYParameters to be Considered for Flexibility Analysis:-The Appropriate Code that applies to the system.The Design Pressure and Temperature.The Type of material.The Pipe Size and Wall Thickness of each Pipe Component.The Piping Geometry including movements of Anchors and Restraints.The Allowable Stresses for the design conditions set by appropriate Code.Limitations of forces and moments on Equipment Nozzles set by API, NEMA or the equipment manufacturers.

CAESAR II 5.00 Interface

CAESAR II 5.00 InterfaceTear Away Indicator (double-click anywhere in the box to activate)Aux Screen Selector (Not tearable, but left-clicking and dragging will alter the order. Order change is not persistent)Thumbtack for input pane. Clicking will scroll the input into the frame, giving more space for the plot.Input pane caption bar. Double-clicking will float the pane for CAESAR II Classic ModeToolbar customization drop-down

CAESAR II 5.00 InterfaceNavigation buttons First, previous, next, lastDuplicate last elementThese buttonstoggle these for each selected item(use the Selection Operator or right-click on something on the plot Perform the List/Block operations

CAESAR II 5.00 InterfaceDrop down arrow allows selective opening or closing of individual listsIndividual lists may be opened, closed, or undocked in their own windows.


Design-your-own spreadsheet with tearables


Design-your-own spreadsheet with tearablesMini-spreadsheet, containing only key data.


Graphic editingSelect element and choose operation


Graphic editing


Graphic editingAdd restraints (or any other auxiliaries).

CAESAR II 5.00 InterfaceNavigation buttons First, previous, next, lastDuplicate last elementThese buttonstoggle these for each selected item(use the Selection Operator or right-click on something on the plot Perform the List/Block operations

CAESAR II 5.00 InterfaceDrop down arrow allows selective opening or closing of individual listsIndividual lists may be opened, closed, or undocked in their own windows.


Design-your-own spreadsheet with tearables


Design-your-own spreadsheet with tearablesMini-spreadsheet, containing only key data.


Graphic editing


Graphic editingSelect element and choose operation


Graphic editing


Graphic editingAdd restraints (or any other auxiliaries).


Graphic editing


Walk-through


Interactive error checking


Interactive error checkingActivate Error CheckerOutput from Error Check (selecting each line with a node number will highlight that element on the plot and switch the piping input screen (or floating parts) to the appropriate page). Errors are displayed in red, Warnings are green and Notes are blue. Clicking on a column header will sort based on the data in that column.)Summary from Error Check (only updates when error checking is complete)Input/Error selector (holding left button and dragging will detach windows)Closes Error Check output (re-running will re-open)


Interactive error checking

Automatic Generation of Stress IsometricsIsos developed using de-facto standard Isogen

Piping Code ChangesNew codes EN-13480, GPTC/192, Z662 Ch 11

Piping Code ChangesMAJOR revisions B31.3, B31.8

Piping Code ChangesMinor revisions B31.1, B31.5, B31.11, ASME NC, ASME ND, CODETI, TBK 5-6, API-610

MODELLING

CONCLUSIONPipe Stress Analysis is Very important & Useful for Piping in Petroleum Refineries,Chemical,Pharmaceutical, Textile, Paper, Semiconductor & Cryogenic Plants as also in Off Shore & On Shore for Safe Working.

THANK YOU FOR YOUR PATIENCEPrepared By BABASHIS RAYGURU.