Effects of Analysis Method, Bolt Pre-Stress, and Cover Plate

Thickness on the Behavior of Bolted Flanges of Different

SizesStatus Report 3

Chris WowkMANE 6970

Master’s Project

All Analyses Completed Technical Content Sections Populated Comments Incorporated

To Go Finalize Appendices Abstract Acknowledgements

Status

Waters and Schneider’s (1969) method for analyzing cover plate/flange joints extended to determine flange separation

Analytical Solution

FEA Analyses

Solid Element Model Shell/Beam Element Model

Cases RunNPS Size

Cover Thickness

Bolt Pre-Stress 0Pressure

Load25% Yield

80% Yield

0Pressure

Load25% Yield

80% Yield

0Pressure

Load25% Yield

80% Yield

0Pressure

Load25% Yield

80% Yield

Radial Beam Theory

Solid Element FEA

Shell Element FEA

Radial Beam Theory

Appendix Y Equations

Solid Element FEA

Shell Element FEA

Radial Beam Theory

Appendix Y Equations

Solid Element FEA

Shell Element FEA

Radial Beam Theory

Solid Element FEA

Shell Element FEA

Joint Separation Along Length

Radial Location of Contact

Stress In Center of Cover

Maximum Joint Separation

AnalysisMethod

t1 0.5*t1 2*t1

4"

t2

16"

Shell/Beam FEA predicts much lower joint separations (all cases)

Joint Separation decreases as cover thickness increases

Greater separation for larger size flange at low preloads. Approaches similar limit as smaller joint as preload increases

Joint SeparationResults

Great agreement between analysis methods for 4 NPS joint

Contact location cannot be normalized to compare different sized joints

Normalized Location of Contact

RBT and Appendix Y equations appear to approach a limit

FEA solutions show increase at high preloads

Stress decreases as cover thicknesses increases

Stress In Center of Cover

FINISH – ASAP!!

Schedule Going Forward

ASME Boiler and Pressure Vessel Code, Section VIII – Rules for Construction of Pressure Vessels, 2013 Edition, Appendix Y.

Galai, H and Bouzid, A.H, “Analytical Modeling of Flat Face Flanges with Metal-to-Metal Contact Beyond the Bolt Circle,” Journal of Pressure Vessel Technology, Vol 132, 2010.

Schneider, R.W, “Flat Face Flanges with Metal-to-Metal Contact Beyond the Bolt Circle,” Transactions of the ASME, Vol 90, 1968, pgs 82-88.

Waters, E.O and Schneider, R.W, “Axisymmetric, Nonidentical, Flat Face Flanges with Metal-to-Metal Contact Beyond the Bolt Circle,” Journal of Engineering for Industry, Vol 91, 1969, pgs 615-622.

References