FINITE ELEMENT INVESTIGATION OF INITIAL CLEARANCE EFFECT ON TUBE-TO-TUBESHEET JOINT STRENGTH
The tube-to-tubesheet joint strength is measured in terms of residual contact pressure between the tube’s outer surface and tubesheet hole surfaces. The joint integrity is affected by several design parameters, including the type of material and the initial radial clearance. To avoid weakening of jo...
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| Other Authors: | , , , |
| Format: | article |
| Published: |
2020
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| Subjects: | |
| Online Access: | https://eprints.kfupm.edu.sa/id/eprint/1707/1/P371.pdf |
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| Summary: | The tube-to-tubesheet joint strength is measured in terms of residual contact pressure between the tube’s outer surface and tubesheet hole surfaces. The joint integrity is affected by several design parameters, including the type of material and the initial radial clearance. To avoid weakening of joints due to excessive initial radial clearances Tubular Exchanger Manufacturer Association (TEMA) has set standards in which maximum over-tolerances are spelled out. The present work complements the experimental program on the effect of over-tolerance on heat exchangers tube-to-tubesheet joint strength. The finite element analysis first addressed the ligament effect on the residual stress in order to select a satisfactory sleeve diameter. Second, the initial clearance effect on contact pressure and percent tube wall reduction is performed. Results show that for low strain hardening materials the initial clearance effect is negligible. However, higher levels of strain hardening have a significant effect on residual stress and percent wall reduction. For low clearances, the finite element estimated residual contact pressure compared well with the analytical result and that inferred from the experimentally measured pull-out force. The variation of the percent wall reduction with initial clearance is found to be similar to that of the measured one. |
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