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Pressure Vessels

2 tools in the Mechanical Design area.

Pressure Vessel

Stresses and code thickness of a cylindrical or spherical pressure vessel in three parts chosen by checkboxes: the thin-wall membrane stresses (hoop and longitudinal, von Mises, the t/r limit, the end-cap force and the bolt load of a bolted head), the thick-wall Lamé solution for internal and external pressure (radial, hoop and axial stress through the wall with a chart, the maximum shear and von Mises stress at the bore, the first-yield, full-plastic and Faupel burst pressures, the wall required for an allowable stress), and the ASME Boiler and Pressure Vessel Code Section VIII Division 1 rules (UG-27 shell thickness and MAWP, UG-32 hemispherical, 2:1 ellipsoidal and torispherical heads with the Appendix 1-4 factors, corrosion allowance, joint efficiency, mill undertolerance and the UG-99 hydrostatic test pressure). The default is a 48 in inside-diameter, 0.5 in thick SA-516 Grade 70 vessel (S = 20,000 lb/in²) at 120 lb/in² with E = 0.85 and 2:1 heads: hoop stress 5.76 ksi (Hibbeler's Example 8.1 geometry), UG-27 required thickness 0.171 in plus a 1/16 in corrosion allowance, MAWP 306 lb/in².

1 worked example reproduced, listed on the tool page.

Bolted Flange Joint

Design check of a bolted flanged joint with a ring-type gasket by the method of ASME Boiler and Pressure Vessel Code Section VIII Division 1 Mandatory Appendix 2 (the Taylor Forge method of Waters, Rossheim, Wesstrom and Williams): integral weld-neck, loose hubbed (lap joint) and loose ring flanges; the effective gasket width and reaction diameter from the facing rule; the operating and gasket-seating bolt loads W_m1 and W_m2 from the gasket factors m and y, the required and actual bolt areas (root areas of Unified and ISO threads), the bolt stresses and spacing; the flange moments from the end, face and gasket forces and their arms; the K, T, U, Y, Z factors and the hub factors F, V, f (or F_L, V_L) by the Code's closed forms; the longitudinal hub, radial and tangential flange stresses at both conditions against the 1.5 S_f and S_f limits; the rigidity index and flange rotation; a bolt-torque table; charts of the stresses against flange thickness and of the hub factors; a section figure with the loads. Default: an NPS 8 class 150 weld-neck flange (illustrative dimensions) with a spiral-wound gasket at 150 lb/in².

1 worked example reproduced, listed on the tool page.

Other Mechanical Design sections

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