Table of Contents
What is a SPO flange?
SPO Compact Flanges incorporate two independent metal to metal sealing mechanisms. The seal ring is a non-load carrying seal which is unaffected by flanges loads, a requirement of DNV-OS-F201.
What is compact flange?
A compact flange, similar to a swivel ring flange, is a two-piece constructed flange used extensively for offshore pipelines, offshore industry applications and onshore and sub-sea applications. Its double sealing action prevents hydrocarbon releases to address health and safety issues and concerns.
What is compact and non compact section?
A compact section means that the section can achieve the plastic moment with local buckling on the web or the flange. But a noncompact section is a section that can reach the yields for the lower and bottom fiber only without causing local buckling to the web or the flange.
What is compact steel?
All cross sections of the compression member can be divided solely based on the type of steel used and dimension of the cross section. The slenderness ratio is major factor that influences the flexural capacity of the braced beams. If a beam has very small slenderness ratio, it is called as compact section.
What is local buckling?
Local buckling is a failure mode commonly observed in thin-walled structural steel elements. Even though its effect on their behaviour at ambient temperature conditions is well documented and incorporated in current design codes, this is not the case when such elements are exposed to fire.
What is slender section?
Explanation: Slender or class IV sections are cross section in which local buckling occurs even before the yield stress is attained in one or more parts of the cross section.
What is slender plate?
Members with plates having b/t ratios greater than lr are said to be “slender” and exhibit elastic buckling behavior. Their compressive strength is limit by elastic buckling.
What is the difference between global and local buckling?
Global buckling is classical Euler buckling. This has to do with the “global” cross-section properties (EI) and the beam/column unbraced length “L”. Local buckling is the buckling of an unstable portion of a cross-section. You could call it cross-section buckling.
What is ratio for local buckling?
The subject includes local buckling parameters, namely the slenderness ratio for the flange λF= (Bf/2*Tf) and the slenderness ratio for the web λw= (h/tw), for the plastic stage, the first local buckling parameter, and for limiting slenderness which is the second local parameter.
What is Web buckling?
Web buckling occurs when intensity of vertical compressive stress near centre of section becomes greater than the critical buckling stress for the web acting as a column.
How many types of buckling are there?
These four forms elastic buckling are the saddle-node bifurcation or limit point; the supercritical or stable-symmetric bifurcation; the subcritical or unstable-symmetric bifurcation; and the transcritical or asymmetric bifurcation.
What is secondary buckling?
Secondary buckling refers to any other mode of buckling that is not primarily flexural. The straight, thin walls of an open section may distort with translation and rotation in its plane.
Why hammering is done in rivet?
Explanation: Holding red hot rivet at shop head end, hammering is made. It results into expansion of rivet to completely fill up the rivet hole and also into formation at driven head.
What is difference between bending and buckling?
As we know both bending and buckling is caused in a structural member due to applied load. When transverse load is acting perpendicular to neutral axis of structural members is known as bending. Bending in structural member is 2 types sagging and hogging.
What is diagonal buckling?
4.6. Rating. Unlock Full Solution (Free) For a Plate Girder, diagonal buckling of the web occurs when the ratio of clear depth to the thickness of the web exceeds 85.
What is a SPO Compact flange?
SPO Compact Flanges are DNV type approval qualified and available in swivel design for all sizes listed within each pressure class. SPO Compact Flanges are both smaller and lighter than conventional API and ASME flanges, including swivel ring flanges.
Why vector SPO® CF flanges?
The Vector SPO® CF is the only flange meeting the strict design requirements in DNV-OS-F201 (Dynamic Risers) and ISO 13628-7. A reliability evaluation report from DNV (DNV report 12FQG2F-6) concludes that the SPO® CF is considered amongst the best welded connections with respect to leakage probability.
How long does the vector SPO Compact flange last?
No operational leakage for more than 400.000 flange-years of operation, mainly thanks to the 100% static sealing conditions. The Vector SPO compact flange has two independent seals in series together with an additional environmental seal.
What are the different types of flanges available?
Flanges are available from standard forging or casting with seal rings in compatible high strength forged materials. The seal rings are normally coated with PTFE or alternatively with MoS2 or graphite based coating. Non-coated seal rings can be used, but requires use of suitable lubrication of seal groove.