COMPLIANT COMPONENT FOR SUPPORTING BEND STIFFENERS

Abstract

The present invention comprises a structure with the same external geometry as a generic hook, but with a topology (internal structuring) that allows a greater distribution of deformation energy to all elements of the part, with load transfer to other less stressed regions. When the present invention is subjected to a loading, said flexible parts deform in a pre-specified manner, transferring part of a loading that would be excessive in a given region to another less loaded region, without any power supply or external interference. In this way, the deformation pattern that occurs in the present invention relieves stresses where they are greatest and, at the same time, provides flexibility (compliance), more adequately distributing coupling loads between the various fastening components.

Claims

1. A compliant component for supporting bend stiffeners, comprising a non-massive component with at least an upper portion, a lower portion, a compliant member, an opening end, an anterior contact rod, a posterior contact rod, wherein the upper portion and the lower portion are connected by at least one anterior element and at least one posterior element.

2. The compliant component for supporting bend stiffeners according to claim 1, wherein the upper portion preferably consists of a preferably massive region with at least one through hole and/or blind hole or elements for fastening in a riser support system, such as a bellmouth.

3. The compliant component for supporting bend stiffeners according to claim 1, wherein the central region and the lower portion comprises hollow spaces to allow the movement of the compliant members.

4. The compliant component for supporting bend stiffeners according to claim 1, wherein the compliant member comprises a curved extension that projects from the upper part of the lower portion to the central region, located between the anterior and posterior rods.

5. The compliant component for supporting bend stiffeners according to claim 1, wherein the compliant member comprises a displacement restriction region, positioned between the anterior and posterior rods, an opening end located immediately below the discontinuity of the anterior face, and a locking end located above the anterior rod.

6. The compliant component for supporting bend stiffeners according to claim 1, wherein the upper portion and the lower portion have different shapes and/or curvatures to suit different fastenings.

Description

BRIEF DESCRIPTION OF FIGURES

[0040] In order to obtain a better understanding of the features of the present invention and, according to a preferential practical embodiment of this invention, following to the description there is attached a set of drawings where, in an exemplified way, although not limiting, its operation is represented:

[0041] FIG. 1 shows a current usual approach of the components involved in the flexible riser support system (BSN-900E), where there are indicated: (A) components coupled for operation; (B) Detailing for the components of the Bell Mouth. In FIG. 1, there are: (I) Flexible riser top connector, (II) Flexible riser, (III) Lower riser counter, (IV) I-tube, (V) Bell Mouth, (VI) Stiffener (Bend Stiffener), (VII) Bend Stiffener Helmet, (VIII) DOG, (IX) Axis, (X) Ring and Dog Holder Plates;

[0042] FIG. 2 shows a representation of the different regions that make up a DOG, currently used in the BSN-900. In FIG. 2, there are: (I) Hole for coupling the locking system, (II) Hole for coupling the support shaft, (III) Posterior face, (IV) Anterior face, (V) Heel, (VI) Lower face, (VII) Center of curvature, (VIII) Support face, (IX) Coupling region, (X) Locking region, (XI) Body, (XII) Heel, (XIII) Lower region, (XIV) Curvature region, (XV) Support face region;

[0043] FIG. 3 shows a simplified representation of the acting forces normally used for dimensioning the DOGs, where there are indicated: (A) loading (T) and global reaction (H); (B) distribution of strengths in the support system as a bending moment M and a shear C;

[0044] FIG. 4 shows the graph of the result of the preliminary study of the increase in flexibility in the assembly of DOGs, showing the reduction in the level of characteristic fatigue stress;

[0045] FIG. 5 shows the present invention in one of its preferred configurations based on Compliant Mechanism (CM) for bell mouths, considering the BSN900E model, where: (A) frontal view and (B) isometric view;

[0046] FIG. 6 shows the side view of the present invention in its preferred configuration emphasizing the Compliant Mechanism (CM);

[0047] FIG. 7 shows the side view of the present invention, representing the operation of the Compliant Mechanism (CM) under reverse (left) and normal (right) vertical strengths;

[0048] FIG. 8 shows the side view of the present invention, representing the operation of the Compliant Mechanism (CM) under reverse (left) and normal (right) horizontal strengths.

DETAILED DESCRIPTION OF THE INVENTION

[0049] With reference to FIGS. 5, 6, 7, and 8, the present invention comprises, in its preferred configuration, a non-massive component with at least an upper portion (1), a lower portion (2), a compliant member (3), an opening end (3b), an anterior contact rod (4), a posterior contact rod (5), and wherein the upper portion (1) and the lower portion (2) are connected by at least one anterior element (10) and at least one posterior element (11).

[0050] The upper portion (1) preferably consists of a preferably massive region with at least one through hole and/or blind hole, or elements for fastening. The central region, where the compliant mechanism is located, and the lower portion (2) comprise hollow spaces in order to allow the movement of the compliant members (3).

[0051] In addition, the upper (1) and lower (2) portions may have geometric variations such as different shapes and/or curvatures to suit different fastenings, provided that they maintain the central portion of the compliant component substantially similar to the preferred presented shape.

[0052] The compliant member (3) comprises a curved extension that projects from the top of the lower portion (2) to the central region, located between the anterior (4) and posterior rods (5). Said member (3) comprises a displacement restriction region (3a), which is positioned between the anterior (4) and posterior (5) rods, an opening end (3b), located immediately below the discontinuity of the anterior face (10), and a locking end (3c), located above the anterior rod (4).

[0053] The anterior rod (4) and the posterior rod (5) comprise extensions that depart from the anterior (10) and posterior (11) element, respectively. The anterior element (10) presents a discontinuity in the upper portion of the opening end (3b), which allows a great amplification of the movement imposed by the Helmet on the support face of the DOG, as can be seen in FIGS. 7 and 8.

[0054] However, when this movement occurs, the curved element acting internally to the DOG, called the compliant member (3), causes the couplings with the faces of the anterior (10) and posterior elements (11) to redistribute the mechanical strength. This redistribution occurs through communication between the contact rods, anterior (4) or posterior (5), with the displacement restriction region (3a). Thus, a highly efficient component is obtained, where the amount of material supporting deformation energy is maximized; that is, the compliant member redistributes the displacement effect to previously non-stressed regions.

[0055] It is important to note that all internal elements were defined with the same thickness. As a result, homogeneity was maintained between external walls and internal elements. This thickness must be defined as a function of the maximum static strength acting in the form of a critical loading, as well as the fatigue stresses. For the case of DOGs, the possibility of corrosion due to environmental exposure must also be taken into account, and the selection of corrosion-resistant materials or the definition of corrosion over-thickness must be considered.

[0056] Considering that the upper portion of the DOG (1) operates under displacement restrictions, while the lower portion of the DOG (2) is subject to strengths from the Stiffener Helmet, there is a combination with four possible displacement directions for the lower portion of the DOG. Obviously, the combination of two or more directions of action of these strengths is possible. By way of illustration, only the four alternatives illustrated in FIGS. 7 and 8 will be discussed here.

[0057] Thus, considering a strength acting in the vertical direction and starting from the lower portion (2) to the upper portion (1), there is locking of the compliant system in the curvature region (6a) and at the end of the posterior internal rod (6b). As this movement is the opposite of that expected for the DOG under operating conditions, it is defined that these locks occur by so-called reverse movements. When considering the same strength, but now in the opposite direction, that is, from the upper portion (1) to the lower portion (2), there is an upper internal locking (7a) at the free end of the compliant member (3), at the same time that there is a posterior internal locking (7b). As this direction of strength is the one normally supported by DOGs, these locks are defined as coming from normal strengths. Considering a longitudinal strength starting from the posterior face (11) towards the anterior face (10), a movement of translation/rotation occurs towards the body of the Bell Mouth. As a result, the compliant system is locked by the internal wall (8a) at the free end of the compliant member (3c), while the anterior internal locking (8b) occurs in the restriction region (3a).

[0058] Now assuming the longitudinal strength in the opposite direction, moving the lower portion of the DOG towards the opposite direction of the Bell Mouth, the locking of the compliant system occurs by closing the line of discontinuity at the end of the curvature of the DOG (9a) and with a repetition of the posterior internal locking movement (9b).

[0059] Depending on the magnitude and direction of action of the strengths, one or more locking regions may occur. During an operational loading, therefore, locking regions can migrate from one region to another along the structure of the compliant member (3).

[0060] Thus, the deformation mechanism of this invention allows the support of all types of strengths required in couplings of this type and similar, avoiding high stress concentrations that occur in conventional solutions. This versatility is precisely what makes the compliant DOG so efficient in redistributing strengths to non-stressed regions and providing greater structural flexibility.

[0061] Structurally, the present invention proposes a structural mechanism formed by individually more flexible parts than a massive DOG. But when under loading, these parts deform in a pre-specified way, transferring part of a loading that would be excessive in a given region to another less loaded region. This occurs by the action of the external load itself, using the component deformation, without any external power supply or interference. It is this pattern of deformation that relieves stresses where they are greatest and at the same time provides the flexibility (compliance) that best divides coupling loads between the various DOGs.

[0062] Thus, essentially, the present invention relies on a structure with the same external geometry of a generic hook, but with a topology (internal structuring) that allows greater deformation of the part with load transfer to other less stressed regions.

[0063] The movement conformation strategy to maximize the displacement on the support face and minimize the stresses acting in the critical regions (curvature) of the DOG makes this type of component applicable to any operations/structures that make use of acting components in a gripping position (hook type) coupling different components in specific positions/configurations. Among the possible fields of application, there can be mentioned: [0064] 1Extremities of structures for lifting loads for mining; [0065] 2Lifting systems used in the airport environment and in the civil construction sector; [0066] 3Anchoring spikes for structures subject to wind loads; [0067] 4Any and all systems that require high mechanical strength to support weight/load, while at the same time presenting high flexibility to conform to considerable displacement and/or force strengths.

[0068] Due to the ability to conform to displacements of considerable magnitude with material distribution absorbing a greater amount of deformation energy, the concept of compliant DOG can be extended to applications that combine the needs of high mechanical strength with high flexibility to meet cyclic prescribed displacement requirements.

[0069] Accordingly, those skilled in the art will value the knowledge presented herein and will be able to reproduce the invention in the presented embodiments in other variants, encompassed in the scope of the attached claims.