Systems, devices and methods for monitoring support platform structural conditions
Systems, devices and methods enable generation and monitoring of support platform structural conditions in a manner that overcomes drawbacks associated with conventional approaches (e.g., load cells) for generating and monitoring similar operating condition information. In preferred embodiments, such systems, devices and methods utilize fiber optic strain gauges (i.e., fiber optic sensors) in place of (e.g., retrofit/data replacement) or in combination with conventional load cells. The fiber optic sensors are strategically placed at a plurality of locations on one or more support bodies of a support platform. In preferred embodiments, the fiber optic strain gauges are placed in positions within a hull and/or one or more pontoons of an offshore platform. Such positions are selected whereby resulting operating condition data generated by the fiber optic strain gauges suitably replaces data received by conventionally constructed and located load cells of an offshore platform (e.g., a TLP).
1 . A method of instrumenting an offshore platform to enable monitoring of structural loadings required for securing the offshore platform to a seabed, comprising:
one of obtaining and determining strain gauge placement information for one or more strain gauges being attached to a structural member of a structural body of the offshore platform, wherein the strain gauge placement information is a function of strain field information for loadings exerted on the structural body by a plurality of elongated seabed anchoring bodies each attached to the structural body at an exterior portion thereof and to the seabed for securing the offshore platform to the seabed, wherein the structural body includes an interior space, and wherein at least a portion of the structural member is located within the interior space; and
attaching one or more strain gauges directly to a portion of the structural member located within the interior space of the structural body in accordance with the strain gauge placement information.
2 . The method of claim 1 wherein the structural member spans at least partially across the interior space of the structural body.
3 . The method of claim 2 wherein:
the structural body includes a tip tank; and
the structural member is located within the tip tank.
4 . The method of claim 1 wherein the placement information includes a location of the structural member at which each of the one or more strain gauges is to be attached thereto and an angular orientation of a sensing axis thereof relative to an angular orientation reference axis.
5 . The method of claim 4 wherein the placement information specifies a surface of the structural member to which each of the one or more strain gauges are attached.
6 . The method of claim 1 wherein:
the strain field information identifies a plurality of strain field regions each exhibiting strain in a respective generalized direction relative to a vertical reference axis laying within a surface of the structural member; and
the placement information specifies a respective one of the strain field regions within which each of the one or more strain gauges is to be attached to the respective surface with the sensing axis thereof at least approximately aligned with the respective generalized strain direction of the sensing axis.
7 . The method of claim 6 wherein the structural member spans at least partially across the interior space of the structural body.
8 . The method of claim 7 wherein:
the structural body includes a tip tank; and
the structural member is located within the tip tank.
9 . The method of claim 1 wherein:
the placement information specifies a surface of the structural member to which at least a portion of the one or more strain gauges are attached;
a vertical reference axis lies within the surface;
a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis;
a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and
a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
10 . An offshore platform, comprising:
a structural body having exerted thereon forces generated by securing the offshore platform to the seabed by a plurality of elongated seabed anchoring bodies each attached to the structural body at an exterior portion thereof and to the seabed, wherein the structural body includes an interior space;
a structural member located at least partially within the interior space of and fixedly attached to the structural body; and
one or more strain gauges, wherein each of the one or more strain gauges is attached directly to the structural member on a surface thereof located within the interior space of the structural body, wherein each of the one or more strain gauges is attached in accordance with strain gauge placement information derived from strain field information within the structural member, and wherein the strain field information is a function of loadings corresponding to said forces generated by securing the offshore platform to the seabed.
11 . The offshore platform of claim 10 wherein the structural member:
spans across the interior space of the structural body; and
is attached at opposing end portions thereof to the structural body.
12 . The offshore platform of claim 11 wherein:
the structural body includes a tip tank; and
the structural member is located within the tip tank.
13 . The offshore platform of claim 10 wherein each of the one or more strain gauges is attached to a surface of the structural member within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis.
14 . The offshore platform of claim 13 wherein:
a vertical reference axis lies within the surface;
a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis;
a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and
a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
15 . The offshore platform of claim 10 wherein:
the placement information specifies a surface of the structural member to which the one or more strain gauges are attached;
a vertical reference axis lies within the surface;
a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis;
a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and
a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
16 . The offshore platform of claim 10 wherein the placement information includes a location of the structural member at which each of the one or more strain gauges is to be attached thereto and an angular orientation of a sensing axis thereof relative to an angular orientation reference axis.
17 . The offshore platform of claim 16 wherein the structural member:
spans across the interior space of the structural body; and
is attached at opposing end portions thereof to the structural body.
18 . The offshore platform of claim 17 wherein:
the placement information specifies a surface of the structural member to which the one or more strain gauges are attached;
a vertical reference axis lies within the surface;
a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis;
a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and
a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
19 . The offshore platform of claim 18 wherein each of the strain gauges is attached to the surface within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis.
20 . The offshore platform of claim 10 wherein:
the placement information specifies a surface of the structural member to which at least a portion of the one or more strain gauges are attached;
each of the one or more strain gauges is attached to the surface within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis;
a vertical reference axis lies within the surface;
a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis;
a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and
a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.