Tension control device for tensile elements

A tensile system for attachment between a floating structure having relative movement with respect to a stationary body, comprising:

• at least one tensile element attached to the stationary body;
• and
• at least one first collapsible energy cell coupled between the tensile element and the floating structure, the first collapsible energy cell comprising a first buckling elastomer spring, the first collapsible energy cell having a normal state wherein the first buckling elastomer spring is unbuckled and a collapsed state wherein the first buckling elastomer spring buckles through a range of deflections, the first collapsible energy cell further comprising a buckling restraint member which engages the first buckling elastomer spring in the collapsed state so as to augment the load bearing capacity of the first buckling elastomer spring through the range of deflections;
• wherein the first buckling elastomer spring buckles when a compressive force induced in the first buckling elastomer spring by the relative movement between the floating structure and the stationary body exceeds a critical force.

A method of limiting tension in a tensile element attached between a first body and a second body, comprising:

• selecting a maximum tension and a range of tension variations for the tensile element;
• predicting a range of displacements between the first body and the second body;
• selecting at least one collapsible energy cell having at least one buckling elastomer spring configured to buckle and deflect non-linearly through the predicted range of displacements and a buckling restraint member which engages the buckling elastomer spring so as to augment the load bearing capacity of the buckling elastomer spring as the buckling elastomer spring buckles;
• attaching the tensile element to the first body;
• and
• coupling the tensile element to the second body through the collapsible energy cell such that relative displacements between the first body and the second body induce buckling of the buckling elastomer spring.

A tensile system for attachment between a floating body and a stationary body, comprising:

• at least one riser extending between the floating body and the stationary body, the riser having an end coupled to the stationary body;
• a support base coupled to the floating body, the support base bracing the riser;
• and
• a first riser tensioner having a first end coupled to the riser and a second end coupled to the support base, the riser tensioner comprising a plurality of collapsible energy cells stacked in series, each collapsible energy cell comprising a first elastomer spring and having a normal state wherein the first buckling elastomer spring is unbuckled and a collapsed state wherein the first buckling elastomer spring buckles through a range of deflections, each collapsible energy cell further comprising a buckling restraint member which engages the first buckling elastomer spring so as to augment the load bearing capacity of the first buckling elastomer spring through the range of deflections;
• wherein movement of the support base relative to the riser induces a compressive force to deflect the first buckling elastomer springs, the first buckling elastomer springs maintaining a tension in the riser substantially constant through the range of deflections.

A tensile system for attachment between a floating body and a stationary body, comprising:

• at least one riser extending between the floating body and the stationary body, the riser having an end coupled to the stationary body;
• a support base coupled to the floating body, the support base bracing the riser;
• and
• a first riser tensioner having a first end coupled to the riser and a second end coupled to the support base, the riser tensioner comprising a plurality of collapsible energy cells stacked in series, the collapsible energy cells comprising buckling elastomer springs configured to buckle through a range of deflections in response to movement of the support base relative to the riser and buckling restraint members engaging the buckling elastomer springs so as to produce a non-decreasing reaction force through the range of deflections;
• wherein movement of the support base relative to the riser induces a compressive force on the buckling elastomer springs which induces buckling of the elastomer springs.