Intelligent material based buoyant platform and its structural self-recovery method

Abstract

The application discloses a floating pontoon type platform based on intelligent materials and a structure self-recovery method thereof, the platform adopts an isosceles triangular floating pontoon type structure, and the method comprises the following steps: S1, collecting platform structure real-time response data; S2, constructing a response driving type posture offset function; S3, obtaining an excitation temperature rise condition required by a shape memory alloy execution unit for executing recovery changes; S4, calculating platform structure offset recovery stress; and S5, recovering the platform structure and detecting the recovered platform structure in real time. Through the setting of the shape memory alloy execution unit and the functional gradient material, the response amount corresponding to the floating pontoon type platform is taken as input data, a closed-loop control method from platform structure offset risk identification to self-recovery is constructed, offset data can be obtained in real time, offset structure self-recovery can be performed, periodical manual inspection is not needed, the platform structure offset trend can be monitored in real time, and the problems of lacking automatic monitoring and dynamic adjustment mechanisms are effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of offshore floating wind turbines and relates to a floating cylinder type platform based on intelligent materials and a structure self-recovery method thereof. BACKGROUND

[0002] A floating wind turbine is a kind of offshore power generation equipment adopting a floating structure to support a wind turbine and is suitable for deep water sea area development. Most of the floating wind turbines are implemented by a floating cylinder type semi-submersible platform combined with an anchor chain mooring system to realize a floating foundation. With the rapid development of offshore wind power, the resources available for exploitation in near sea areas are gradually saturated, so it is an inevitable trend for the offshore wind power industry to develop into deep sea. The floating wind turbine breaks through the limitation of the traditional fixed foundation and is more suitable for deep water sea areas, so it is mainly deployed in deep sea areas to obtain high-density wind energy resources.

[0003] However, the floating wind turbine is subjected to the coupling effect of wind, wave and flow for a long time during operation. Stress concentration and fatigue accumulation occur at the connection of the transition area of the connection structure of the floating cylinder type floating platform, which easily leads to the risk of fatigue damage of the floating platform structure and even the displacement of the structure connection point of the floating platform structure. At present, the conventional maintenance and repair method of the floating cylinder type floating platform is to optimize the floating platform structure and the mooring system. However, the optimization of the structure leads to the increase of the self-weight cost of the platform, and stress concentration and fatigue accumulation are still likely to occur in the transition area of the floating cylinder, the connecting beam and the tower column. Although the optimization of the mooring system can effectively position the platform under the rated sea conditions, it is still likely to cause the breakage of the anchor chain or the fatigue damage of the mooring cable when facing complex weather or severe sea conditions. Moreover, the existing traditional maintenance method mainly relies on regular manual inspection and cannot realize real-time sensing of the displacement trend, so it lacks automatic monitoring and dynamic adjustment mechanism. Therefore, the conventional maintenance method has high maintenance cost and needs professional team operation. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the application provides a floating cylinder type platform based on intelligent materials and a structure self-recovery method thereof. The detector is used to collect real-time response data of the floating cylinder type platform structure, and the coupling mechanism of the passive buffering of the functionally graded material transition layer and the active recovery of the shape memory alloy execution unit is used to realize the rapid self-recovery and long-life operation ability of the floating cylinder type platform under cyclic disturbance.

[0005] The technical scheme adopted by the application is as follows.

[0006] A structure self-recovery method of a floating cylinder type platform based on intelligent materials, comprising the following steps:

[0007] S1, collecting real-time response data of the floating cylinder type platform structure by using a detector;

[0008] The pontoon type platform comprises a pontoon group, the pontoon group is composed of three pontoons, is distributed in the shape of an isosceles triangle, a tower column is arranged at the center, a plurality of connecting members are connected between the pontoons and between the tower column and each pontoon, detectors are arranged on the outer walls of the pontoons and the bottom of the tower column, a functional gradient material transition layer is arranged at the connection between the pontoon, the tower column and the connecting member, a shape memory alloy execution unit is arranged on each connecting member between the tower column and the pontoon, the shape memory alloy execution unit is connected with the pontoon and the tower column at two ends respectively, a heating element is covered on the surface of the shape memory alloy execution unit, and the heating element is connected with a control circuit.

[0009] S2, based on real-time response data, a response-driven attitude offset function is constructed for identifying the offset attitude of the pontoon type platform;

[0010] S3, based on the offset attitude of the pontoon type platform, the excitation temperature rise data required for the shape memory alloy execution unit to execute recovery changes are calculated;

[0011] S4, pontoon type platform structure offset recovery stress calculation;

[0012] S5, the control circuit controls the shape memory alloy execution unit to act through the heating element, recovers the pontoon type platform structure, and detects the recovered pontoon type platform structure in real time, so as to realize control and feedback closed loop.

[0013] Further, in S1, the real-time response data of the pontoon type platform structure includes the roll angle of the attitude inclination angle , the longitudinal swing angle , the displacement difference between the pontoons , the stress gradient of the connecting beam , the bending moment at the root of the tower column , and the current strain of each control unit node .

[0014] Further, in S2, the response-driven attitude offset function is:

[0015]

[0016] wherein, is the synthetic attitude offset degree of the pontoon type platform, indicating the instability degree of the overall structure; is a pontoon type platform state identification function;

[0017] The form of the is:

[0018]

[0019] wherein, The coefficients fitted for the adjustment period of the buoyant platform.

[0020] Further, in the S3, the calculation formula of the excitation temperature rise is:

[0021]

[0022] Wherein, The excitation temperature rise required for performing the recovery behavior; The density of the functionally graded material layer structure, in , determines the heat capacity and heat conduction path; The length of the connecting beam, in , affects the deformation interval and heat diffusion time; The elastic modulus of the shape memory alloy execution unit, in , determines the response strength; The synthetic attitude offset degree of the buoyant platform, output by the state identification function of the buoyant platform, The structure-adaptive thermal excitation demand function; based on the local structure characteristics of the buoyant platform, the material thermal response demand, and the current offset degree, output the accurate required temperature rise;

[0023] The The representative form is:

[0024]

[0025] Wherein The design constant, taking a value of 1.0-2.5;

[0026] The excitation power formula is:

[0027]

[0028] Wherein, The specific heat capacity of the material, in The mass of the target structure unit, in The excitation execution period, in The theoretical heating power required by the excitation system, in .

[0029] Further, in the S4, the structure offset recovery stress of the buoyant platform is calculated, and a maintenance response priority matrix is established first, and the formula is as follows:

[0030]

[0031] Wherein, The first layer structure, the first The incentive priority coefficient of the node is 0-1; The whole structure distributed recovery strategy matrix;

[0032] The recovery incentive stress of each node is calculated, and the formula is:

[0033]

[0034] Wherein, The target recovery stress of the first node , The weight value of the node extracted by the matrix ; The elastic modulus of the material used by the node ; The target safety posture angle of the pontoon type platform; The current strain value of the first node ; The synthesized posture offset degree of the pontoon type platform.

[0035] Further, the target safety posture angle of the pontoon type platform in the S4 The range is between 1° and 2°.

[0036] Further, in the S5, the pontoon type platform structure recovery index is calculated by the posture measurement result of the detector measurement unit arranged on the platform after the thermal excitation ends, and the calculation formula is as follows:

[0037]

[0038] Wherein, The displacement difference between the pontoons after the pontoon type platform structure recovery, The tower column root bending moment after the pontoon type platform structure recovery, The connecting beam stress gradient after the pontoon type platform structure recovery, The pontoon type platform structure recovery index, The safety threshold value, When, The safety threshold value is used for the next round of recovery control in the Iteration, The detection times, the alarm is sent after the over-limit times; When, the closed loop ends and records the history For subsequent self-learning.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] ​1. The application sets shape memory alloy execution units and functional gradient materials in the key transition area of the pontoon platform, when stress concentration and fatigue accumulation occur in the transition area of the pontoon platform, the two are matched, the detector detects the corresponding response amount of the pontoon platform as input data, and a closed-loop control method from pontoon platform structure offset risk identification to self-recovery is constructed, which can detect and calculate the offset data of the pontoon platform in time, and perform self-recovery of the offset structure, without the need for regular manual inspection, and can detect the structure offset trend of the pontoon platform in real time, effectively solving the problem of lack of automatic monitoring and dynamic adjustment mechanism.

[0041] 2. Compared with the traditional thickening and high-strength material redundancy method, the application sets shape memory alloy execution units and functional gradient materials in the key transition area of the pontoon platform, which achieves the purpose of self-recovery of the pontoon platform structure offset by matching the two, effectively reduces the structure weight and reduces the maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The figure is a structural schematic diagram of the application.

[0043] Figure 2 The figure is a bottom schematic diagram of the application.

[0044] Figure 3 The figure is a cross-sectional view of the pontoon and pontoon connection of the application.

[0045] Figure 4 The figure is a cross-sectional view of the tower column and pontoon connection of the application.

[0046] Figure 5 The figure is a flowchart of the application.

[0047] Figure 6 The figure is a node response comparison curve diagram of the application.

[0048] In the figure: 1, pontoon; 2, horizontal connecting beam; 3, tower column; 4, detector; 5, inclined connecting beam; 6, shape memory alloy execution unit; 7, functional gradient material transition layer. DETAILED DESCRIPTION

[0049] The technical solutions of the application are described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0050] As shown in the figure, the embodiment provides a pontoon platform structure offset risk identification to self-recovery closed-loop control method. Figures 1 to 4

[0051] As shown in the figure, the embodiment provides a pontoon platform structure offset risk identification to self-recovery closed-loop control method. Figures 1-5 ​As shown, a structure self-recovery method applied to the smart material-based buoyant platform, comprising the following steps:

[0052] S1, collecting real-time response data of the buoyant platform structure by using a detector;

[0053] The buoyant platform comprises a buoy group, the buoy group is composed of three buoys 1, is distributed in an isosceles triangular shape, and a tower column 3 is arranged at the center thereof, the buoys 1 are connected by a plurality of connecting members, and the tower column 3 is connected with each of the buoys 1 by a plurality of connecting members; a detector 4 is arranged on the outer wall of each of the buoys 1 and the bottom of the tower column 3; a functional gradient material transition layer 7 is arranged at the connection between each of the buoys 1 and the tower column 3; a shape memory alloy execution unit 6 is arranged on the connecting beam between each of the buoys 1 and the tower column 3, and the two ends of the shape memory alloy execution unit 6 are connected with the buoys 1 and the tower column 3, respectively; a heating element is arranged on the surface of the shape memory alloy execution unit 6, and the heating element is connected with a control circuit.

[0054] Specifically, the three buoys 1 are symmetrically arranged in an equilateral triangle, and the diameters of the buoys 1 are greater than that of the tower column 3, so as to provide buoyancy and stability; the tower column 3 is vertically arranged at the center of the triangle, and is used for bearing a wind turbine tower and a unit; the elastic modulus of the functional gradient material transition layer 7 gradually changes in the thickness direction, so as to form an elastic modulus gradient region in the thickness direction, thereby reducing the stiffness mutation between the connecting beam end and the buoy 1 and between the connecting beam end and the tower column 3, and weakening stress concentration; the shape memory alloy execution unit 6 is in the form of a patch component, the heating element is controlled by the control circuit to be heated and excited, the shape memory alloy execution unit 6 is caused to change phase under the thermal excitation, and is contracted in the axial direction, so as to form a recovery tension through the rigid connection with the buoy and the tower column, the additional displacement and bending moment caused by the attitude deviation are offset, the attitude of the buoyant platform is restored to a safe range, and the recovery and attitude correction of the structure deviation of the buoyant platform are realized.

[0055] Preferably, the connecting member is a connecting beam, which comprises a horizontal connecting beam 2 for horizontal connection and an inclined connecting beam 5 for inclined connection.

[0056] Specifically, there are fifteen connecting beams in total, including twelve horizontal connecting beams 2 and three inclined connecting beams 5; six horizontal connecting beams 2 connect the buoys 1, the upper part of each of the buoys 1 and the tower column 3, and six horizontal connecting beams 2 connect the buoys 1, the lower part of each of the buoys 1 and the tower column 3; three inclined connecting beams 5 connect the lower part of the tower column 3 and the upper part of each of the buoys 1, so as to form an upper and lower symmetrical frame structure, that is, the horizontal connecting beam 2 and the inclined connecting beam 5 reliably connect the buoys 1 and the tower column 3, form an overall stiffness skeleton, and can effectively improve the stability between the buoys 1 and the tower column 3.

[0057] Preferably, the detector includes a ship-grade MEMS-IMU, a short-stroke LVDT, an FBG optical fiber strain gauge, a fiber Bragg grating group, and a K-type thermocouple; the ship-grade MEMS-IMU is fixed to the bottom of the tower column 3; the short-stroke LVDT is connected between the end of the connecting beam and the buoy 1, and the sensor axis is consistent with the main relative displacement direction of the two; that is, the short-stroke LVDT is arranged between the buoy 1 and the connecting beam 2, and between the buoy 1 and the tower column 3; the control circuit reads the relative displacement of each measuring point at a preset sampling period , and processes the relative displacement of different measuring points under the same working condition to obtain the displacement difference between the buoys and between the buoys and the tower column , the as one of the inputs of the response-driven attitude offset function , for reflecting the influence of the coupling between the buoys and the eccentric support on the overall attitude; the short-stroke LVDT is connected between the end of the connecting beam and the buoy 1, and the sensor axis is consistent with the main relative displacement direction of the two; The optical fiber strain gauge is arranged obliquely at the connection between the connecting beam 5 and the tower column 3; the fiber Bragg grating group is arranged in a circumferential equiangular ring at the bottom of the tower column 3; and the K-type thermocouple is arranged at the side of the end of the shape memory alloy execution unit 6.

[0058] Specifically, the ship-grade MEMS-IMU has a range of ±30° and a resolution of ≤0.001°, and is used for calculating the overall attitude and providing input for the criterion; the short-stroke LVDT has a range of ±50 mm and a linearity of ≤0.25% FS; the FBG optical fiber strain gauge is provided with a temperature compensation grid, and a resistance strain gauge is additionally provided if necessary; the K-type thermocouple is arranged at the side of the end of the shape memory alloy execution unit 6,

[0059] Specifically, the ship-grade MEMS-IMU, the short-stroke LVDT, and the FBG optical fiber strain gauge are used for real-time monitoring of the strain and displacement of the buoy 1; the fiber Bragg grating group is used for monitoring the bending moment of the tower column 3 and the overall attitude response; and the detection data of the above detectors jointly constitute a disturbance input vector, which provides data support for the subsequent control method.

[0060] Specifically, the real-time response data of the buoy-type platform structure collected by the detector includes the roll angle , the pitch angle , the displacement difference between the buoys , the stress gradient of the connecting beam , the bending moment at the root of the tower column , and the current strain of each control unit node .

[0061] S2, based on the real-time response data, a response-driven attitude offset function is constructed for identifying the offset attitude of the buoy-type platform;

[0062] Specifically, the response-driven attitude deflection function is:

[0063]

[0064] wherein, is the synthetic attitude deflection degree of the pontoon platform, indicating the instability degree of the overall structure; is the pontoon platform state identification function; in the detection process, the index that destroys the symmetry of the pontoon platform structure is input, and the comprehensive deflection evaluation value is output; so as to reflect the unique response behavior of the pontoon platform, such as the coupling effect between the floating bodies, the support eccentricity and the change of lateral stiffness of the pontoon platform;

[0065] The form of the response-driven attitude deflection function is:

[0066]

[0067] wherein, is the coefficient obtained by fitting during the debugging period of the pontoon platform, that is, the simulation test data obtained based on the platform scale test, the function is bound to the three-pontoon platform structure, the input source is the structural response of the pontoon platform, not the sailing state or inertial information, and cannot be migrated to the system dominated by the structural response of the non-pontoon platform;

[0068] S3, based on the deflection attitude of the pontoon platform, obtaining the excitation temperature rise condition required for the material to perform recovery change;

[0069] Specifically, in the S3, the calculation formula of the excitation temperature rise is:

[0070]

[0071] wherein, is the excitation temperature rise required for performing the recovery behavior; is the density of the functionally gradient material layer structure (ρf), which determines the heat capacity and heat conduction path; is the length of the connecting beam (Lc), which affects the deformation interval and heat diffusion time; is the elastic modulus of the shape memory alloy execution unit (Ef), which determines the response strength; is the overall deflection degree of the pontoon platform, which is output by the pontoon platform state identification function, is the structure-adaptive thermal excitation demand function; based on the local structural characteristics of the pontoon platform, the material thermal response demand and the current deflection degree, the accurate required temperature rise is output; The form of the structure-adaptive thermal excitation demand function is:

[0072] The form of the structure-adaptive thermal excitation demand function is: ​​​​

[0073]

[0074] wherein is a design constant, taking value in the interval [1.0, 2.5] for better control stability; this function is only valid for structures with thermal excitation response mechanism, and cannot be directly applied to rigid buoy type platforms or non-temperature control structure systems;

[0075] The required excitation power of the system is calculated as:

[0076]

[0077] wherein, is the specific heat capacity of the material, with unit of is the mass of the target structure unit, with unit of is the excitation execution period, with unit of ; is the theoretical heating power required by the excitation system, with unit of , which is determined based on the parameters of the shape memory alloy execution unit and the thermal input efficiency; the control circuit calculates the current adjustable power in real time during operation , wherein is the safety redundancy coefficient, , it is determined that the triggering condition is met, thereby executing heating driving, if , it continues to maintain the monitoring state;

[0078] The current adjustable power is determined by the real-time electrical parameters of the DC bus supplying power to the shape memory alloy execution unit, through the voltage and current sensors arranged on the DC bus supplying power to the shape memory alloy execution unit, the control circuit periodically collects the bus voltage and the current bus total current in the running process, and combines the pre-stored rated current allowed to pass through the bus and the safety reduction coefficient , which is calculated in real time, and the calculation formula is as follows:

[0079] wherein, is the current bus voltage, is the current bus total current, is determined by the rated parameters of the power module, is used to reserve power redundancy and avoid bus overload, and the value is 0-1;

[0080] The current adjustable power required in step S3 can be obtained accordingly, or directly read the current available power information provided by the power module to obtain; and compared with the target temperature rise Theoretical heating power obtained from calculation Compare, when satisfied

[0081] Only when the control circuit sends a heating command to the corresponding heating element will it do so; otherwise, it will only maintain attitude monitoring without triggering thermal excitation.

[0082] S4. Calculation of offset recovery stress of pontoon platform structure;

[0083] Specifically, in the calculation of offset recovery stress of the pontoon platform structure in S4, the maintenance response priority matrix is ​​first established, as shown in the following formula:

[0084]

[0085] in, For the first Layer structure The incentive priority coefficient of each node ranges from 0 to 1, with higher values ​​indicating higher priority. The distributed recovery strategy matrix for the entire structure is generated based on the offset structural position, material type, and historical fatigue value. The control circuit can adjust the matrix through hierarchical scheduling, strain over-limit marking, and thermal protection rotation mechanism.

[0086] The formula for calculating the restoring excitation stress at each node is:

[0087]

[0088] in, For the first The target recovery stress of each node ( ), From the matrix The extracted weight value of this node; The elastic modulus of the material used in this node ( When the node is a shape memory alloy execution unit segment, take When the section is a regular section, the equivalent modulus at that location is taken; The safe attitude angle for the pontoon platform target is between 1° and 2°. For the first Current strain value at the node; This represents the current offset of the pontoon platform.

[0089] S5. The control circuit controls the shape memory alloy actuator to change through the heating element, restores the float platform structure, and detects the restored float platform structure in real time, thus realizing a control and feedback closed loop.

[0090] After each round of thermal excitation and a preset stabilization time window, the detector will again collect platform structure response data to obtain the displacement difference between the floats after the platform structure has recovered. Bending moment at the base of the tower column and the stress gradient of the connecting beam And substitute it into the floating platform status recognition function described in step S2. The state indicators of the pontoon platform structure after restoration were calculated, and the formula is as follows:

[0091]

[0092] in, As a safety threshold, when At that time, ,according to Recovery control in the next iteration The number of tests, i.e., when the number of tests... If the number of attempts does not exceed 3, return to steps S2-S4 to recalculate the temperature and perform thermal excitation again. Exceeding Or after multiple iterations, it is still the same. When this happens, an alarm will be issued to notify manual intervention; when When the attitude of the pontoon platform is determined to have returned to a safe range, the closed loop ends and the current response priority matrix is ​​recorded. The relevant recovery process data is used for self-learning and parameter optimization under subsequent working conditions; this calculation method is consistent with the attitude offset synthesis method in step S2.

[0093] Specifically, when the control circuit meets the requirements... Under the conditions, according to the recovery stress and priority coefficient of each node calculated in step S4, a heating command is sent to the corresponding heating element, so that the heating element covering the outer surface of the shape memory alloy actuator is energized and heated. Under thermal excitation, the shape memory alloy actuator undergoes shape memory phase transformation and generates axial contraction. Through the rigid connection between the two ends and the nodes of the float shell, the end of the connecting beam or the root of the tower column, the contraction deformation is converted into a recovery tensile force on the node, thereby offsetting the additional displacement and bending moment generated by the offset, and pushing the attitude of the float platform to recover to the target safe range.

[0094] That is, the detector collects multi-point measurement data from the pontoon, connecting beam, and base of the tower column, and then... Module calculates attitude angles By using a threshold Make a judgment after comparison: if Then enter The module calculates the execution amount required by the shape memory alloy execution unit. And through the matrix distribution to the specific shape memory alloy execution unit, the structure recovery is completed by the shape memory alloy execution unit; then continue to collect the new attitude angle , judge whether to recover to the safe range, if not meet the requirements, through the dashed line feedback path back to module re-identification; iteration is provided in the process, if the iteration times , continue to cycle identification and judgment, if the iteration times exceed the maximum value , enter the alarm state.

[0095] As Figure 6 shown, the horizontal axis is the attitude angle (unit: °), the vertical axis is the residual displacement / equivalent stress (illustrative value); the dashed curve represents the traditional structure, the solid curve represents the scheme of the present application, and the shaded area represents the safe attitude angle range 1°-2°. The curve reflects the response state of the buoy-type platform after the loading-unloading cycle under the action of external disturbance.

[0096] In the traditional structure (dashed curve), due to the serious stress concentration at the node, a large residual displacement occurs after loading and unloading, and the curve is poorly closed, which means that the cyclic response is difficult to recover to the initial zero position.

[0097] In the solid curve shown, the functional gradient material transition layer is introduced at the connection between the buoy, the connecting beam and the tower column to buffer the stress and stiffness, and the shape memory alloy execution unit is set to realize active recovery. The loading to unloading response curve of the structure is close to closed, and the residual displacement is significantly reduced.

[0098] The curve comparison shows that: within the same attitude angle range, the node design of the present application can effectively reduce the residual response, so that the attitude of the buoy-type platform can be kept within the safe range of 1°-2°, which is obviously better than the traditional scheme.

[0099] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

[0100] Finally, it should be pointed out that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A structural self-healing method for a pontoon platform based on smart materials, characterized in that: Includes the following steps: S1. Use detectors to collect real-time response data of the pontoon platform structure; The floating platform includes a floating assembly consisting of three floating pontoons (1) arranged in an isosceles triangle shape, with a tower (3) at its center. The floating pontoons (1) are connected to each other and the tower (3) is connected to each floating pontoon (1) by several connectors. Detectors (4) are provided on the outer wall of the floating pontoons (1) and at the bottom of the tower (3). Functionally graded material transition layers (7) are provided at the connection between the floating pontoons (1), the tower (3) and the connectors. Shape memory alloy actuators (6) are provided on the connectors between the tower (3) and the floating pontoons (1). The two ends of the shape memory alloy actuators (6) are connected to the floating pontoons (1) and the tower (3) respectively. Heating elements are covered on the surface of the shape memory alloy actuators (6), and the heating elements are connected to the control circuit. The connectors are connecting beams, including a horizontal connecting beam (2) for horizontal connection and an oblique connecting beam (5) for inclined connection. S2. Based on real-time response data, construct a response-driven attitude offset function to identify the offset attitude of the pontoon platform; S3. Calculate the excitation temperature rise data required for the shape memory alloy actuator to recover from the change in attitude based on the offset attitude of the float-type platform; S4. Calculation of offset recovery stress of pontoon platform structure; S5. The control circuit controls the shape memory alloy actuator through the heating element to restore the float platform structure and detects the restored float platform structure in real time, thus realizing a control and feedback closed loop.

2. The structural self-restoring method according to claim 1, characterized in that: In step S1, the real-time response data of the pontoon platform structure includes the roll angle of its attitude tilt angle. Longitudinal rocking angle Displacement difference between pontoons Stress gradient of connecting beams Bending moment at the base of the tower column Current strain of each control unit node .

3. The structural self-restoring method according to claim 2, characterized in that: In S2, the response-driven attitude offset function is: ； in, The composite attitude deviation of the pontoon platform; This is a function for identifying the status of a pontoon platform. The The form is: ； in, These are the coefficients obtained from fitting during the commissioning period of the pontoon platform.

4. The structural self-restoring method according to claim 3, characterized in that: In S3, the formula for calculating the excitation temperature rise is: ； in, The necessary incentive temperature rise to perform the recovery behavior; The density of functionally graded material layer structures; This refers to the length of the connecting beam; The elastic modulus of the shape memory alloy actuator; The composite attitude offset of the float-type platform is output from the response-driven attitude offset function of the previous step. For structurally adaptable thermal excitation demand function; The The representative form is: ； in Design constant; The formula for excitation power is: ； in, Specific heat capacity of the material; The target structural unit mass; To incentivize the execution cycle; The theoretical heating power required to excite the system.

5. The structural self-restoring method according to claim 1, characterized in that: In the calculation of the offset recovery stress of the floating platform structure in S4, the maintenance response priority matrix is ​​first established, as shown in the following formula: ； in, For the first Layer structure The incentive priority coefficient for each node; This is the distributed recovery strategy matrix for the entire structure; The formula for calculating the restoring excitation stress at each node is: ； in, For the first The target recovery stress of each node From the matrix The extracted weight value of this node; The elastic modulus of the material used in this node; The safe attitude angle for the floating platform target; For the first Current strain value at the node; This represents the composite attitude offset of the pontoon platform.

6. The structural self-restoring method according to claim 5, characterized in that: The safe attitude angle of the floating platform target in S4 The range is between 1° and 2°.

7. The structural self-restoring method according to claim 5, characterized in that: In step S5, the structural recovery index of the float-type platform is calculated from the attitude measurement results of the detector measurement unit arranged on the platform after the thermal excitation ends. The calculation formula is as follows: ； in, For the displacement difference between the pontoons after the restoration of the pontoon platform structure, The bending moment at the base of the tower column after the restoration of the floating platform structure. The stress gradient of the connecting beams after the restoration of the pontoon platform structure. For the structural restoration indicators of the pontoon platform, As a safety threshold, At that time, according to Recovery control in the next iteration This is the number of times the test can be performed; an alarm will be issued if the limit is exceeded. At that time, the closed loop ends and history is recorded. For subsequent self-learning.

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