A comprehensive analysis device and monitoring method for stress corrosion of marine structures

Abstract

This invention discloses a comprehensive stress corrosion analysis device and monitoring method for marine structures. The device includes a stress loading device, a multi-channel microresistivity measurement device, and measurement components. The stress loading device can apply different elastic stresses to multiple sets of measurement components. Each set of measurement components includes a measuring element, a reference element, and a stress measuring element, and each set of measurement components has multiple monitoring areas. The multi-channel microresistivity measurement device includes a constant current source, multiple voltage measurement modules, and a relay module. The multi-channel microresistivity measurement device can sequentially acquire the resistance of different measuring elements and reference elements at different times, thereby obtaining the corrosion rate of the measuring elements under different elastic stresses. The comprehensive stress corrosion analysis device for marine structures disclosed in this invention can conveniently obtain the corrosion rate of measuring elements under different elastic stresses, thereby realizing the simulation of the corrosion rate of marine structures under different elastic stresses.

Description

Technical Field

[0001] This invention relates to the field of precast pile manufacturing technology, and in particular to a comprehensive analysis device and monitoring method for stress corrosion of marine structures. Background Technology

[0002] With the continuous improvement of marine resource development and utilization technologies, the load-bearing requirements of marine structures (such as offshore platforms, offshore wind turbines, and offshore oil drilling platforms) are gradually increasing. For large marine structures, the internal stress distribution is complex. Under the combined effect of stress and corrosion, not only is the corrosion rate of metallic materials accelerated in the seawater environment, but it also leads to risks such as crack formation and fracture. Therefore, reliable comprehensive monitoring and assessment of the stress-corrosion state of marine structures is particularly important.

[0003] Currently, the main approach to monitoring stress corrosion on marine structures involves simulating stress loads using bending stress loading devices and obtaining corrosion rates through electrochemical testing techniques. However, traditional stress corrosion monitoring technologies cannot reflect localized corrosion issues under different stress loads, nor can they reflect the impact of stress corrosion cells under different stresses on corrosion development. Furthermore, traditional stress corrosion monitoring technologies also struggle to capture the formation and propagation of surface cracks, making accurate assessment of structural damage risk impossible. Summary of the Invention

[0004] This invention proposes a comprehensive stress corrosion analysis device for marine structures to address the above-mentioned problems.

[0005] The technical means employed in this invention are as follows:

[0006] A comprehensive stress corrosion analysis device for marine structures includes: a stress loading device, a multi-channel micro-resistivity measuring device, and measuring components;

[0007] The stress loading device is provided with multiple sets of measuring components in sequence, and the stress loading device applies different elastic stresses to the multiple sets of measuring components.

[0008] Each set of measurement components includes a measuring element, a reference element, and a stress measuring element. The measuring element and the reference element are arranged side by side in the stress loading device and are subjected to the same elastic stress by the stress loading device. Multiple stress measuring elements are provided on the measuring element and the reference element on the stress loading side to form multiple monitoring areas. The positions of the multiple stress measuring elements on the measuring element and the reference element are corresponding.

[0009] The multi-channel microresistance measurement device includes a constant current source, multiple voltage measurement modules, and a relay module. The constant current source is connected to both ends of the measuring element and the reference element to apply a constant current to the measuring element and the reference element. The multiple voltage measurement modules are connected to the measuring element and the reference element to measure the voltage of each monitoring area. The relay module is disposed between the measuring components and the multi-channel microresistance measurement device to electrically connect or disconnect the measuring element and the reference element from the multi-channel microresistance measurement device in sequence.

[0010] Furthermore, it also includes a zero-resistance galvanometer disposed at one end of each of the measuring elements, and a zero-resistance galvanometer access switch is provided between two adjacent measuring elements.

[0011] Furthermore, wires for electrical connection with the voltage measurement module are welded to the sides of the measuring element and the reference element at positions corresponding to the monitoring area.

[0012] Furthermore, both the stress loading device and the reference element have electrically insulating structures on their surfaces;

[0013] The side of the measuring element opposite to the applied elastic stress is an electro-corrosion surface, and the other parts of the measuring element are provided with an electrically insulating structure.

[0014] Furthermore, the stress loading device includes a support frame, a loading plate, and adjusting bolts;

[0015] The support frame is provided with a T-shaped measuring component receiving slot, and the loading plate is provided in the measuring component receiving slot;

[0016] The support frame is provided with a plurality of adjusting bolts on one side of the bottom of the measuring component receiving groove. One end of the adjusting bolt is connected to the loading plate. The adjusting bolt can drive the loading plate to move toward the measuring component placed in the measuring component receiving groove to apply elastic stress to the measuring component.

[0017] Furthermore, the stress loading device is made of nylon material; the reference element and the measuring element are made of the same material, the surface of the reference element is coated with epoxy resin, and the electrically insulating surface of the measuring element is coated with epoxy resin.

[0018] A monitoring method using the integrated stress corrosion analysis device for marine structures described in this application, characterized by comprising the following steps:

[0019] Step 1: Install multiple sets of measuring components sequentially in the stress loading device, apply different elastic stresses to each set of measuring components through the stress loading device, and place them in the test solution;

[0020] Step 2: At set time intervals T, acquire the local stress value σ of each monitoring area of ​​each measuring element through the stress measuring element. cij and the local stress value σ of each monitoring area of ​​each reference element rij ;

[0021] The measuring element and reference element are sequentially connected to the multi-channel micro-resistance measuring device via a relay module to obtain the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij ;

[0022] Where i represents the number of measuring components and j represents the number of monitoring areas;

[0023] Step 3: Based on the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij Obtain the localized metal corrosion Δh in each monitoring area of ​​each measuring element. ij The calculation formula is:

[0024]

[0025]

[0026] in, The local resistance value of the measuring element is measured in the initial stage. The value of the local resistance of the reference element measured in the initial stage is h. cij This is the initial thickness value of the measuring element;

[0027] Step 4: Based on the obtained localized metal corrosion amount Δh ij Calculate the local corrosion rate CR of the measuring element at intervals T. ij The calculation formula is:

[0028] CR ij =Δh ij / T (3);

[0029] Step 5: Based on the obtained local corrosion rate CR of the measuring element ij and local stress value σ cij Establish the local corrosion rate CR for each monitoring area ij The relationship between the stress and the local stress value σ.

[0030] Furthermore, it also includes the local resistance value R of each monitoring area of ​​each measuring element obtained. cijand the local resistance value R of each monitoring area of ​​each reference element rij Calculate the resistance ratio k of each monitoring area of ​​the measuring element and the reference element. ij The calculation formula is:

[0031] k ij =R cij / R rij (4)

[0032] And based on the resistance ratio k of each monitoring region of the measuring element and the reference element ij Obtain the resistance ratio k ij The curve showing the relationship between resistance and time is based on the resistance ratio k. ij The rate of change of resistivity Δk is obtained from the curve of the relationship between resistivity and time. ij ;

[0033] The obtained resistance ratio change rate Δk ij The rate of change of resistance ratio k s A comparison is made to determine whether the measuring element has a crack. The specific determination process is as follows:

[0034] If Δk ij ≥k s Determine if the measuring element has cracked; if Δk ij <k s If the measurement element is intact, it can be determined that no crack has occurred.

[0035] Furthermore, the set resistance ratio change rate k s The calculation process is as follows:

[0036] Obtain the corrosion rate CR0 of the measuring element under no elastic stress; obtain the corrosion rate CR of the measuring element under applied elastic stress σ. σ ; Calculate the resistance ratio k of the measuring element and the reference element when elastic stress σ is applied. σ The calculation formula is as follows:

[0037]

[0038] k σ Taking the first derivative with respect to time T, we obtain the rate of change of resistivity k under applied elastic stress σ. σ The calculation formula is as follows:

[0039]

[0040] Let ks = 2 ~ 3kσ.

[0041] Furthermore, it also includes the following steps:

[0042] Disconnect all measuring elements and reference elements from the multi-channel micro resistance measuring device by using the relay module, connect the zero resistance ammeter to the measuring element by using the zero resistance ammeter access switch, and connect multiple sets of measuring elements in parallel.

[0043] The thermocouple currents I1 to I2 between each measuring element are obtained sequentially using each zero-resistance galvanometer. i This allows us to obtain information about the corrosion of the measuring element under different elastic stresses.

[0044] Compared with existing technologies, the comprehensive stress corrosion analysis device for marine structures disclosed in this invention has the following advantages: The comprehensive stress corrosion analysis device for marine structures disclosed in this invention, by setting multiple sets of measuring components on the stress loading device and applying different elastic stresses to each set of measuring components, and obtaining the resistance values ​​of each monitoring area of ​​each measuring element and reference element through a multi-channel micro-resistance measuring device, can conveniently obtain the corrosion rate of the measuring elements under different elastic stresses, thereby simulating the corrosion rate of marine structures under different elastic stresses. This allows for the simulation of local corrosion damage in areas subjected to different loads, closely reflecting the actual service conditions of marine structures. Attached Figure Description

[0045] Figure 1 This is an axial view of the stress loading device of the marine structure stress corrosion comprehensive analysis apparatus disclosed in this invention;

[0046] Figure 2 This is an end view of the stress loading device of the marine structure stress corrosion comprehensive analysis apparatus disclosed in this invention;

[0047] Figure 3 This is a schematic diagram showing the connection between the measurement components, the multi-channel micro-electrical unit measurement device, the zero-resistance galvanometer, and the zero-resistance galvanometer access switch in the marine structure stress corrosion comprehensive analysis device disclosed in this invention.

[0048] Figure 4 This is a schematic diagram showing the connection between the measuring element and the voltage measuring module in the marine structure stress corrosion comprehensive analysis device disclosed in this invention.

[0049] In the diagram: 1. Stress loading device; 10. Support frame; 100. Test component receiving slot; 11. Loading plate; 110. Rib; 12. Adjusting bolt; 13. Support roller; 2. Multi-channel micro-resistance measuring device; 20. Constant current source; 21. Voltage measurement module; 22. Relay module; 3. Measuring component; 30. Measuring element; 31. Reference element; 32. Stress measuring element; 33. Monitoring area; 40. Zero resistance galvanometer; 41. Zero resistance galvanometer connection switch. Detailed Implementation

[0050] Example 1

[0051] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the marine structure stress corrosion comprehensive analysis device disclosed in this invention includes: a stress loading device 1, a multi-channel micro-resistance measuring device 2, and a measuring component 3;

[0052] The stress loading device 1 is provided with multiple sets of measuring components 3 in sequence, and the stress loading device 1 applies different elastic stresses to the multiple sets of measuring components 3.

[0053] Each set of measurement components 3 includes a measuring element 30, a reference element 31, and a stress measuring element 32. The measuring element 30 and the reference element 31 are arranged side by side in the stress loading device 1 and are subjected to the same elastic stress by the stress loading device 1. Multiple stress measuring elements 32 are provided on the measuring element 30 and the reference element 31 on the stress loading side to form multiple monitoring areas 33. The positions of the multiple stress measuring elements 32 on the measuring element 30 and the reference element 31 are corresponding.

[0054] The multi-channel microresistance measuring device 2 includes a constant current source 20, multiple voltage measurement modules 21, and a relay module 22. The constant current source 20 is connected to both ends of the measuring element 30 and the reference element 31, and is used to apply a constant current to the measuring element 30 and the reference element 31. The multiple voltage measurement modules 21 are connected to the measuring element 30 and the reference element 31, and are used to measure the voltage of each monitoring area 33 respectively. The relay module 22 is disposed between the measuring component 3 and the multi-channel microresistance measuring device 2, and is used to electrically connect or disconnect the measuring element 30 and the reference element 31 to the multi-channel microresistance measuring device 2 in sequence.

[0055] Specifically, the marine structure stress corrosion comprehensive analysis device disclosed in this invention includes a stress loading device 1, on which multiple sets of measuring components 3 are installed. Figure 1As shown in the figure, in this embodiment, the number of measuring components 3 is 3 groups. The specific number of measuring components can be set according to needs. The stress loading device 1 can apply a force to the measuring components 3, causing the measuring components 3 to undergo elastic deformation and thus generate elastic stress. The elastic stress in each group of measuring components 3 is different, that is, different elastic stresses are applied to multiple groups of measuring components to simulate the load conditions of metal structures under different elastic stresses through the loading device. Each group of measuring components includes a measuring element 30, a reference element 31, and a stress measuring element 32. The measuring element 30 and the reference element 31 are arranged side by side. The same force is applied to one side of the measuring element 30 and the reference element 31 by the loading structure of the stress loading device, causing the measuring element 30 and the reference element 31 to bend and generate elastic stress. Multiple stress measuring elements 32 are uniformly arranged on the side of the measuring element 30 and the reference element 31 on which the force is applied to form multiple monitoring areas 33. In this embodiment, the stress measuring element 32 is a strain gauge. Figure 1As shown, both the measuring element 30 and the reference element 31 are equipped with five strain gauges, forming five monitoring areas. The positions of the strain gauges on the measuring element 30 and the reference element 31 correspond to ensure that the monitoring areas on the measuring element 30 and the reference element 31 are consistent, thereby ensuring the accuracy of the monitoring results. The monitoring component 3 is electrically connected to the multi-channel micro-resistance measuring device 2. The multi-channel micro-resistance measuring device 2 includes a constant current source 20, a voltage measurement module 21, and a relay module 22. The constant current source 20 is connected to the two ends of the measuring element 30 and the reference element 31 through wires to apply a constant current to the measuring element 30 and the reference element 31. In this embodiment, the constant current source 20 can apply a current of 1A to the measuring element 30 and the reference element 31. The voltage measurement module 21 is connected to the measuring element 30 and the reference element 31 to measure the voltage of each monitoring area 33. In this embodiment, the voltage measurement module includes five voltmeters, which are respectively connected to the two ends of the five monitoring areas to measure the voltage of each monitoring area 33. A relay module 22 is disposed between the measuring component 3 and the multi-channel micro-resistance measuring device 2 (constant current source and voltage measurement module). It is used to electrically connect or disconnect the measuring element 30 and the reference element 31 sequentially to the multi-channel micro-resistance measuring device 2 (constant current source and voltage measurement module). In this embodiment, the relay module is a 6-way switch, used to electrically connect or disconnect each measuring element and reference element to the multi-channel micro-resistance measuring device 2, thereby enabling the multi-channel micro-resistance device to obtain the resistance value of each monitoring area of ​​each measuring element and reference element. The marine structure stress corrosion comprehensive analysis device disclosed in this invention, by setting multiple sets of measuring components on the stress loading device and applying different elastic stresses to each set of measuring components, and obtaining the resistance value of each monitoring area of ​​each measuring element and reference element through the multi-channel micro-resistance measuring device, can conveniently obtain the corrosion rate of the measuring elements under different elastic stresses, thereby simulating the corrosion rate of marine structures under different elastic stresses. This allows for the simulation of local corrosion damage in areas subjected to different loads, closely matching the actual service conditions of marine structures.

[0056] Furthermore, it also includes a zero-resistance galvanometer 40 disposed at one end of each of the measuring elements 30, and a zero-resistance galvanometer access switch 41 is provided between two adjacent measuring elements 30.

[0057] Specifically, in this embodiment, a zero-resistance galvanometer 40 is provided at one end of each measuring element 30, and a zero-resistance galvanometer access switch 41 is provided between two adjacent measuring elements 30. The zero-resistance galvanometer access switch can be used to connect or disconnect one end of multiple measuring elements to each other, and at the same time connect or disconnect the zero-resistance galvanometer to the measuring element. When the zero-resistance galvanometer is connected to the measuring element, the current in the corresponding measuring element can be measured. In this embodiment, by setting a zero-resistance galvanometer 40 and a zero-resistance galvanometer access switch 41, the corrosion status of the measuring element under different elastic stresses can be obtained. Specifically, when it is necessary to set a zero-resistance galvanometer 40 and a zero-resistance galvanometer access switch 41 to obtain the corrosion status of the measuring element under different elastic stresses, the electrical connection between all measuring elements and reference elements and the multi-channel micro-resistance measuring device is disconnected through the relay module, and the device is placed in the test solution (corrosion solution). The zero-resistance galvanometer access switch 41 is closed so that the zero-resistance galvanometer 40 is connected to the measuring element. A galvanic cell structure is formed between multiple measuring elements, so the corrosion status of different measuring elements can be obtained according to the reading of each zero-resistance galvanometer, and thus the corrosion status of the measuring element under different stresses can be obtained.

[0058] Furthermore, wires for electrical connection with the voltage measurement module 21 are welded to the sides of the measuring element 30 and the reference element 31 at positions corresponding to the monitoring area 33.

[0059] Specifically, in this embodiment, in order to ensure the accuracy of the measurement results, and at the same time, to ensure that the connection between the wires and the measuring element and the reference element does not affect the simulation test results, wires are welded to the sides of the measuring element and the reference element at positions corresponding to the monitoring area, and the other end of the wires is connected to the terminal of the corresponding voltage measurement module. Wires for electrical connection with the constant current source are welded to both ends of the measuring element and the reference element.

[0060] Furthermore, the surfaces of the stress loading device 1 and the reference element 31 are both electrically insulating structures;

[0061] The side of the measuring element 30 opposite to the side to which the elastic stress is applied is an electro-corrosion surface, and the other parts of the measuring element 30 are provided with an electrically insulating structure.

[0062] Specifically, in this embodiment, the measuring element and the reference element are made of the same material and have the same specifications to ensure that the elastic stress generated within the measuring element and the reference element is consistent. The outer surfaces of both the reference element and the stress loading device are electrically insulating. This ensures that galvanic corrosion will not occur between the reference element and the stress loading device and the measuring element during the simulation experiment, thus guaranteeing the accuracy of the measurement results. The side of the measuring element opposite to the applied elastic stress is the electro-corrosion surface (test surface), while the other parts of the test element are electrically insulating, further ensuring the accuracy of the simulation results.

[0063] Furthermore, the stress loading device 1 includes a support frame 10, a loading plate 11, and an adjusting bolt 12;

[0064] The support frame 10 is provided with a T-shaped measuring component receiving groove 100, and the loading plate 11 is provided in the measuring component receiving groove 100;

[0065] The support frame 10 is provided with a plurality of adjusting bolts 12 on one side of the bottom of the measuring component receiving groove 100. One end of the adjusting bolt 12 is connected to the loading plate 11. The adjusting bolt 12 can drive the loading plate 11 to move toward the measuring component 3 placed in the measuring component receiving groove 100 to apply elastic stress to the measuring component 3.

[0066] Specifically, in this embodiment, the stress loading device 1 includes a support frame 10, a loading plate 11, and an adjusting bolt 12. The support frame 10 is a long strip structure. A T-shaped measuring component receiving groove 100 is provided on one side of the support frame 10. Multiple threaded holes are provided at the bottom of the measuring component receiving groove 100 along the length direction of the receiving groove. The adjusting bolt 12 is installed in the threaded holes. The end of the adjusting bolt 12 placed in the measuring component receiving groove is provided with the loading plate 11. The loading plate 11 is hinged to the adjusting bolt 12. The width of the loading plate 11 is consistent with the width of a set of measuring components. The side of the loading plate 11 facing the measuring components is provided with two protruding ribs 110. The direction of the protruding ribs is consistent with the width direction of the measuring components. When the measuring components are placed in the measuring component receiving groove, both ends of the measuring components (measuring element and reference element) are inserted into the two ends of the T-shaped measuring component receiving groove. Preferably, support rollers 13 are provided inside the two ends of the T-shaped measuring component receiving groove, so that the measuring element and reference element and the stress loading device form a four-point bending structure. The measuring components are subjected to force through the four-point bending structure, causing them to bend and generate elastic stress. Multiple sets of measuring components are arranged sequentially along the length of the measuring component receiving groove, and different elastic stresses are applied to different measuring components by adjusting the loading plate driven by the adjusting bolt.

[0067] Furthermore, the stress loading device 1 is made of nylon material; the reference element 31 and the measuring element 30 are made of the same material, the surface of the reference element 31 is coated with epoxy resin, and the electrically insulating surface of the measuring element 30 is coated with epoxy resin.

[0068] Specifically, in this embodiment, the stress loading device 1 is made of high-strength nylon to ensure that galvanic corrosion will not occur between the device and the measuring element during use, thus affecting the measurement results. The surface of the reference element 31 is coated with an epoxy resin coating to form an electrical insulating layer, and the electrical insulating surface of the measuring element 30 is coated with an epoxy resin coating. At the same time, the solder joints between the reference element and the measuring element and the wire are also coated with epoxy resin to achieve electrical insulation, thereby ensuring the accuracy of the simulation test results.

[0069] Example 2

[0070] A monitoring method using the integrated stress corrosion analysis device for marine structures described in this application, characterized by comprising the following steps:

[0071] Step 1: Install multiple sets of measuring components sequentially in the stress loading device, apply different elastic stresses to each set of measuring components through the stress loading device, and place them in the test solution;

[0072] Specifically, multiple sets of measuring components are sequentially installed in the T-shaped measuring component receiving groove 100 of the support frame 10 of the stress loading device 1. In this embodiment, there are 3 sets of measuring components, and 5 sets of strain gauges are set on each set of measuring components. Different forces are applied to each set of measuring components by adjusting the loading plate driven by the bolt (generating different deflections), so that different elastic stresses are generated in each set of measuring components. The elastic stress can be obtained by the strain gauges set on the measuring components. Since the elastic stress is applied by the four-point bending method in this application, the elastic stress is the largest in the area with the largest deflection in the measuring component. In this embodiment, the elastic stress value applied to the corresponding measuring component is obtained by the value of the strain gauge set at the middle position of the measuring component (measuring element or reference element). The device is placed in the test solution (seawater solution or corrosive solution). In this application, the strain gauges, multi-channel micro-resistance measuring device and zero-resistance ammeter are all connected to the signal acquisition device to facilitate the acquisition of different signals.

[0073] Step 2: At set time intervals T, acquire the local stress value σ of each monitoring area of ​​each measuring element through the stress measuring element. cij and the local stress value σ of each monitoring area of ​​each reference element rij ;

[0074] The measuring element and reference element are sequentially connected to the multi-channel micro-resistance measuring device via a relay module to obtain the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij ;

[0075] Where i represents the number of measuring components and j represents the number of monitoring areas;

[0076] Specifically, after placing the device in the test solution, at set time intervals T, the signal acquisition device collects the stress value on each strain gauge, that is, it obtains the local stress value σ of each monitoring area of ​​each measuring element through the stress measuring element. cij and the local stress value σ of each monitoring area of ​​each reference element rij ;

[0077] Then, each measuring element and reference element are sequentially connected to the multi-channel micro-resistance measurement device (constant current source and voltage measurement module) via a relay module to obtain the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij The local resistance value can be obtained from the voltage and current values ​​of the corresponding monitoring area. In this embodiment, i takes the value of 1 to 3 and j takes the value of 1 to 5.

[0078] After collecting relevant data, the relay module is disconnected, which disconnects the measuring component from the multi-channel micro-resistance measuring device. The zero-resistance ammeter connection switch is closed to keep the measuring component in a simulated marine corrosion state.

[0079] Step 3: Based on the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij Obtain the localized metal corrosion Δh in each monitoring area of ​​each measuring element. ij The calculation formula is:

[0080]

[0081]

[0082] in, The local resistance value of the measuring element is measured in the initial stage. h represents the local resistance value of the reference element measured in the initial stage. cij This is the initial thickness value of the measuring element;

[0083] Specifically, the signal acquisition device transmits the acquired signals to the data analysis terminal. The data analysis terminal processes the acquired data to obtain the amount of localized metal corrosion in each monitoring area. The specific process is as follows: the data analysis terminal obtains the local resistance value R of each monitoring area of ​​each measuring element at different times transmitted by the signal acquisition device. cij and the local resistance value R of each monitoring area of ​​each reference element rij Then, the localized metal corrosion Δh in each monitoring area of ​​each measuring element is calculated. ij The calculation formula is:

[0084]

[0085]

[0086] in, The local resistance value of the measuring element is measured in the initial stage. h represents the local resistance value of the reference element measured in the initial stage. cij This is the initial thickness value of the measuring element;

[0087] Step 4: Based on the obtained localized metal corrosion amount Δh ij Calculate the local corrosion rate CR of the measuring element at intervals T. ij The calculation formula is:

[0088] CR ij =Δh ij / T (3);

[0089] Specifically, the data analysis terminal uses the acquired localized metal corrosion amount Δh ij Calculate the local corrosion rate CR of the measuring element at intervals T. ij The calculation formula is:

[0090] CR ij =Δh ij / T (3);

[0091] Step 5: Based on the obtained local corrosion rate CR of the measuring element ij and local stress value σ cij Establish the relationship between the local corrosion rate and the local stress value in each monitoring area;

[0092] Specifically, the data analysis terminal can obtain the local corrosion rate (CR) of the measuring element. ij and local stress value σ cijTo establish the relationship between the local corrosion rate and the local stress value in each monitoring area, the following relationship was established: By setting up a control group, experiments were conducted under no stress conditions to obtain the metal corrosion rate CR0. The relationship between the local corrosion rate and the local stress value is as follows:

[0093] CR σ =k(σ)CR0

[0094] Among them, CR σ The corrosion rate is given by k(σ) under stress σ, where k(σ) is a corrosion rate correction function with respect to stress σ. By fitting the k(σ) function to measured data, the corrosion rate of metal structural components under different stress states can be easily obtained.

[0095] Furthermore, it also includes the local resistance value R of each monitoring area of ​​each measuring element obtained. cij and the local resistance value R of each monitoring area of ​​each reference element rij Calculate the resistance ratio k of each monitoring area of ​​the measuring element and the reference element. ij The calculation formula is:

[0096] k ij =R cij / R rij (4)

[0097] And based on the resistance ratio k of each monitoring region of the measuring element and the reference element ij Obtain the resistance ratio k ij The curve showing the relationship between resistance and time is based on the resistance ratio k. ij The rate of change of resistivity Δk is obtained from the curve of the relationship between resistivity and time. ij ;

[0098] The obtained resistance ratio change rate Δk ij The rate of change of resistance ratio k s A comparison is made to determine whether the measuring element has a crack. The specific determination process is as follows:

[0099] If Δk ij ≥k s Determine if the measuring element has cracked; if Δk ij <k s If the measurement element is intact, it can be determined that no crack has occurred.

[0100] Specifically, the data analysis terminal can also analyze the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij Calculate the resistance ratio k of each monitoring area of ​​the measuring element and the reference element. ijThe calculation formula is:

[0101] k ij =R cij / R rij (4)

[0102] And based on the resistance ratio k of each monitoring region of the measuring element and the reference element ij Obtain the resistance ratio k ij The curve showing the relationship between resistance and time is based on the resistance ratio k. ij The rate of change of resistivity Δk is obtained from the curve of the relationship between resistivity and time. ij ;

[0103] The obtained resistance ratio change rate Δk ij The rate of change of resistance ratio k s A comparison is made to determine whether the measuring element has a crack. The specific determination process is as follows:

[0104] If Δk ij ≥k s Determine if the measuring element has cracked; if Δk ij <k s If the measurement element is intact, it can be determined that no crack has occurred.

[0105] Wherein, the judgment threshold k s The selection method is as follows:

[0106] Without applying elastic stress, the corrosion rate CR0 of the measuring element in the solution environment is obtained. After applying stress σ, based on the relationship between local corrosion rate and local stress value established in step 5, the corrosion rate CR0 under stress σ is calculated. σ Then, at this time, the resistance ratio k between the measuring element and the reference element is... σ The calculation formula is as follows:

[0107]

[0108] Among them, h cij is the initial thickness value of the measuring element, and k is the initial resistance ratio between the measuring element and the reference element in step 3.

[0109] k σ Taking the first derivative with respect to time T, we obtain k. σ The calculation formula is as follows:

[0110]

[0111] Take k s =2~3k σ ', if Δk ij >k s Determine if the measuring element has cracked; if Δkij <Δk s If the resistance ratio of the measuring element to the reference element is not found, it can be determined that no crack has occurred. That is, by monitoring the local resistance ratio of the measuring element and the reference element and plotting the resistance ratio change curve over time, the damage types such as corrosion and stress corrosion cracking of the structure can be effectively identified.

[0112] Furthermore, it also includes the following steps:

[0113] Disconnect all measuring elements and reference elements from the multi-channel micro resistance measuring device by using the relay module, connect the zero resistance ammeter to the measuring element by using the zero resistance ammeter access switch, and connect multiple sets of measuring elements in parallel.

[0114] The thermocouple currents I1 to I2 between each measuring element are obtained sequentially using each zero-resistance galvanometer. i This allows us to obtain information about the galvanic corrosion of the measuring element under different elastic stresses.

[0115] Specifically, all measuring elements are connected in parallel in the solution. When corrosion occurs, electrons from the anode measuring element move towards the cathode measuring element, thus forming a galvanic current I. i The change of galvanic current over time is recorded using a zero-resistance galvanometer to measure the degree of galvanic corrosion and its polarity change process between measuring elements under different elastic stresses.

[0116] If I i If I < 0, the measuring element of this channel is determined to be the anode. i The higher the value, the more severe the galvanic corrosion. If I i When the value is greater than 0, the measuring element of the channel is determined to be the cathode.

[0117] Specifically, the marine structure stress corrosion comprehensive analysis device disclosed in this invention can also be used to simulate local corrosion damage in areas subjected to different loads by combining three sets of loading channels and a galvanic current measurement method, thus closely matching the actual service conditions of marine structures. The specific process is as follows: The electrical connection between all measuring elements and reference elements and the multi-channel micro-resistance measuring device is disconnected via a relay module. A zero-resistance galvanometer is connected to the measuring element via a zero-resistance galvanometer access switch, and multiple sets of measuring elements are connected in parallel. A galvanic cell structure is formed between the multiple measuring elements. Each zero-resistance current will obtain the current value of the corresponding measuring element. The signal acquisition device obtains the data from each galvanometer and transmits it to the data analysis terminal. The data analysis terminal sequentially obtains the galvanic current I1~I2 between each measuring element through each zero-resistance galvanometer. i This allows us to obtain information about the corrosion of the measuring element under different elastic stresses, and thus obtain information about the corrosion of the measuring element under different stresses.

[0118] Example 3

[0119] The difference between this embodiment and Embodiment 2 is that, in Embodiment 2, in order to perform corrosion testing (including corrosion from the test solution and galvanic corrosion between different measuring elements) on multiple measuring elements as a single unit, in step 2, the relay module sequentially connects the measuring elements and the reference element to the multi-channel micro-resistance measuring device to obtain the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij Then, disconnect the relay module to disconnect the measuring component from the multi-channel micro-resistance measuring device, and then close the zero-resistance galvanometer connection switch to keep the measuring component in a simulated marine corrosion state (i.e., a galvanic cell structure is formed between the measuring components, so that it is in both galvanic corrosion and corrosion with the test solution).

[0120] In this embodiment, in order to simulate only the corrosion rate of the measuring element under different elastic stresses (excluding galvanic corrosion between the measuring elements), in step 2, the measuring element and the reference element are sequentially electrically connected to the multi-channel micro-resistance measuring device by the relay module to obtain the local resistance value R of each monitoring area of ​​each measuring element. cij and the local resistance value R of each monitoring area of ​​each reference element rij Afterwards, disconnect the relay module to disconnect the measuring component from the multi-channel micro-resistance measuring device. At the same time, the zero-resistance galvanometer connection switch is always in the open state. The zero-resistance galvanometer connection switch is only closed when the measuring element, including galvanic corrosion, is detected.

[0121] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A comprehensive stress corrosion analysis device for marine structures, characterized in that, include: Stress loading device, multi-channel microresistivity measuring device, and measuring components; The stress loading device is provided with multiple sets of measuring components in sequence, and the stress loading device applies different elastic stresses to the multiple sets of measuring components. Each set of measurement components includes a measuring element, a reference element, and a stress measuring element. The measuring element and the reference element are arranged side by side in the stress loading device and are subjected to the same elastic stress by the stress loading device. Multiple stress measuring elements are provided on the measuring element and the reference element on the stress loading side to form multiple monitoring areas. The positions of the multiple stress measuring elements on the measuring element and the reference element are corresponding. The multi-channel micro-resistance measurement device includes a constant current source, multiple voltage measurement modules, and a relay module. The constant current source is connected to both ends of the measuring element and the reference element to apply a constant current to the measuring element and the reference element. Multiple voltage measurement modules are connected to the measuring element and the reference element to measure the voltage of each monitoring area respectively; The relay module is disposed between the measuring component and the multi-channel micro-resistance measuring device, and is used to electrically connect or disconnect the measuring element and the reference element to the multi-channel micro-resistance measuring device in sequence.

2. The comprehensive stress corrosion analysis device for marine structures according to claim 1, characterized in that: It also includes a zero-resistance galvanometer disposed at one end of each of the measuring elements, and a zero-resistance galvanometer access switch is provided between two adjacent measuring elements.

3. The comprehensive stress corrosion analysis device for marine structures according to claim 2, characterized in that: The measuring element and the reference element have wires welded to their sides at positions corresponding to the monitoring area for electrical connection with the voltage measurement module.

4. The comprehensive stress corrosion analysis device for marine structures according to any one of claims 1 to 3, characterized in that: Both the stress loading device and the reference element have electrically insulating structures on their surfaces. The side of the measuring element opposite to the applied elastic stress is an electro-corrosion surface, and the other parts of the measuring element are provided with an electrically insulating structure.

5. The comprehensive stress corrosion analysis device for marine structures according to claim 4, characterized in that: The stress loading device includes a support frame, a loading plate, and adjusting bolts; The support frame is provided with a T-shaped measuring component receiving slot, and the loading plate is provided in the measuring component receiving slot; The support frame is provided with a plurality of adjusting bolts on one side of the bottom of the measuring component receiving groove. One end of the adjusting bolt is connected to the loading plate. The adjusting bolt can drive the loading plate to move toward the measuring component placed in the measuring component receiving groove to apply elastic stress to the measuring component.

6. The comprehensive stress corrosion analysis device for marine structures according to claim 5, characterized in that: The stress loading device is made of nylon material; the reference element and the measuring element are made of the same material, the surface of the reference element is coated with epoxy resin, and the electrically insulating surface of the measuring element is coated with epoxy resin.

7. A monitoring method using the comprehensive stress corrosion analysis device for marine structures according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Install multiple sets of measuring components sequentially in the stress loading device, apply different elastic stresses to each set of measuring components through the stress loading device, and place them in the test solution; Step 2: At set time intervals The local stress value σ of each monitoring area of ​​each measuring element is obtained through the stress measuring element. cij and the local stress value of each monitoring area of ​​each reference element σ rij ; The measuring element and reference element are sequentially connected to the multi-channel microresistivity measuring device via a relay module to obtain the local resistance value of each monitoring area of ​​each measuring element. and the local resistance value of each monitoring area of ​​each reference element ; Where i represents the number of measuring components and j represents the number of monitoring areas; Step 3: Based on the local resistance value of each monitoring area of ​​each measuring element. and the local resistance value of each monitoring area of ​​each reference element Obtain the amount of localized metal corrosion in each monitoring area of ​​each measuring element. The calculation formula is: （1） （2） in, The local resistance value of the measuring element is measured in the initial stage. The local resistance value of the reference element measured in the initial stage, where h cij This is the initial thickness value of the measuring element; Step 4: Based on the obtained localized metal corrosion amount Calculate every time interval Local corrosion rate of internal measuring elements The calculation formula is: （3）； Step 5: Based on the obtained local corrosion rate of the measuring element and local stress value σ cij Establish the local corrosion rate for each monitoring area. With local stress value σ cij The relationship between them.

8. The monitoring method according to claim 7, characterized in that: It also includes the local resistance value of each monitoring area obtained for each measuring element. and the local resistance value of each monitoring area of ​​each reference element Calculate the resistance ratio of each monitoring area of ​​the measuring element and the reference element. The calculation formula is: （4） And based on the resistance ratio of each monitoring region of the measuring element and the reference element. Obtain the resistance ratio The curve showing the relationship between resistivity and time is based on the resistivity ratio. The rate of change of resistivity is obtained from the curve of the relationship between resistivity and time. ; The obtained resistance ratio change rate Rate of change of resistance ratio compared to the set value A comparison is made to determine whether the measuring element has a crack. The specific judgment process is as follows: like ≥ To determine if the measuring element has cracked; if < If the measurement element is intact, it can be determined that no crack has occurred.

9. The monitoring method according to claim 8, characterized in that: Set resistance ratio change rate The calculation process is as follows: Obtain the corrosion rate CR0 of the measuring element under no elastic stress; obtain the corrosion rate CR of the measuring element under applied elastic stress σ. σ ; Calculate the resistance ratio k of the measuring element and the reference element when elastic stress σ is applied. σ The calculation formula is as follows: （5） Regarding time Find the first derivative to obtain the rate of change of resistivity σ under applied elastic stress. k σ ’ The calculation formula is as follows: （6） Pick .

10. The monitoring method according to claim 9, characterized in that: It also includes the following steps: Disconnect all measuring elements and reference elements from the multi-channel micro resistance measuring device by using the relay module, connect the zero resistance ammeter to the measuring element by using the zero resistance ammeter access switch, and connect multiple sets of measuring elements in parallel. The thermocouple currents I1~I2 between each measuring element are obtained sequentially using each zero-resistance galvanometer. i This allows us to obtain information about the corrosion of the measuring element under different elastic stresses.

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