Ocean structure stress corrosion comprehensive analysis device and monitoring method

Abstract

The invention discloses a comprehensive analysis device and a monitoring method for stress corrosion of an ocean structure. The device comprises a stress loading device, a multi-channel micro-resistance measuring device and a measuring assembly, the stress loading device can apply different elastic stresses to the multiple groups of measuring assemblies; each group of measuring components comprises a measuring element, a reference element and a stress measuring element, and each group of measuring components is provided with a plurality of monitoring areas; the multi-channel micro-resistance measuring device comprises a constant current source, a plurality of voltage measuring modules and a relay module, the multi-channel micro-resistance measuring device can sequentially obtain the resistance of different measuring elements and reference elements at different moments, and then the corrosion rates of the measuring elements under different elastic stresses are obtained. According to the marine structure stress corrosion comprehensive analysis device disclosed by the invention, the corrosion rates of the measuring elements under different elastic stresses can be conveniently obtained, so that the simulation of the corrosion rates of the marine structure under different elastic stresses is realized.

Description

Technical Field

[0001] The invention relates to the technical field of prefabricated pile manufacturing, in particular to a comprehensive analysis device and monitoring method for stress corrosion of marine structures. Background Art

[0002] With the continuous improvement of marine resource development and utilization technology, the load-bearing requirements of marine structures (such as offshore platforms, offshore wind turbines, offshore oil drilling platforms, etc.) are gradually increasing. For large marine structures, the internal stress distribution of the structure is complex. Under the combined effect of stress-corrosion, it will not only accelerate the corrosion rate of metal materials in seawater environments, but also cause risks such as cracks and fractures in the structure. Therefore, reliable comprehensive monitoring and evaluation of the stress-corrosion state of marine structures is particularly important.

[0003] At present, the stress corrosion monitoring of marine structures is mainly carried out by simulating stress loads through bending stress loading devices and obtaining corrosion rates through electrochemical testing technology. However, traditional stress corrosion monitoring technology cannot provide feedback on local corrosion problems of structures under different stress loads, nor can it provide feedback on the impact of stress corrosion cells under different stresses on corrosion development. In addition, traditional stress corrosion monitoring technology is also difficult to capture the formation and expansion of cracks on the surface of the structure, and cannot achieve accurate assessment of the risk of structural damage. Summary of the invention

[0004] In view of the above problems, the present invention proposes a comprehensive analysis device for stress corrosion of marine structures.

[0005] The technical means adopted by the present invention are as follows:

[0006] A comprehensive analysis device for stress corrosion of marine structures, comprising: a stress loading device, a multi-channel micro-resistance measuring device and a measuring component;

[0007] A plurality of groups of measuring components are sequentially arranged in the stress loading device, and the stress loading device applies different elastic stresses to the plurality of groups of measuring components;

[0008] Each group of the measuring components comprises 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 applied with the same elastic stress by the stress loading device. A plurality of the stress measuring elements are arranged on the stress loading side of the measuring element and the reference element to form a plurality of monitoring areas. The positions of the plurality of the stress measuring elements on the measuring element and the reference element correspond to each other.

[0009] The multi-channel micro-resistance measuring device includes a constant current source, a plurality of voltage measuring modules and a relay module. The constant current source is connected to both ends of the measuring element and the reference element for applying a constant current to the measuring element and the reference element; the plurality of voltage measuring modules are connected to the measuring element and the reference element for respectively measuring the voltage of each monitoring area; the relay module is arranged between the measuring component and the multi-channel micro-resistance measuring device for electrically connecting or disconnecting the measuring element and the reference element with the multi-channel micro-resistance measuring device in turn.

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

[0011] Furthermore, wires for electrically connecting to the voltage measurement module are welded at positions corresponding to the monitoring areas on the side surfaces of the measuring element and the reference element.

[0012] Furthermore, the surfaces of the stress loading device and the reference element are both provided with electrical insulation structures;

[0013] The side surface of the measuring element opposite to the one where the elastic stress is applied is an electrical corrosion surface, and the other parts of the measuring element are provided with an electrical insulation structure.

[0014] Furthermore, the stress loading device comprises a support frame, a loading plate and an adjusting bolt;

[0015] A T-shaped measuring component accommodating groove is provided in the support frame, and the loading plate is provided in the measuring component accommodating groove;

[0016] A plurality of adjusting bolts are provided on the support frame at one side of the bottom of the measuring component accommodating groove, one end of each adjusting bolt is connected to the loading plate, and the adjusting bolt can drive the loading plate to move toward the side of the measuring component placed in the measuring component accommodating 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 reference element surface is provided with an epoxy resin coating, and the electrical insulation surface of the measuring element is provided with an epoxy resin coating.

[0018] A monitoring method using the marine structure stress corrosion comprehensive analysis device described in the present application is characterized by comprising the following steps:

[0019] Step 1, installing multiple groups of measuring components in a stress loading device in sequence, applying different elastic stresses to each group of measuring components through the stress loading device, and placing them in a test solution;

[0020] Step 2: At every set time interval T, 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 σ of each monitoring area of ​​each reference element rij ;

[0021] The measuring element and the reference element are electrically connected to the multi-channel micro-resistance measuring device in sequence through 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 ;

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

[0023] Step 3: According to 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 local metal corrosion amount Δh in each monitoring area of ​​each measuring element ij , the calculation formula is:

[0024]

[0025]

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

[0027] Step 4: According to the obtained local corrosion amount of metal Δh ij Calculate the local corrosion rate CR of the measuring element within each time interval T ij , the calculation formula is:

[0028] CR ij =Δh ij / T (3);

[0029] Step 5: According to the local corrosion rate CR of the measured element ij and the local stress value σ cij , establish the local corrosion rate CR of each monitoring area ij The relationship between and the local stress value σ.

[0030] Furthermore, the method further comprises: obtaining the local resistance value R of each monitoring area of ​​each measuring element according to the obtained local resistance value R 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 according to the resistance ratio k of each monitoring area of ​​the measuring element and the reference element ij Obtain the resistance ratio k ij The relationship curve with time, according to the resistance ratio k ij The relationship curve with time obtains the resistance ratio change rate Δk ij ;

[0033] And the resistance ratio change rate Δk ij The change rate of the resistance ratio k s Compare to determine whether the measuring element has cracks. The specific judgment process is as follows:

[0034] If Δk ij ≥k s , judge that the measuring element has cracks; if Δk ij <k s , it is judged that the measuring element has no cracks.

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

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

[0037]

[0038] k σ Take the first-order derivative of time T to obtain the resistance ratio change rate k of the applied elastic stress σ σ 'The calculation formula is as follows:

[0039]

[0040] Take ks=2~3kσ.

[0041] Furthermore, the method further comprises the following steps:

[0042] Disconnect all measuring elements and reference elements from the multi-channel micro-resistance measuring device through a relay module, connect a zero-resistance ammeter to the measuring element through a zero-resistance ammeter access switch, and connect multiple groups of measuring elements in parallel;

[0043] Through each zero resistance ammeter, the electric couple current I1~I between each measuring element is obtained in turn. i , thus obtaining the corrosion conditions of the measuring element under different elastic stresses.

[0044] Compared with the prior art, the stress corrosion comprehensive analysis device for marine structures disclosed in the present invention has the following beneficial effects: the stress corrosion comprehensive analysis device for marine structures disclosed in the present invention, because multiple groups of measuring components are arranged on the stress loading device and different elastic stresses can be applied to each group of measuring components, and the resistance value of each monitoring area of ​​each measuring element and reference element is obtained through a multi-channel micro-resistance measuring device, so that the corrosion rate of the measuring element under different elastic stresses can be easily obtained, thereby realizing the simulation of the corrosion rate of the marine structure under different elastic stresses. That is, the local corrosion damage of different areas subjected to different loads can be simulated, which is in line with the actual service conditions of the marine structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is an axial view of a stress loading device of a comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention;

[0046] Figure 2 It is an end view of the stress loading device of the comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention;

[0047] Figure 3 It is a schematic diagram of the connection between the measuring component and the multi-channel micro-electric measuring device, the zero-resistance ammeter and the zero-resistance ammeter access switch in the comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention;

[0048] Figure 4 The present invention is a schematic diagram of the connection between the measuring element and the voltage measuring module in the comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention.

[0049] In the figure: 1. stress loading device; 10. support frame; 100. test component accommodating groove; 11. loading plate; 110. convex rib; 12. adjusting bolt; 13. supporting roller; 2. multi-channel micro-resistance measuring device; 20. constant current source; 21. voltage measuring module; 22. relay module; 3. measuring component; 30. measuring element; 31. reference element; 32. stress measuring element; 33. monitoring area; 40. zero resistance ammeter; 41. zero resistance ammeter access switch. DETAILED DESCRIPTION

[0050] Example 1

[0051] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention comprises: 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 a plurality of groups of the measuring components 3 in sequence, and the stress loading device 1 applies different elastic stresses to the plurality of groups of the measuring components 3;

[0053] Each group of the measuring 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 applied with the same elastic stress by the stress loading device 1. A plurality of the stress measuring elements 32 are arranged on the stress loading side of the measuring element 30 and the reference element 31 to form a plurality of monitoring areas 33. The positions of the plurality of the stress measuring elements 32 on the measuring element 30 and the reference element 31 correspond to each other.

[0054] The multi-channel micro-resistance measuring device 2 includes a constant current source 20, a plurality of voltage measuring 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 plurality of voltage measuring 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 arranged between the measuring component 3 and the multi-channel micro-resistance measuring device 2, and is used to electrically connect or disconnect the measuring element 30 and the reference element 31 with the multi-channel micro-resistance measuring device 2 in sequence.

[0055] Specifically, the marine structure stress corrosion comprehensive analysis device disclosed in the present invention comprises a stress loading device 1, on which a plurality of measurement components 3 are installed. Figure 1As shown in , in this embodiment, the number of measuring components 3 is 3 groups, and the specific number of measuring components can be set as needed. The stress loading device 1 can apply a force to the measuring component 3 so that the measuring component 3 generates elastic deformation and then generates 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 respectively, so as to simulate the load conditions of the metal structure 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, and the measuring element 30 and the reference element 31 are arranged in parallel. 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, so that the measuring element 30 and the reference element 31 are bent and generate elastic stress. A plurality of stress measuring elements 32 are evenly arranged on the side surface of the measuring element 30 and the reference element 31 to which the force is applied to form a plurality of monitoring areas 33. In this embodiment, the stress measuring element 32 adopts a strain gauge, Figure 1As shown in , the measuring element 30 and the reference element 31 are each provided with 5 strain gauges to form 5 monitoring areas. The position of the strain gauge on the measuring element 30 corresponds to the position of the strain gauge on the reference element 31 to ensure that the positions of 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, and 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 both ends of the measuring element 30 and the reference element 31 through a wire for applying 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 respectively. In this embodiment, the voltage measurement module includes 5 voltmeters, and the 5 voltmeters are respectively connected to both ends of the 5 monitoring areas to measure the voltage of each monitoring area 33. The relay module 22 is arranged between the measuring assembly 3 and the multi-channel micro-resistance measuring device 2 (constant current source and voltage measuring module), and is used to electrically connect or disconnect the measuring element 30 and the reference element 31 with the multi-channel micro-resistance measuring device 2 (constant current source and voltage measuring module) in sequence. In this embodiment, the relay module is a 6-way switch, which is used to electrically connect or disconnect each measuring element and the reference element with the multi-channel micro-resistance measuring device 2, respectively, so that the resistance value of each monitoring area of ​​each measuring element and the reference element can be obtained by the multi-channel micro-resistance device. The comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention, because multiple groups of measuring assemblies are arranged on the stress loading device and different elastic stresses can be applied to each group of measuring assemblies, and the resistance value of each monitoring area of ​​each measuring element and the reference element is obtained by the multi-channel micro-resistance measuring device, so that the corrosion rate of the measuring element under different elastic stresses can be conveniently obtained, and then the simulation of the corrosion rate of the marine structure when subjected to different elastic stresses can be realized. It can simulate the local corrosion damage of different load-bearing areas, which fits the actual service conditions of marine structures.

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

[0057] Specifically, in this embodiment, a zero-resistance ammeter 40 is further provided at one end of each measuring element 30, and a zero-resistance ammeter access switch 41 is provided between two adjacent measuring elements 30. The zero-resistance ammeter access switch can be used to connect or disconnect one ends of multiple measuring elements to each other, and connect or disconnect the zero-resistance ammeter to the measuring element at the same time. When the zero-resistance ammeter is connected to the measuring element, the current in the corresponding measuring element can be measured. In this embodiment, by setting a zero-resistance ammeter 40 and a zero-resistance ammeter access switch 41, the corrosion condition of the measuring element under different elastic stresses can be realized. Specifically, when it is necessary to set a zero-resistance ammeter 40 and a zero-resistance ammeter access switch 41 to realize the corrosion condition 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 a test solution (corrosive solution), and the zero-resistance ammeter access switch 41 is closed so that the zero-resistance ammeter 40 is connected to the measuring element, and a primary cell structure is formed between the multiple measuring elements, so that the corrosion condition of the different measuring elements is obtained according to the reading of each zero-resistance ammeter, and the corrosion condition of the measuring element under different stresses can be obtained.

[0058] Furthermore, wires for electrically connecting to the voltage measurement module 21 are welded at positions corresponding to the monitoring area 33 on the side surfaces of the measuring element 30 and the reference element 31 .

[0059] Specifically, in this embodiment, in order to ensure the accuracy of the measurement results and ensure that the connection between the wire and the measuring element and the reference element does not affect the simulation test results, the wire is welded at the position corresponding to the monitoring area on the side of the measuring element and the reference element, and the other end of the wire is connected to the wiring terminal of the corresponding voltage measurement module, and the wire for electrical connection to the constant current source is welded on the two end surfaces 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 surface of the measuring element 30 opposite to the one where the elastic stress is applied is an electrical corrosion surface, and the other parts of the measuring element 30 are provided with an electrical insulation structure.

[0062] Specifically, in this embodiment, the measuring element and the reference element are made of the same material, and the specifications of the measuring element and the reference element are consistent, so as to ensure that the elastic stress generated in the measuring element and the reference element is consistent, and the outer surfaces of the reference element and the stress loading device are both electrically insulating structures, which can ensure that during the simulation experiment, the reference element and the stress loading device will not generate galvanic corrosion with the measuring element, thereby ensuring the accuracy of the measurement results. The side surface of the measuring element opposite to the elastic stress is the electrical corrosion surface (test surface), and the other parts of the test element are electrically insulating structures, thereby ensuring the accuracy of the simulation results.

[0063] Furthermore, the stress loading device 1 comprises 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 accommodating groove 100, one end of the adjusting bolts 12 is connected to the loading plate 11, and the adjusting bolts 12 can drive the loading plate 11 to move toward the side of the measuring component 3 placed in the measuring component accommodating 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 accommodating groove 100 is provided on one side of the support frame 10. A plurality of threaded holes are provided at the bottom of the measuring component accommodating groove 100 along the length direction of the accommodating groove. The adjusting bolt 12 is installed in the threaded hole. A loading plate 11 is provided at one end of the adjusting bolt 12 placed in the measuring component accommodating groove. 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 group of measuring components. Two convex ribs 110 structures are provided on the side of the loading plate 11 facing the measuring components. The direction of the convex ribs is consistent with the width direction of the measuring components. When the measuring assembly is arranged in the measuring assembly receiving groove, the two ends of the measuring assembly (measuring element and reference element) are respectively inserted into the two ends of the T-shaped measuring assembly receiving groove. Preferably, support rollers 13 are arranged at both ends of the T-shaped measuring assembly receiving groove, so that a four-point bending structure is formed between the measuring element and the reference element and the stress loading device, and a force is applied to the measuring assembly through the four-point bending structure to bend it and generate elastic stress. Multiple groups of measuring assemblies are arranged in sequence along the length direction of the groove in the measuring assembly receiving groove, and different elastic stresses are applied to different measuring assemblies by driving the loading plate through 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 provided with an epoxy resin coating, and the electrical insulation surface of the measuring element 30 is provided with an epoxy resin coating.

[0068] Specifically, in this embodiment, the material used for the stress loading device 1 is high-strength nylon, ensuring that the device and the measuring element will not be galvanically corroded during use to affect the measurement results. The surface of the reference element 31 is coated with an epoxy resin coating to form an electrical insulation layer, and the electrical insulation surface of the measuring element 30 is coated with an epoxy resin coating. At the same time, the reference element and the measuring element and the wire welding points 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 marine structure stress corrosion comprehensive analysis device described in the present application is characterized by comprising the following steps:

[0071] Step 1, installing multiple groups of measuring components in a stress loading device in sequence, applying different elastic stresses to each group of measuring components through the stress loading device, and placing the measuring components in a test solution;

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

[0073] Step 2: At every set time interval T, 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 σ of each monitoring area of ​​each reference element rij ;

[0074] The measuring element and the reference element are electrically connected to the multi-channel micro-resistance measuring device in sequence through 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 ;

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

[0076] Specifically, after the device is placed in the test solution, at a set time interval T, the signal acquisition device collects the stress value on each strain gauge, that is, 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 σ of each monitoring area of ​​each reference element rij ;

[0077] Then, each measuring element and reference element are electrically connected to the multi-channel micro-resistance measuring device (constant current source and voltage measurement module) in turn through 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 , the local resistance value can be obtained from the voltage value and current value of the corresponding monitoring area. In this embodiment, i is 1 to 3, and j is 1 to 5;

[0078] After collecting relevant data, disconnect the relay module to disconnect the measuring component from the multi-channel micro-resistance measuring device, and close the zero-resistance ammeter access switch to keep the measuring component in a simulated marine corrosion state;

[0079] Step 3: According to 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 local metal corrosion amount Δh in each monitoring area of ​​each measuring element ij , the calculation formula is:

[0080]

[0081]

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

[0083] Specifically, the signal acquisition device transmits the collected signals to the data analysis terminal, which can process the acquired data and obtain the local corrosion amount of metal 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 , and then calculate the local corrosion amount of metal in each monitoring area of ​​each measuring element Δh ij , the calculation formula is:

[0084]

[0085]

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

[0087] Step 4: According to the obtained local corrosion amount of metal Δh ij Calculate the local corrosion rate CR of the measuring element within each time interval T ij , the calculation formula is:

[0088] CR ij =Δh ij / T (3);

[0089] Specifically, the data analysis terminal obtains the local corrosion amount of the metal Δh ij Calculate the local corrosion rate CR of the measuring element within each time interval T ij , the calculation formula is:

[0090] CR ij =Δh ij / T (3);

[0091] Step 5: According to the local corrosion rate CR of the measured element ij and the 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 the local stress value σ cij, establish the relationship between the local corrosion rate and the local stress value of each monitoring area, and the relationship is established as follows: by setting up a group of control groups, the test is carried out under the condition of no stress, and the metal corrosion rate CR0 is obtained at this time. The relationship between the local corrosion rate and the local stress value is:

[0093] CR σ =k(σ)CR0

[0094] Among them, CR σ is the corrosion rate under stress value σ, and k(σ) is the corrosion rate correction coefficient function about stress σ. The k(σ) function is fitted based on the measured data, so that the corrosion rate of metal structural parts under different stress states can be easily obtained.

[0095] Furthermore, the method further comprises: obtaining the local resistance value R of each monitoring area of ​​each measuring element according to the obtained local resistance value R 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 according to the resistance ratio k of each monitoring area of ​​the measuring element and the reference element ij Obtain the resistance ratio k ij The relationship curve with time, according to the resistance ratio k ij The relationship curve with time obtains the resistance ratio change rate Δk ij ;

[0098] And the resistance ratio change rate Δk ij The change rate of the resistance ratio k s Compare to determine whether the measuring element has cracks. The specific judgment process is as follows:

[0099] If Δk ij ≥k s , judge that the measuring element has cracks; if Δk ij <k s , it is judged that the measuring element has no cracks.

[0100] Specifically, the data analysis terminal can also obtain the local resistance value R of each monitoring area of ​​each measuring element according to the 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:

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

[0102] And according to the resistance ratio k of each monitoring area of ​​the measuring element and the reference element ij Obtain the resistance ratio k ij The relationship curve with time, according to the resistance ratio k ij The relationship curve with time obtains the resistance ratio change rate Δk ij ;

[0103] And the resistance ratio change rate Δk ij The change rate of the resistance ratio k s Compare to determine whether the measuring element has cracks. The specific judgment process is as follows:

[0104] If Δk ij ≥k s , judge that the measuring element has cracks; if Δk ij <k s , it is judged that the measuring element has no cracks.

[0105] Among them, 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 the local corrosion rate and the local stress value established in step 5, the corrosion rate CR under the stress σ is calculated. σ , then the resistance ratio k of 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 of the measuring element to the reference element in step 3.

[0109] k σ Take the first-order derivative with respect to time T and obtain k σ 'The calculation formula is as follows:

[0110]

[0111] Take k s =2~3k σ ', if Δk ij >k s , judge that the measuring element has cracks; if Δkij <Δk s , it is judged that the measuring element has no cracks; that is, by monitoring the local resistance ratio of the measuring element and the reference element and drawing a curve of the resistance ratio changing with time, the damage types such as corrosion and stress corrosion cracking of the structure can be effectively identified.

[0112] Furthermore, the method further comprises the following steps:

[0113] Disconnect all measuring elements and reference elements from the multi-channel micro-resistance measuring device through a relay module, connect a zero-resistance ammeter to the measuring element through a zero-resistance ammeter access switch, and connect multiple groups of measuring elements in parallel;

[0114] Through each zero resistance ammeter, the electric couple current I1~I between each measuring element is obtained in turn. i , so as to obtain the galvanic corrosion of the measuring element under different elastic stresses.

[0115] Specifically, all measuring elements are connected in parallel in the solution. When the element corrodes, the electrons of the measuring element as the anode move to the measuring element as the cathode, thereby forming a galvanic current I i The variation of the galvanic current over time is recorded by a zero resistance ammeter to measure the degree of galvanic corrosion between the measuring elements under different elastic stresses and the process of polarity change.

[0116] If I i <0, the measuring element of this channel is judged to be the anode. At this time, I i The larger the value, the more serious the galvanic corrosion. i When >0, the measuring element of the channel is judged to be the cathode.

[0117] Specifically, the comprehensive analysis device for stress corrosion of marine structures disclosed in the present invention can also be used to simulate the local corrosion damage of different areas subjected to different loads by combining three groups of loading channels and galvanic current measurement methods, so as to fit the actual service conditions of marine structures. The specific process is as follows: disconnect the electrical connection between all measuring elements and reference elements and the multi-channel micro-resistance measuring device through the relay module, connect the zero-resistance ammeter to the measuring element through the zero-resistance ammeter access switch, and connect multiple groups of measuring elements in parallel to form a primary battery structure between multiple measuring elements. Each zero-resistance current will obtain the current value of the corresponding measuring element. The signal acquisition device obtains the data of each ammeter and transmits it to the data analysis terminal. The data analysis terminal obtains the galvanic current I1~I between each measuring element in turn through each zero-resistance ammeter. i , so as to obtain the corrosion conditions of the measuring element under different elastic stresses, and also to obtain the corrosion conditions 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 be able to perform corrosion tests on multiple measuring elements as an integral component (including corrosion of the test solution and galvanic corrosion between different measuring elements), it is necessary to electrically connect the measuring elements and the reference elements to the multi-channel micro-resistance measuring device in sequence by the relay module in step 2 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 Finally, disconnect the relay module to disconnect the measuring component from the multi-channel micro-resistance measuring device, and then close the zero-resistance ammeter access 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 they are in a state of 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 when it is subjected to different elastic stresses (excluding the galvanic corrosion between the measuring elements), in step 2, the relay module electrically connects the measuring element and the reference element to the multi-channel micro-resistance measuring device in sequence 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 After that, the relay module is disconnected to disconnect the measuring component from the multi-channel micro-resistance measuring device. At the same time, the zero-resistance ammeter access switch is always in the disconnected state. The zero-resistance ammeter access switch is closed only when the measuring element including galvanic corrosion is obtained.

[0121] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A comprehensive analysis device for stress corrosion of marine structures, characterized in that: include: Stress loading device, multi-channel micro-resistance measuring device and measuring assembly; A plurality of groups of measuring components are sequentially arranged in the stress loading device, and the stress loading device applies different elastic stresses to the plurality of groups of measuring components; Each group of the measuring components comprises 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 applied with the same elastic stress by the stress loading device. A plurality of the stress measuring elements are arranged on the stress loading side of the measuring element and the reference element to form a plurality of monitoring areas. The positions of the plurality of the stress measuring elements on the measuring element and the reference element correspond to each other. The multi-channel micro-resistance measuring device comprises a constant current source, a plurality of voltage measuring modules and a relay module, wherein 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; A plurality of voltage measurement modules are connected to the measurement element and the reference element, and are used to measure the voltage of each monitoring area respectively; The relay module is arranged 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 with the multi-channel micro-resistance measuring device in sequence.

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

3. The comprehensive analysis device for stress corrosion of marine structures according to claim 2 is characterized in that: Wires for electrically connecting to the voltage measurement module are welded at positions corresponding to the monitoring areas on the side surfaces of the measuring element and the reference element.

4. The comprehensive analysis device for stress corrosion of marine structures according to any one of claims 1 to 3, characterized in that: The surfaces of the stress loading device and the reference element are both provided with electrical insulation structures; The side surface of the measuring element opposite to the one where the elastic stress is applied is an electrical corrosion surface, and the other parts of the measuring element are provided with an electrical insulation structure.

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

6. The comprehensive analysis device for stress corrosion of 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 provided with an epoxy resin coating, and the electrical insulation surface of the measuring element is provided with an epoxy resin coating.

7. A monitoring method using the marine structure stress corrosion comprehensive analysis device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, installing multiple groups of measuring components in a stress loading device in sequence, applying different elastic stresses to each group of measuring components through the stress loading device, and placing them in a test solution; Step 2: At every set time interval T, 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 σ of each monitoring area of ​​each reference element rij ; The measuring element and the reference element are electrically connected to the multi-channel micro-resistance measuring device in sequence through 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 ; Where i represents the number of measurement components and j represents the number of monitoring areas; Step 3: According to 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 local metal corrosion amount Δh in each monitoring area of ​​each measuring element ij , the calculation formula is: in, is the local resistance value of the measuring element measured at the initial stage, is the local resistance value of the reference element measured at the initial stage, where h cij is the initial thickness value of the measuring element; Step 4: According to the obtained local corrosion amount of metal Δh ij Calculate the local corrosion rate CR of the measuring element within each time interval T ij , the calculation formula is: CR ij =Δh ij / T (3); Step 5: Based on the local corrosion rate CR and local stress value σ of the measured element cij , the relationship between the local corrosion rate CR and the local stress value σ in each monitoring area is established.

8. The monitoring method according to claim 7, characterized in that: 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: k ij =R cij / R rij (4) And according to the resistance ratio k of each monitoring area of ​​the measuring element and the reference element ij Obtain the resistance ratio k ij The relationship curve with time, according to the resistance ratio k ij The relationship curve with time obtains the resistance ratio change rate Δk ij ; And the resistance ratio change rate Δk ij The change rate of the resistance ratio k s Compare to determine whether the measuring element has cracks. The specific judgment process is as follows: If Δk ij ≥k s , judge that the measuring element has cracks; if Δk ij <k s , it is judged that the measuring element has no cracks.

9. The monitoring method according to claim 8, characterized in that: Set the resistance ratio change rate k s The calculation process is as follows: Obtain the corrosion rate CR0 of the measuring element when no elastic stress is applied; obtain the corrosion rate CR of the measuring element when elastic stress σ is applied σ ; Calculate the resistance ratio k of the measuring element and the reference element when the elastic stress σ is applied σ , the calculation formula is as follows: k σ Take the first-order derivative of time T to obtain the resistance ratio change rate k of the applied elastic stress σ σ 'The calculation formula is as follows: Take k s =2~3k σ '.

10. The monitoring method according to claim 9, characterized in that: The following steps are also included: Disconnect all measuring elements and reference elements from the multi-channel micro-resistance measuring device through a relay module, connect a zero-resistance ammeter to the measuring element through a zero-resistance ammeter access switch, and connect multiple groups of measuring elements in parallel; Through each zero resistance ammeter, the electric couple current I1~I between each measuring element is obtained in turn. i , thus obtaining the corrosion conditions of the measuring element under different elastic stresses.

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