A method and system for calculating temperature fatigue damage in bridge structures

Abstract

This invention relates to the field of bridge engineering technology, specifically to a method and system for calculating temperature fatigue damage. The method includes the following steps: establishing daily temperature curves for the top and bottom slabs based on measured temperatures over a set time period; obtaining the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom slabs, and the absolute value of the maximum negative vertical temperature difference between the top and bottom slabs based on the daily temperature curves; determining the daily equivalent temperature stress amplitude based on the daily absolute values ​​of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom slabs, and the maximum negative vertical temperature difference between the top and bottom slabs; and calculating the temperature fatigue damage of the bridge structure based on the S-N curve and the daily equivalent temperature stress amplitude. This invention provides a method and system for calculating temperature fatigue damage, which can solve the problem of the need for highly computational equipment and the difficulty in calculating temperature fatigue in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a method and system for calculating temperature fatigue damage. Background Technology

[0002] In recent years, my country's economy has developed rapidly, and its social productivity has continuously improved, resulting in remarkable achievements in bridge construction. Currently, my country's bridge construction and design technologies have basically reached international advanced levels. During the old China era, the country's economic level was low, and its production technology and capacity could not meet the demands of large-scale infrastructure construction. Most steel bridges had simple structures and poor quality. After the founding of the People's Republic of my country, the country overcame the problem of a weak heavy industry base, rapidly increased steel production, and established a relatively complete industrial system. Since the reform and opening up, my country's economic strength has taken off, its industrial production level has rapidly improved, and bridge design theory, construction technology, and building materials have continuously developed. In steel bridge design standards, China has drawn on foreign specifications and continuously explored new approaches combined with its own national conditions. During this period, China independently designed and constructed a series of large bridges that broke various records.

[0003] As bridge construction progresses, some bridges in my country have entered a stage of performance degradation. Researching methods to extend the service life of bridge structures and other infrastructure has become an urgent problem to be solved.

[0004] Due to the influence of changing temperature fields, temperature effects cause temperature fatigue damage to bridge structures. Traditional methods for calculating temperature fatigue based on measured temperatures require equipment with high computing power, and the calculation process is cumbersome. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for calculating temperature fatigue damage, thereby solving the problem of difficulty in fatigue verification in existing technologies. To achieve the above objective, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides a method for calculating temperature fatigue damage of bridge structures, comprising the following steps:

[0007] Based on the measured top and bottom temperatures within a set time period, establish daily top and bottom temperature curves.

[0008] Based on the daily temperature curves of the top plate and the bottom plate within a set time period, obtain the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates for each day.

[0009] The daily equivalent temperature stress amplitude is determined based on the absolute value of the overall temperature difference, the maximum positive temperature difference between the top and bottom plates, and the absolute value of the maximum negative temperature difference between the top and bottom plates.

[0010] based onSN The curve is used to calculate the temperature fatigue damage of the bridge structure based on the daily equivalent temperature stress amplitude.

[0011] In some alternative schemes, the absolute value of the overall temperature difference, the maximum positive temperature difference in the vertical direction of the top and bottom plates, and the maximum negative temperature difference in the vertical direction of the top and bottom plates are obtained daily to calculate the temperature fatigue damage of other bridge structures within a set range where the temperature environment differs from the measured bridge temperature environment.

[0012] In some alternative solutions, determining the daily equivalent temperature stress amplitude based on the absolute value of the overall daily temperature difference, the absolute values ​​of the maximum positive vertical temperature difference between the top and bottom plates, and the absolute values ​​of the maximum negative vertical temperature difference between the top and bottom plates includes:

[0013] Establish a finite element model to analyze and calculate the correspondence between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive vertical temperature difference of the top and bottom plates and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative vertical temperature difference of the top and bottom plates and the maximum negative temperature difference stress amplitude.

[0014] Based on the correspondence between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive vertical temperature difference of the top and bottom plates and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative vertical temperature difference of the top and bottom plates and the maximum negative temperature difference stress amplitude, the daily equivalent temperature stress amplitude is determined.

[0015] In some alternative solutions, the correspondence between the absolute value of the overall temperature difference and the amplitude of the overall temperature difference stress is as follows: ,in, The overall temperature difference stress amplitude caused by the absolute value of the overall temperature difference on day i. This is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference. This represents the absolute value of the overall temperature difference.

[0016] In some alternative solutions, the correspondence between the maximum vertical positive temperature difference between the top and bottom plates and the maximum positive temperature difference stress amplitude is as follows: ,in, Let be the maximum positive temperature difference stress amplitude caused by the maximum positive temperature difference between the top and bottom plates on day i. It is the ratio of the maximum positive temperature difference stress amplitude to the maximum vertical positive temperature difference between the top and bottom plates. This represents the absolute value of the maximum positive vertical temperature difference between the top and bottom plates.

[0017] In some alternative solutions, the correspondence between the absolute value of the maximum vertical negative temperature difference between the top and bottom plates and the amplitude of the maximum negative temperature difference stress is as follows: ,in, Let be the maximum negative temperature difference stress amplitude caused by the maximum vertical negative temperature difference between the top and bottom plates on day i. It is the ratio of the maximum negative temperature difference stress amplitude to the maximum vertical negative temperature difference of the base plate. This represents the absolute value of the maximum negative temperature difference between the top and bottom plates in the vertical direction.

[0018] In some alternative solutions, determining the daily equivalent temperature stress amplitude based on the correspondence between the absolute value of the daily overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive vertical temperature difference of the top and bottom plates and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative vertical temperature difference of the top and bottom plates and the maximum negative temperature difference stress amplitude includes:

[0019] According to the formula: Determine the daily equivalent temperature stress amplitude ;

[0020] in, For the total number of days in the statistics, The overall temperature difference stress amplitude caused by the absolute value of the overall temperature difference on day i. Let be the maximum positive temperature difference stress amplitude caused by the maximum positive temperature difference between the top and bottom plates on day i. Let be the maximum negative temperature difference stress amplitude caused by the maximum vertical negative temperature difference between the top and bottom plates on day i. It is the sum of the overall temperature difference stress amplitude, the maximum negative temperature difference stress amplitude, and the maximum positive temperature difference stress amplitude. , This is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference. It is the ratio of the maximum positive temperature difference stress amplitude to the maximum vertical positive temperature difference between the top and bottom plates. It is the ratio of the maximum negative temperature difference stress amplitude to the maximum vertical negative temperature difference of the base plate.

[0021] In some optional solutions, the step of establishing daily top and bottom temperature curves based on top and bottom temperatures within a set time period includes:

[0022] Collect the top and bottom plate temperatures within a set time period;

[0023] Based on the top plate temperature and bottom plate temperature within a set time period, fit the daily top plate temperature function and bottom plate temperature function;

[0024] Based on the daily top plate temperature function and bottom plate temperature function, establish the daily top plate temperature curve and bottom plate temperature curve.

[0025] In some alternative schemes, the absolute value of the overall daily temperature difference is the absolute value of the difference between the top plate temperature value at the peak of the daytime temperature fluctuation of the steel box girder section and the bottom plate temperature value at the trough of the nighttime temperature fluctuation of the steel box girder section. The absolute value of the maximum negative vertical temperature difference between the top and bottom plates is the absolute value of the difference between the trough of the top plate temperature curve and the trough of the bottom plate temperature curve. The absolute value of the maximum positive vertical temperature difference between the top and bottom plates is the absolute value of the difference between the peak of the top plate temperature curve and the peak of the bottom plate temperature curve.

[0026] On the other hand, the present invention also provides a bridge structure temperature fatigue damage calculation system, comprising:

[0027] The temperature curve module is used to generate daily top and bottom temperature curves based on the top and bottom temperatures within a set time period.

[0028] The temperature difference determination module is used to obtain the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates based on the temperature curves of the top plate and the bottom plate each day within a set time period.

[0029] The equivalent temperature stress amplitude determination module is used to determine the daily equivalent temperature stress amplitude based on the absolute value of the overall temperature difference, the absolute value of the maximum positive temperature difference in the vertical direction of the top and bottom plates, and the absolute value of the maximum negative temperature difference in the vertical direction of the top and bottom plates.

[0030] The temperature fatigue damage determination module is used for determining damage based on... SN The curve is used to calculate the temperature fatigue damage of the bridge structure based on the daily equivalent temperature stress amplitude.

[0031] Compared with the prior art, the advantages of this invention are as follows: Based on the top and bottom plate temperatures within a set time period, daily top and bottom plate temperature curves are established; based on the daily top and bottom plate temperature curves within the set time period, the absolute value of the overall temperature difference, the absolute value of the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates are obtained; based on the absolute value of the overall temperature difference, the absolute value of the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates, the daily equivalent temperature stress amplitude is determined; based on... SN The curve is used to calculate the temperature fatigue damage of bridge structures based on the daily equivalent temperature stress amplitude. The calculation method is simple and does not require equipment with high computing power, which can improve calculation efficiency and save costs. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the method for calculating the temperature fatigue damage of bridge structures in an embodiment of the present invention;

[0034] Figure 2 As described in the embodiments of the present invention , and Relationship diagram;

[0035] Figure 3 This is a schematic diagram of the temperature breakdown at the temperature peak in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the temperature breakdown at the temperature valley in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the SN curve in an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, this invention provides a method for calculating temperature fatigue damage in bridge structures, comprising the following steps:

[0041] S1: Based on the measured top and bottom plate temperatures within a set time period, establish daily top and bottom plate temperature curves.

[0042] Step S1 specifically includes:

[0043] S11: Collect the top plate temperature and bottom plate temperature within a set time period.

[0044] S12: Based on the top plate temperature and bottom plate temperature within a set time period, fit the daily top plate temperature function and bottom plate temperature function.

[0045] S13: Based on the daily top plate temperature function and bottom plate temperature function, establish the daily top plate temperature curve and bottom plate temperature curve.

[0046] like Figure 2As shown, S2: Based on the daily temperature curves of the top plate and the bottom plate within a set time period, obtain the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates for each day.

[0047] In some alternative embodiments, the absolute value of the overall daily temperature difference is the absolute value of the difference between the top plate temperature value at the peak of the daytime temperature fluctuation of the steel box girder section and the bottom plate temperature value at the trough of the nighttime temperature fluctuation of the steel box girder section.

[0048] In some optional embodiments, the absolute value of the maximum vertical negative temperature difference between the top and bottom plates is the absolute value of the difference between the trough of the top plate temperature curve and the trough of the bottom plate temperature curve, and the absolute value of the maximum vertical positive temperature difference between the top and bottom plates is the absolute value of the difference between the peak of the top plate temperature curve and the peak of the bottom plate temperature curve.

[0049] In this example, the temperature field of the bridge structure is a superposition of the overall temperature difference and the gradient temperature. Since the stress generated by temperature is within the elastic range of the material, the temperature stress under the overall temperature difference and the temperature stress under the gradient temperature can be linearly superimposed. To meet the requirements of a simple and easy-to-calculate temperature fatigue load model, the gradient temperature effect over a day is represented by vertical positive gradient temperature and vertical negative gradient temperature. According to the vertical positive temperature gradient model and the vertical negative temperature gradient model, when a temperature gradient exists in the steel box girder section, the temperature value of the steel box girder section is non-negative. According to the vertical temperature gradient distribution model, the section temperature values ​​at the temperature peak and temperature trough are decomposed. At the temperature peak, it is decomposed into an overall section temperature value and a negative gradient temperature; the decomposed overall section temperature value at the temperature peak is the top plate temperature value. At the temperature trough, it is also decomposed into an overall section temperature value and a positive gradient temperature; the decomposed overall section temperature value at the temperature trough is the bottom plate temperature value.

[0050] After decomposing the cross-sectional temperature values ​​at the peak and trough of temperature, the daily temperature effect is represented by a vertical positive gradient temperature, a vertical negative gradient temperature, and an overall temperature difference. The *Highway Bridge and Culvert Design Code* refers to the temperature effect caused by annual temperature variations as the overall temperature difference effect, and the temperature effect that creates a nonlinear temperature gradient along the height or width of the structure as the gradient temperature effect. In this paper, the difference between the top plate temperature value at the peak of the daytime temperature fluctuation of the steel box girder cross-section and the bottom plate temperature value at the trough of the nighttime temperature fluctuation of the steel box girder cross-section is the overall temperature difference for one day, denoted as […]. The maximum positive vertical temperature difference between the top and bottom plates is measured using... This indicates that the absolute value of the maximum vertical negative temperature difference between the top and bottom plates in a single day is expressed as... express.

[0051] S3: Determine the daily equivalent temperature stress amplitude based on the absolute value of the overall temperature difference, the absolute value of the maximum positive temperature difference in the vertical direction of the top and bottom plates, and the absolute value of the maximum negative temperature difference in the vertical direction of the top and bottom plates.

[0052] In this embodiment, the difference between the maximum and minimum daily temperature fatigue stress at a specific detail of the bridge structure under the influence of a single day's temperature is defined as the daily temperature stress amplitude. .use , and The daily temperature effect is represented by three components, and the daily temperature stress amplitude also consists of three parts.

[0053] The daily temperature stress amplitude is the difference between the maximum and minimum temperature fatigue stress values ​​at a specific detail of the bridge structure under the influence of a single day's temperature. .use , and The daily temperature stress amplitude, representing the effect of temperature over a day, is also composed of three parts: the effect of the absolute value of the overall temperature difference, and the effect of temperature stress over a day. The resulting daily temperature stress amplitude and positive gradient temperature The daily temperature stress amplitude and negative gradient temperature caused by the action The daily temperature stress amplitude caused by the action. Since the stress generated by temperature action is within the elastic range of the material,... , and The resulting daily temperature stress amplitudes can be linearly superimposed. The superposition of daily temperature stress amplitudes can be expressed by the following formula:

[0054]

[0055] In the formula: For the first Temperature stress amplitude during the day. For the first The effect of uniform temperature The resulting overall temperature difference stress amplitude, For the first Tianzheng gradient temperature effect The resulting daily temperature stress amplitude, For the first Negative temperature gradient effect The resulting daily temperature stress amplitude.

[0056] Step S3 specifically includes:

[0057] S31: Establish a finite element model to analyze and calculate the correspondence between the absolute value of the daily overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive vertical temperature difference of the top and bottom plates and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative vertical temperature difference of the top and bottom plates and the maximum negative temperature difference stress amplitude.

[0058] In this example, the relationship between the absolute value of the overall temperature difference and the amplitude of the overall temperature difference stress is as follows: ,in, The overall temperature difference stress amplitude caused by the absolute value of the overall temperature difference on day i. This is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference. This represents the absolute value of the overall temperature difference.

[0059] The relationship between the maximum vertical positive temperature difference between the top and bottom plates and the maximum positive temperature difference stress amplitude is as follows: ,in, Let be the maximum positive temperature difference stress amplitude caused by the maximum positive temperature difference between the top and bottom plates on day i. It is the ratio of the maximum positive temperature difference stress amplitude to the maximum vertical positive temperature difference between the top and bottom plates. This represents the absolute value of the maximum positive vertical temperature difference between the top and bottom plates.

[0060] The relationship between the absolute value of the maximum vertical negative temperature difference between the top and bottom plates and the amplitude of the maximum negative temperature difference stress is as follows: ,in, Let be the maximum negative temperature difference stress amplitude caused by the maximum vertical negative temperature difference between the top and bottom plates on day i. It is the ratio of the maximum negative temperature difference stress amplitude to the maximum vertical negative temperature difference of the base plate. This represents the absolute value of the maximum negative temperature difference between the top and bottom plates in the vertical direction.

[0061] The specific solution principle is given below: Specifically, the overall temperature difference is analyzed. Assume that on a certain day, the overall temperature difference of the steel box girder cross-section is... The temperature fatigue stress amplitude of a certain detail of the structure under the action of the overall temperature difference is _____. The overall temperature difference of the steel box girder section on the second day was... Under the influence of the overall temperature difference, the temperature fatigue stress amplitude of this detail is Materials expand and contract with temperature changes, but their coefficient of linear expansion remains constant. Therefore, the temperature fatigue stress on a structure is directly proportional to the temperature. The ratio of the daily temperature stress amplitude caused by the overall temperature difference to the overall temperature difference is a constant. Let the ratio of the longitudinal daily temperature stress amplitude caused by the overall temperature difference to the overall temperature difference be denoted as... The ratio of the amplitude of the transverse daily temperature stress caused by the overall temperature difference to the overall temperature difference is: The analytical relationship between the daily temperature stress amplitude caused by the overall temperature difference and the overall temperature difference can be expressed as:

[0062]

[0063] In the formula: This refers to the longitudinal daily temperature stress amplitude caused by the overall temperature difference. This refers to the amplitude of the transverse daily temperature stress caused by the overall temperature difference. This is due to the overall temperature difference. It can be uniformly written as the following formula:

[0064]

[0065] In the formula: The daily temperature stress amplitude caused by the overall temperature difference. It is the ratio of the daily temperature stress amplitude caused by the overall temperature difference to the overall temperature difference.

[0066] Analyze the daily vertical positive temperature gradient. Since the fitted curve of the vertical positive temperature gradient is... . Values ​​and Unrelated Let y represent the temperature of the bottom plate, y be the vertical coordinate, and e be the natural logarithm. In this example, the temperature of the steel box girder bridge is being monitored. The value is -0.94m -1 The value is now confirmed. Daily monitoring of steel box girder bridges. Approximately -0.94m -1 It is only necessary to determine the maximum positive vertical temperature difference between the top and bottom plates on that day.

[0067] like Figure 3 and Figure 4 As shown, assuming the maximum vertical positive temperature difference between the top and bottom plates on a certain day is... The fitted curve of the vertical positive temperature gradient for that day is: The stress value at a certain detail under the action of a vertical positive temperature gradient is Assume the maximum vertical temperature difference between the top and bottom plates on the second day is... The fitted curve of the vertical positive temperature gradient for that day is: The stress value of this detail under the action of a vertical positive temperature gradient is For temperature values ​​at the same height of the beam section, the ratio of the temperature value on the second day to that on the first day is: , is a constant value Due to thermal expansion and contraction of materials, and the constant linear expansion coefficient, the temperature fatigue stress at structural details is directly proportional to the temperature value. Therefore, the ratio of temperature fatigue stress over two days is also a constant. That is, at the same structural detail, the ratio of temperature fatigue stress on the second day to that on the first day is... The ratio of the temperature fatigue stress on the first day to the maximum vertical positive temperature difference between the top and bottom plates is [value missing]. The ratio of the temperature fatigue stress on the second day to the maximum vertical positive temperature difference between the top and bottom plates was [value missing]. The ratio is equal to the ratio on the first day. The fitted curve is... Under the influence of a vertical positive temperature gradient, the ratio of the temperature fatigue stress at a certain detail of the bridge structure to the maximum vertical temperature difference between the top and bottom slabs is a constant. Let the ratio of the longitudinal daily temperature stress amplitude caused by the vertical positive temperature gradient to the maximum vertical temperature difference between the top and bottom slabs be denoted as: The ratio of the amplitude of the transverse daily temperature stress caused by the vertical positive gradient temperature effect to the maximum vertical temperature difference between the top and bottom plates is: The analytical relationship between the daily temperature stress amplitude caused by the vertical positive gradient temperature effect and the maximum vertical temperature difference between the top and bottom plates can be expressed as:

[0068]

[0069] In the formula: This represents the longitudinal daily temperature stress amplitude caused by the vertical positive temperature gradient. This represents the amplitude of the transverse daily temperature stress caused by the vertical positive temperature gradient. For the first The maximum positive vertical temperature difference between the ceiling and floor slabs. The above formula can be uniformly written as the following formula:

[0070]

[0071] Similarly, it can be obtained that when the fitted curve is Under the influence of a vertical negative temperature gradient, the ratio of the temperature fatigue stress at a certain detail of the bridge structure to the absolute value of the minimum vertical negative temperature difference (the maximum absolute value of the negative temperature difference) between the top and bottom plates is also a constant. Let the ratio of the longitudinal daily temperature stress amplitude caused by the vertical negative temperature gradient to the maximum absolute value of the negative temperature difference be denoted as... Let the ratio of the amplitude of the transverse daily temperature stress caused by the vertical negative temperature gradient to the maximum absolute value of the negative temperature difference be denoted as . The analytical relationship between the daily temperature stress amplitude caused by the vertical negative temperature gradient and the maximum absolute value of the vertical negative temperature difference can be expressed as:

[0072]

[0073] In the formula: This represents the longitudinal daily temperature stress amplitude caused by the vertical negative temperature gradient. This represents the amplitude of the transverse daily temperature stress caused by the vertical negative temperature gradient. For the first The maximum absolute value of the vertical negative temperature difference between the ceiling and the floor. The above formula can be uniformly written as the following formula:

[0074]

[0075] S31: Determine the daily equivalent temperature stress amplitude based on the correspondence between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive vertical temperature difference of the top and bottom plates and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative vertical temperature difference of the top and bottom plates and the maximum negative temperature difference stress amplitude.

[0076] In this example, according to the formula: Determine the daily equivalent temperature stress amplitude ;

[0077] in, For the total number of days in the statistics, The overall temperature difference stress amplitude caused by the absolute value of the overall temperature difference on day i. Let be the maximum positive temperature difference stress amplitude caused by the maximum positive temperature difference between the top and bottom plates on day i. Let be the maximum negative temperature difference stress amplitude caused by the maximum vertical negative temperature difference between the top and bottom plates on day i. It is the sum of the overall temperature difference stress amplitude, the maximum negative temperature difference stress amplitude, and the maximum positive temperature difference stress amplitude. , This is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference. It is the ratio of the maximum positive temperature difference stress amplitude to the maximum vertical positive temperature difference between the top and bottom plates. It is the ratio of the maximum negative temperature difference stress amplitude to the maximum vertical negative temperature difference of the base plate.

[0078] S4: Based on SN The curve is used to calculate the temperature fatigue damage of the bridge structure based on the daily equivalent temperature stress amplitude.

[0079] In this embodiment, assessing the damage effect caused by temperature requires establishing the relationship between external load and fatigue damage. The curve reflecting the relationship between fatigue stress amplitude S and fatigue life N is called the SN curve, such as... Figure 5 As shown.

[0080] For the nominal stress spectrum, the corresponding fatigue strength curve is:

[0081]

[0082] In the formula: This represents the actual stress amplitude level. m for SN The slope of the curve; This represents the number of cycles at which fatigue failure occurs. This represents the fatigue limit of constant amplitude. This represents a typical fatigue detail level, corresponding to 2×10. 6 The number of loops. When Greater than hour, m =3. When Less than hour, m =5. This is the fatigue threshold value, when Less than At that time, it was assumed that the structure would not suffer fatigue damage.

[0083] In this example, the daily equivalent temperature stress amplitude is used as the actual stress amplitude level for calculation.

[0084] S5: Based on the absolute value of the overall temperature difference, the maximum positive temperature difference in the vertical direction of the top and bottom plates, and the maximum negative temperature difference in the vertical direction of the top and bottom plates, the temperature fatigue damage of other bridge structures within the set range where the temperature environment differs from the measured bridge temperature environment.

[0085] This scheme obtains the absolute value of the daily overall temperature difference, the maximum positive temperature difference in the top and bottom slabs, and the absolute value of the maximum negative temperature difference in the top and bottom slabs. It then establishes a finite element model to analyze and calculate the correspondence between the absolute value of the daily overall temperature difference and the overall temperature difference stress amplitude, the correspondence between the maximum positive temperature difference in the top and bottom slabs and the maximum positive temperature difference stress amplitude, and the correspondence between the absolute value of the maximum negative temperature difference in the top and bottom slabs and the maximum negative temperature difference stress amplitude, thereby predicting the temperature fatigue damage of other bridge structures.

[0086] On the other hand, the present invention also includes a bridge structure temperature fatigue damage calculation system, comprising: a temperature curve module, a temperature difference determination module, an equivalent temperature stress amplitude determination module, and a temperature fatigue damage determination module.

[0087] The temperature curve module is used to establish daily top and bottom plate temperature curves based on the top and bottom plate temperatures within a set time period; the temperature difference determination module is used to obtain the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom plates, and the absolute value of the maximum negative vertical temperature difference between the top and bottom plates based on the daily top and bottom plate temperature curves within a set time period; the equivalent temperature stress amplitude determination module is used to determine the daily equivalent temperature stress amplitude based on the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the top and bottom plates, and the maximum negative vertical temperature difference between the top and bottom plates; the temperature fatigue damage determination module is used to determine the daily equivalent temperature stress amplitude based on the daily temperature difference and the absolute values ​​of the maximum positive and negative vertical temperature difference between the top and bottom plates; SN The curve is used to calculate the temperature fatigue damage of the bridge structure based on the daily equivalent temperature stress amplitude.

[0088] In summary, this scheme establishes daily roof and floor temperature curves based on the roof and floor temperatures within a set time period; it obtains the absolute value of the overall temperature difference, the maximum positive vertical temperature difference between the roof and floor, and the absolute value of the maximum negative vertical temperature difference between the roof and floor based on these daily temperature curves; and it determines the daily equivalent temperature stress amplitude based on these daily absolute values. SN The curve is used to calculate the temperature fatigue damage of bridge structures based on the daily equivalent temperature stress amplitude. The calculation method is simple and does not require equipment with high computing power, which can improve calculation efficiency and save costs.

[0089] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0090] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method of calculating temperature fatigue damage of a bridge structure, characterized by, The method comprises the following steps: According to the measured top plate temperature and bottom plate temperature in the set time period, the top plate temperature curve and the bottom plate temperature curve of each day are established; According to the top plate temperature curve and the bottom plate temperature curve of each day in the set time period, the absolute value of the overall temperature difference, the maximum positive temperature difference and the absolute value of the maximum negative temperature difference of the top and bottom plates are obtained each day; According to the absolute value of the overall temperature difference, the maximum positive temperature difference and the absolute value of the maximum negative temperature difference of the top and bottom plates each day, the daily equivalent temperature stress amplitude is determined, comprising: The corresponding relationship between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the corresponding relationship between the maximum positive temperature difference and the maximum positive temperature difference stress amplitude, and the corresponding relationship between the absolute value of the maximum negative temperature difference and the maximum negative temperature difference stress amplitude are established by analyzing and calculating the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the maximum positive temperature difference and the maximum positive temperature difference stress amplitude, and the absolute value of the maximum negative temperature difference and the maximum negative temperature difference stress amplitude each day; The daily equivalent temperature stress amplitude is determined according to the corresponding relationship between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the corresponding relationship between the maximum positive temperature difference and the maximum positive temperature difference stress amplitude, and the corresponding relationship between the absolute value of the maximum negative temperature difference and the maximum negative temperature difference stress amplitude. Based on S-N The curve is used to calculate the temperature fatigue damage of the bridge structure according to the daily equivalent temperature stress amplitude. The absolute value of the overall temperature difference each day is the absolute value of the difference between the top plate temperature value when the steel box girder cross-section temperature fluctuation peak value appears in the daytime and the bottom plate temperature value when the steel box girder cross-section temperature fluctuation trough value appears at night, the absolute value of the maximum negative temperature difference of the top and bottom plates is the absolute value of the difference between the wave trough of the top plate temperature curve and the wave trough of the bottom plate temperature curve, and the maximum positive temperature difference of the top and bottom plates is the absolute value of the difference between the wave peak of the top plate temperature curve and the wave peak of the bottom plate temperature curve.

2. The method of claim 1, wherein: According to the absolute value of the overall temperature difference, the maximum positive temperature difference and the absolute value of the maximum negative temperature difference of the top and bottom plates each day, the temperature fatigue damage of other bridge structures within the set range is calculated when the temperature environment and the measured bridge temperature environment differ.

3. The method for calculating temperature fatigue damage of bridge structures as described in claim 1, characterized in that, The corresponding relationship between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude is: wherein, the overall temperature difference stress amplitude caused by the absolute value of the overall temperature difference on the i-th day, is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference, is the absolute value of the overall temperature difference.

4. The method for calculating temperature fatigue damage of bridge structures as described in claim 1, characterized in that, The corresponding relationship between the vertical maximum positive temperature difference of the top and bottom plate and the maximum positive temperature difference stress amplitude is: Wherein, The maximum positive temperature difference stress amplitude caused by the vertical maximum positive temperature difference of the top and bottom plate on the i th day, The ratio of the maximum positive temperature difference stress amplitude to the vertical maximum positive temperature difference of the top and bottom plate, The absolute value of the vertical maximum positive temperature difference of the top and bottom plate.

5. The method of claim 1, wherein, The corresponding relationship between the absolute value of the vertical maximum negative temperature difference of the top and bottom plate and the maximum negative temperature difference stress amplitude is: Wherein, is the maximum negative temperature difference stress amplitude caused by the vertical maximum negative temperature difference of the top and bottom plate on the i th day, is the ratio of the maximum negative temperature difference stress amplitude to the vertical maximum negative temperature difference of the bottom plate, is the absolute value of the vertical maximum negative temperature difference of the top and bottom plate.

6. The method of claim 1, wherein, The daily equivalent temperature stress amplitude is determined according to the corresponding relationship between the absolute value of the overall temperature difference and the overall temperature difference stress amplitude, the corresponding relationship between the maximum positive temperature difference and the maximum positive temperature difference stress amplitude, and the corresponding relationship between the absolute value of the maximum negative temperature difference and the maximum negative temperature difference stress amplitude. The daily equivalent temperature stress amplitude is determined according to the formula: ;​ wherein, is the total number of days for statistics, is the absolute value of the overall temperature difference of the i-th day, is the maximum positive temperature difference stress amplitude caused by the maximum positive temperature difference of the i-th day, is the maximum negative temperature difference stress amplitude caused by the maximum negative temperature difference of the i-th day, is the sum of the overall temperature difference stress amplitude, the maximum negative temperature difference stress amplitude and the maximum positive temperature difference stress amplitude, , is the ratio of the overall temperature difference stress amplitude to the absolute value of the overall temperature difference, is the ratio of the maximum positive temperature difference stress amplitude to the maximum positive temperature difference of the floor, is the ratio of the maximum negative temperature difference stress amplitude to the maximum negative temperature difference of the floor.

7. The method of claim 1, wherein, The top plate temperature and the bottom plate temperature in the set time period are collected; According to the top plate temperature and the bottom plate temperature in the set time period, the top plate temperature function and the bottom plate temperature function of each day are fitted; According to the top plate temperature function and the bottom plate temperature function of each day, the top plate temperature curve and the bottom plate temperature curve of each day are established. It comprises:

8. A system for calculating temperature fatigue damage of a bridge structure, characterized by, A temperature curve module is configured to establish the top plate temperature curve and the bottom plate temperature curve of each day according to the top plate temperature and the bottom plate temperature in the set time period; ​ a temperature difference determination module configured to obtain an absolute value of a daily overall temperature difference, an absolute value of a maximum vertical positive temperature difference between the top slab and the bottom slab, and an absolute value of a maximum vertical negative temperature difference between the top slab and the bottom slab according to the top slab temperature curve and the bottom slab temperature curve of each day in the set time period, the absolute value of the daily overall temperature difference being an absolute value of a difference between a top slab temperature value at a peak value of a daytime steel box girder cross-section temperature fluctuation and a bottom slab temperature value at a trough value of a nighttime steel box girder cross-section temperature fluctuation, the absolute value of the maximum vertical negative temperature difference between the top slab and the bottom slab being an absolute value of a difference between a trough value of the top slab temperature curve and a trough value of the bottom slab temperature curve, and the maximum vertical positive temperature difference between the top slab and the bottom slab being an absolute value of a difference between a peak value of the top slab temperature curve and a peak value of the bottom slab temperature curve; an equivalent temperature stress amplitude determination module configured to determine a daily equivalent temperature stress amplitude according to the absolute value of the daily overall temperature difference, the absolute value of the maximum vertical positive temperature difference between the top slab and the bottom slab, and the absolute value of the maximum vertical negative temperature difference between the top slab and the bottom slab, including: establishing a finite element model to analyze and calculate a corresponding relationship between the absolute value of the daily overall temperature difference and an overall temperature difference stress amplitude, a corresponding relationship between the maximum vertical positive temperature difference between the top slab and the bottom slab and a maximum positive temperature difference stress amplitude, and a corresponding relationship between the absolute value of the maximum vertical negative temperature difference between the top slab and the bottom slab and a maximum negative temperature difference stress amplitude; determining the daily equivalent temperature stress amplitude according to the corresponding relationship between the absolute value of the daily overall temperature difference and the overall temperature difference stress amplitude, the corresponding relationship between the maximum vertical positive temperature difference between the top slab and the bottom slab and the maximum positive temperature difference stress amplitude, and the corresponding relationship between the absolute value of the maximum vertical negative temperature difference between the top slab and the bottom slab and the maximum negative temperature difference stress amplitude; a temperature fatigue damage determining module for determining a temperature fatigue damage of the bridge structure based on S-N a curve for calculating the temperature fatigue damage of the bridge structure as a function of the daily equivalent temperature stress amplitude.

Images