CN110820520B - Method and device for calculating fatigue life of suspension cable of suspension bridge - Google Patents
Method and device for calculating fatigue life of suspension cable of suspension bridge Download PDFInfo
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- CN110820520B CN110820520B CN201911077417.7A CN201911077417A CN110820520B CN 110820520 B CN110820520 B CN 110820520B CN 201911077417 A CN201911077417 A CN 201911077417A CN 110820520 B CN110820520 B CN 110820520B
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D11/00—Suspension or cable-stayed bridges
- E01D11/02—Suspension bridges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/16—Suspension cables; Cable clamps for suspension cables ; Pre- or post-stressed cables
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Abstract
The embodiment of the invention provides a method and a device for calculating the fatigue life of a suspension cable of a suspension bridge, wherein the method comprises the steps of collecting vehicle load data of the suspension bridge for preset days to reconstruct the daily vehicle load current of the suspension bridge; establishing a three-dimensional finite element model of the suspension bridge, calculating the internal force of the suspension cable under the action of constant load based on the three-dimensional finite element model, and acquiring a continuous influence surface of the internal force of the suspension cable; loading the reconstructed vehicle load current to a continuous influence surface of the internal force of the sling every day to obtain an internal force time-course curve of the sling every day, wherein the internal force time-course curve is generated by the vehicle load; and obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days. The embodiment of the invention avoids the calculation deviation caused by the randomness of short-term vehicle load data.
Description
Technical Field
The invention relates to the technical field of bridge engineering, in particular to a method and a device for calculating the fatigue life of a suspension cable of a suspension bridge.
Background
The sling is a key stressed component of the suspension bridge, and the stress state of the sling directly relates to the overall safety state and the use performance of the suspension bridge. However, as the number of heavy-duty vehicles on roads is increasing, the level of vehicle load borne by the bridge structure is also increasing, so that the fatigue problem of the bridge structure is becoming more and more prominent. The detection results of the solid bridge at home and abroad show that the phenomenon of fatigue fracture of steel wires occurs in certain suspension bridge slings even if the designed service life is not reached, so a scientific and reasonable calculation and analysis method for the fatigue life of the suspension bridge slings is urgently needed, and a basis is provided for management and maintenance of a large-span suspension bridge in the operation period.
The stress time course of the sling under the action of vehicle load is the basis for calculating the fatigue life of the sling, however, a reliable and effective method for acquiring the stress time course of the sling under an operating state is not available. On one hand, the existing sensing technology is difficult to realize long-term continuous real-time monitoring of the internal force of the sling, and on the other hand, the existing calculation method mostly adopts the vehicle load in the specification to calculate the internal force of the sling of the suspension bridge, which is different from the vehicle load born by the suspension bridge in the operation period necessarily, and the calculation error is larger.
At present, most of large-span suspension bridges in China are provided with structural health monitoring systems, dynamic weighing systems are often arranged in the systems, the dynamic weighing systems can accurately monitor vehicle load data at bridge sites of the suspension bridges, the data truly record vehicle load conditions of the suspension bridges, and basis can be provided for accurately calculating fatigue life of suspension bridges. However, at present, the fatigue life of the suspension bridge sling is not calculated by using data obtained by a dynamic weighing system at home and abroad.
Disclosure of Invention
Embodiments of the present invention provide a method and an apparatus for calculating fatigue life of a suspension cable of a suspension bridge, which overcome the above problems or at least partially solve the above problems.
In a first aspect, an embodiment of the present invention provides a method for calculating a fatigue life of a suspension cable of a suspension bridge, including:
collecting vehicle load data of the suspension bridge in preset days to reconstruct the daily vehicle load flow of the suspension bridge;
establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the suspension cable under the action of constant load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the suspension cable;
loading the reconstructed vehicle load current to a continuous influence surface of the internal force of the sling every day to obtain an internal force time-course curve of the sling every day, wherein the internal force time-course curve is generated by the vehicle load;
and obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days.
Preferably, the obtaining of the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load action specifically comprises:
obtaining a stress time-course curve of each day according to the internal force time-course curve of each day of the sling and the internal force under the action of the constant load, and extracting a plurality of stress cycles from the stress time-course curve of each day;
calculating the fatigue damage of the sling every day according to the cycle number, the stress range and the average stress of all stress cycles;
preferably, the calculating the fatigue damage of the sling per day according to the cycle number, the stress range and the average stress of all stress cycles specifically comprises:
for any stress cycle, correcting the stress range of the stress cycle according to the average stress of the stress cycle and the ultimate tensile strength of the steel wire used by the sling to obtain the corrected stress range;
obtaining the fatigue life cycle number of the sling steel wire corresponding to the corrected stress range according to the fatigue strength curve of the sling steel wire;
and obtaining the daily fatigue damage of the sling according to the cycle times of all stress cycles and the corresponding cycle times of the fatigue life.
Preferably, the determining the fatigue life according to the fatigue damage of the sling per day in the preset number of days specifically comprises:
calculating the average value of fatigue damage of each day in preset days as daily average fatigue damage D;
according to the formula:
the fatigue life Y of the sling was obtained.
The method is characterized by collecting vehicle load data of the suspension bridge with preset days to reconstruct the vehicle load current of the suspension bridge every day, and specifically comprises the following steps:
the dynamic weighing system installed at the end of the bridge is adopted to record vehicle load data, and the vehicle load data comprises: one or more of the data of the gross weight of the vehicle, the axle weight, the vehicle speed, the wheel base, the arrival time, the number of lanes and axles;
calculating the position of each vehicle relative to the suspension bridge at 0 min and 0 s every day by using the speed and the arrival time of each vehicle;
each vehicle is equivalent to a concentrated force group, the quantity of concentrated forces in each concentrated force group is the quantity of axles, the position interval of adjacent concentrated forces in each concentrated force group is equal to the axle distance, and the magnitude of the concentrated forces is equal to the axle weight of each axle;
taking the center line position of a lane where each vehicle is located as the loading position of the equivalently obtained concentrated force group on the suspension bridge;
and arranging the equivalently obtained concentrated force groups according to the position of each vehicle at 0 minute and 0 second every day, so as to form the load carrying flow of each vehicle every day.
Preferably, the establishing a three-dimensional space finite element model of the suspension bridge specifically includes:
the main cable and the sling of the suspension bridge adopt a rod unit, the bridge tower adopts a beam unit, and the bridge deck structure adopts a shell unit and a beam unit so as to obtain a three-dimensional space finite element model of the suspension bridge.
Preferably, the continuous influence surface for acquiring the internal force of the sling is specifically as follows:
and loading unit concentrated force on the three-dimensional space finite element model to obtain a discrete influence surface of the internal force of the sling, and performing linear interpolation on the obtained discrete influence surface to obtain the continuous influence surface.
In a second aspect, an embodiment of the present invention provides a device for calculating fatigue life of a suspension cable of a suspension bridge, including:
the load reconstruction module is used for acquiring vehicle load data of the suspension bridge in preset days to reconstruct the vehicle load flow of the suspension bridge every day;
the finite element module is used for establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the sling under the action of the constant load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the sling;
the internal force time course calculation module is used for loading the reconstructed vehicle load current each day to a continuous influence surface of internal force of the sling, and obtaining an internal force time course curve generated by the vehicle load of the sling each day;
and the fatigue life calculation module is used for obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days.
In a third aspect, an embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the method provided in the first aspect when executing the program.
In a fourth aspect, an embodiment of the present invention provides a non-transitory computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of the method as provided in the first aspect.
According to the method and the device for calculating the fatigue life of the suspension bridge sling, provided by the embodiment of the invention, firstly, the load information of a vehicle at the bridge site of the suspension bridge contained in the dynamic weighing system is fully utilized, the calculation result can truly reflect the actual stress state of the suspension bridge sling and is in line with the actual situation, the dynamic weighing subsystem in the conventional suspension bridge health monitoring system is directly utilized, new software and hardware such as a sensor and a collecting instrument are not required to be additionally input, and the cost performance is higher.
Secondly, aiming at the characteristics that the common bridge deck of the suspension bridge has larger transverse width and comprises a plurality of lanes, and the influence degree of each lane on the internal force of the suspension cable is different, the embodiment of the invention provides a method for establishing a three-dimensional space finite element model of the suspension bridge, so that the transverse distribution of vehicle load when the bridge deck passes can be really considered, and the calculation result is more accurate.
And thirdly, the embodiment of the invention provides a thought for calculating the fatigue life of the sling by using long-term vehicle load data, the data acquisition time of the dynamic weighing system can be determined according to the actual condition, the fatigue life of the sling is predicted according to the average fatigue damage in the data acquisition time, and the calculation deviation caused by the randomness of short-term vehicle load data is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic flow chart of a method for calculating fatigue life of a suspension cable of a suspension bridge according to an embodiment of the present invention;
FIG. 2 is a schematic illustration of a reconfigured vehicle load flow in accordance with an embodiment of the present invention;
FIG. 3 is a graph illustrating the stress time course of a sling 2018 at 4 months and 10 days according to an embodiment of the present invention;
FIG. 4 is a graph illustrating a daily fatigue damage curve according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a device for calculating fatigue life of a suspension cable of a suspension bridge according to an embodiment of the present invention;
fig. 6 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic flow chart of a method for calculating fatigue life of a suspension cable of a suspension bridge according to an embodiment of the present invention, as shown in fig. 1, including:
s101, vehicle load data of the suspension bridge in preset days are collected to reconstruct the daily vehicle load flow of the suspension bridge.
Specifically, the embodiment of the invention adopts a dynamic weighing system installed at the end of the bridge to record vehicle load data, and the vehicle load data comprises the following components: one or more of the data of the gross weight of the vehicle, the axle weight, the vehicle speed, the wheel base, the arrival time, the number of lanes and axles.
Calculating the position of each vehicle relative to the suspension bridge at 0 min and 0 s every day by using the vehicle speed and the arrival time of each vehicle, and equating each vehicle to be a concentrated force group, wherein the quantity of concentrated forces in each concentrated force group is the quantity of axles, the position interval of adjacent concentrated forces in each concentrated force group is equal to the axle distance, and the magnitude of the concentrated force is equal to the axle weight of each axle;
taking the center line position of a lane where each vehicle is located as the loading position of the equivalently obtained concentrated force group on the suspension bridge; and arranging the equivalently obtained concentrated force groups according to the position of each vehicle at 0 minute and 0 second every day, so as to form the load carrying flow of each vehicle every day.
S102, establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the suspension cable under the action of the dead load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the suspension cable.
Specifically, a main cable and a sling of the suspension bridge adopt a rod unit, a bridge tower adopts a beam unit, and a bridge deck structure adopts a shell unit and a beam unit so as to obtain a three-dimensional space finite element model of the suspension bridge.
S103, loading the reconstructed daily vehicle load current to a continuous influence surface of the internal force of the sling, and obtaining an internal force time-course curve of the sling generated by the vehicle load every day.
Specifically, the reconstructed load-carrying current of the vehicle every day is loaded on a continuous influence surface of the internal force of the sling, the total calculation time is 0 minute 0 second to 23 minutes 59 seconds every day, the calculation time step is 0.2 second, and an internal force time course curve generated by the load of the vehicle every day of the sling is obtained;
and S104, obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days.
Specifically, a stress time course curve of each day is obtained according to the internal force time course curve of each day of the sling and the internal force under the action of the constant load, and a plurality of stress cycles are extracted from the stress time course curve of each day; and calculating the daily fatigue damage of the sling according to the cycle number, the stress range and the average stress of all stress cycles.
Firstly, the embodiment of the invention fully utilizes the load information of the suspension bridge site vehicle contained in the dynamic weighing system, the calculation result can truly reflect the actual stress state of the suspension bridge sling, and the invention accords with the actual situation.
Secondly, aiming at the characteristics that the common bridge deck of the suspension bridge has larger transverse width and comprises a plurality of lanes, and the influence degree of each lane on the internal force of the suspension cable is different, the embodiment of the invention provides a method for establishing a three-dimensional space finite element model of the suspension bridge, so that the transverse distribution of vehicle load when the bridge deck passes can be really considered, and the calculation result is more accurate.
And thirdly, the embodiment of the invention provides a thought for calculating the fatigue life of the sling by using long-term vehicle load data, the data acquisition time of the dynamic weighing system can be determined according to the actual condition, the fatigue life of the sling is predicted according to the average fatigue damage in the data acquisition time, and the calculation deviation caused by the randomness of short-term vehicle load data is avoided.
On the basis of the above embodiments, as an alternative embodiment, the stress time course curve σ is specifically calculated by the following formula:
wherein, TvShows the time course curve of the internal force of the sling under the action of the vehicle load, TdThe internal force of the sling under the action of constant load is shown, DAF is a power amplification coefficient, and a is the cross-sectional area of the sling.
On the basis of the above embodiments, as an optional embodiment, a plurality of stress cycles are extracted from a daily stress time course curve, specifically: processing the stress time-course curve sigma of the sling per day by adopting a rain flow counting method, and extracting k stress cycles, wherein the cycle number, the stress range and the average stress of each stress cycle are respectively nj、sjAnd σj(j ═ 1,2, …, k, k are positive integers).
On the basis of the above embodiments, as an alternative embodiment, the calculating the daily fatigue damage of the sling according to the cycle number, the stress range and the average stress of all stress cycles includes:
and for any stress cycle, correcting the stress range of the stress cycle according to the average stress of the stress cycle and the ultimate tensile strength of the steel wire used by the sling to obtain the corrected stress range.
Specifically, the stress range s for each stress cycle is determined using the Goodman equationjCorrecting to obtain corrected stress range smjIs of the formula
In the formula sigmauThe ultimate tensile strength of the steel wire used in the sling.
Obtaining a corrected stress range s according to the fatigue strength curve of the sling wiremjFatigue life cycle times of corresponding sling wires.
Specifically, the fatigue life cycle number of the suspension wire corresponding to the corrected stress range is
In the formula, A is a fatigue strength coefficient, and M is a slope coefficient of a fatigue strength curve.
On the basis of the above embodiments, as an alternative embodiment, the daily fatigue damage of the sling is obtained according to the cycle times of all stress cycles and the corresponding fatigue life cycle times.
The fatigue damage at day i was:
the fatigue life is determined according to the daily fatigue damage of the sling in the preset days, and the method specifically comprises the following steps:
calculating the average value of fatigue damage of each day in preset days as the daily average fatigue damage D, wherein the formula is
According to the formula:
the fatigue life Y of the sling was obtained.
Next, a method for calculating the fatigue life of a suspension cable of a suspension bridge according to an embodiment of the present invention will be described with reference to a specific example.
The dynamic weighing system is arranged at the intersection position of the suspension bridge deck and a bridge tower, the vibration amplitude of the deck is small, the influence on data acquisition is small, and the dynamic weighing system can acquire vehicle load data of 4 lanes in the two directions of the deck.
The data collected by the dynamic weighing system in 4 months in 2018 are selected, the data collection time is 30 days (l is 30 days), it should be noted that the arrival time referred by the invention is the time when the vehicle arrives at the bridge deck position where the dynamic weighing system is located, and the data such as the axle weight, the axle distance, the axle number and the like are also recorded. According to the speed and the arrival time of each vehicle, the position of each vehicle at 0 minute and 0 second in the day can be calculated, each vehicle is arranged according to the sequence of the positions to form a reconstructed vehicle load flow, and the following simplifying method is adopted for conveniently calculating the internal force time course of the sling:
(1) the vehicle is considered to keep constant speed in the process of running on the bridge floor, overtaking is automatically carried out when the vehicle appears on the front side, and the vehicle returns to the original lane to continue running after overtaking;
(2) each vehicle is equivalent to a group of concentrated force, the concentrated force is equal to the axle weight of each vehicle, and the distance between the concentrated forces is equal to the axle distance of each vehicle;
(3) the central line position of the lane where each vehicle is located is the action position of the concentrated force.
FIG. 2 is a schematic illustration of a reconfigured vehicle load flow in accordance with an embodiment of the present invention. The vertical downward arrows in fig. 2 indicate the concentrated force, and all the arrows connected by one horizontal line are called a concentrated force group (also called a group of concentrated forces).
Loading the reconstructed vehicle load current shown in FIG. 2 to a sling internal force continuous influence surface, wherein the total calculation time is 0 min 0 s to 23 min 59 s every day, the calculation time step is 0.2s, and the internal force time course T generated by the vehicle load of the sling every day is obtainedvOn the basis, calculating the stress time course curve sigma of the sling every day, and the formula is
Wherein DAF is the power amplification factor, a is the cross-sectional area of the sling, and FIG. 3 is a schematic diagram of the stress time course curve of a sling 2018, 4 months and 10 days according to an embodiment of the present invention.
Further, the stress time course curve of one day in fig. 3 is processed by a rain flow counting method, and a stress cycle is extracted. The stress range is corrected by adopting a Goodman formula which is
Get into consideration the mean stress σjCorrected stress range smjσ in the formulauThe ultimate tensile strength of the steel wire used by the sling can be determined according to the strength grade of the steel wire actually selected by the sling of the suspension bridge, and the sigma of the steel wire of the sling in the embodiment of the inventionuIs 1670 MPa. Further, the daily fatigue damage D of the sling was calculated using a linear damage accumulation formula and the fatigue strength curve of the sling wireiThe calculation formula is
A in the formula is a fatigue strength coefficient, M is a slope coefficient of a fatigue strength curve, and the fatigue strength coefficient can be determined according to a fatigue test of the sling steel wire.
Calculating the fatigue damage D of the midspan sling in 2018, 4 and 30 daysi(i is 1,2, …,30), the results are shown in fig. 4, fig. 4 is a graph illustrating the daily fatigue damage curve of the embodiment of the present invention, and the sling in this period of time is calculated according to the results of fig. 4
According to the formula
And calculating the fatigue life years of the sling in the midspan. As can be seen from the detailed description in the above example, as shown in fig. 4, the vehicle load flow does not change regularly, and the final result has a large error if the conventional fatigue life calculation method is adopted. The invention fully considers the actual vehicle load condition of the suspension bridge and comprehensively considers the fatigue strength characteristic of the suspension cable, and can reasonably calculate the fatigue life of the suspension cable.
Fig. 5 is a schematic structural diagram of a device for calculating fatigue life of a suspension bridge sling according to an embodiment of the present invention, and as shown in fig. 5, the device for calculating fatigue life of a suspension bridge sling includes: a load reconstruction module 501, a finite element module 502, an internal force time course calculation module 503 and a fatigue life calculation module 504, wherein:
the load reconstruction module 501 is used for acquiring vehicle load data of the suspension bridge in preset days to reconstruct the vehicle load flow of the suspension bridge every day;
the finite element module 502 is used for establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the suspension cable under the action of a constant load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the suspension cable;
the internal force time course calculation module 503 is configured to load the reconstructed vehicle load current each day onto a continuous influence surface of the internal force of the sling, so as to obtain an internal force time course curve generated by the vehicle load of the sling each day;
and the fatigue life calculation module 504 is configured to obtain daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load, and determine the fatigue life according to the daily fatigue damage of the sling in the preset number of days.
The device for calculating the fatigue life of a suspension cable of a suspension bridge according to the embodiments of the present invention specifically executes the flow of the method for calculating the fatigue life of a suspension cable of a suspension bridge according to the embodiments of the present invention, and please refer to the contents of the method for calculating the fatigue life of a suspension cable of a suspension bridge in detail, which are not described herein again. According to the calculating device for the fatigue life of the suspension bridge sling, firstly, the load information of a vehicle at the bridge site of the suspension bridge contained in the dynamic weighing system is fully utilized, the calculation result can truly reflect the actual stress state of the suspension bridge sling and accords with the actual situation, the dynamic weighing subsystem in the existing suspension bridge health monitoring system is directly utilized, new sensors, acquisition instruments and other software and hardware are not required to be additionally input, and the calculating device has high cost performance.
Secondly, aiming at the characteristics that the common bridge deck of the suspension bridge has larger transverse width and comprises a plurality of lanes, and the influence degree of each lane on the internal force of the suspension cable is different, the embodiment of the invention provides a method for establishing a three-dimensional space finite element model of the suspension bridge, so that the transverse distribution of vehicle load when the bridge deck passes can be really considered, and the calculation result is more accurate.
And thirdly, the embodiment of the invention provides a thought for calculating the fatigue life of the sling by using long-term vehicle load data, the data acquisition time of the dynamic weighing system can be determined according to the actual condition, the fatigue life of the sling is predicted according to the average fatigue damage in the data acquisition time, and the calculation deviation caused by the randomness of short-term vehicle load data is avoided.
Fig. 6 is a schematic entity structure diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 6, the electronic device may include: a processor (processor)610, a communication Interface (Communications Interface)620, a memory (memory)630 and a communication bus 640, wherein the processor 610, the communication Interface 620 and the memory 630 communicate with each other via the communication bus 640. The processor 610 may call a computer program stored on the memory 630 and executable on the processor 610 to perform the method for calculating the fatigue life of the suspension bridge sling, which includes: collecting vehicle load data of the suspension bridge in preset days to reconstruct the daily vehicle load flow of the suspension bridge; establishing a three-dimensional finite element model of the suspension bridge, obtaining a continuous influence surface of the internal force of the suspension cable from the three-dimensional finite element model, and calculating the internal force of the suspension cable under the action of constant load; loading the reconstructed vehicle load current to a continuous influence surface of the internal force of the sling every day to obtain an internal force time-course curve of the sling every day, wherein the internal force time-course curve is generated by the vehicle load; and obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days.
In addition, the logic instructions in the memory 630 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solutions of the embodiments of the present invention may be essentially implemented or make a contribution to the prior art, or may be implemented in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
An embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program is implemented to perform the method for calculating the fatigue life of a suspension cable of a suspension bridge, provided by the foregoing embodiments, when executed by a processor, for example, the method includes: collecting vehicle load data of the suspension bridge in preset days to reconstruct the daily vehicle load flow of the suspension bridge; establishing a three-dimensional finite element model of the suspension bridge, obtaining a continuous influence surface of the internal force of the suspension cable from the three-dimensional finite element model, and calculating the internal force of the suspension cable under the action of constant load; loading the reconstructed vehicle load current to a continuous influence surface of the internal force of the sling every day to obtain an internal force time-course curve of the sling every day, wherein the internal force time-course curve is generated by the vehicle load; and obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A method for calculating fatigue life of a suspension cable of a suspension bridge is characterized by comprising the following steps:
collecting vehicle load data of the suspension bridge in preset days to reconstruct the daily vehicle load flow of the suspension bridge;
establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the suspension cable under the action of constant load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the suspension cable;
loading the reconstructed vehicle load current to a continuous influence surface of the internal force of the sling every day to obtain an internal force time-course curve of the sling every day, wherein the internal force time-course curve is generated by the vehicle load;
obtaining the fatigue damage of the sling every day according to the internal force time-course curve and the internal force under the action of the constant load, and determining the fatigue life according to the fatigue damage of the sling every day in the preset number of days;
the method is characterized in that the fatigue damage of the sling every day is obtained according to the internal force time-course curve and the internal force under the constant load action, and specifically comprises the following steps:
obtaining a stress time course curve of the sling rope per day according to the internal force time course curve of the sling rope per day and the internal force under the action of the constant load, and extracting a plurality of stress cycles from the stress time course curve per day;
calculating the fatigue damage of the sling every day according to the cycle times, the stress range and the average stress corresponding to all stress cycles;
calculating the fatigue damage of the sling every day according to the cycle number, the stress range and the average stress of all stress cycles, specifically:
for any stress cycle, correcting the stress range of the stress cycle according to the average stress of the stress cycle and the ultimate tensile strength of the steel wire used by the sling to obtain the corrected stress range;
obtaining the fatigue life cycle number of the sling steel wire corresponding to the corrected stress range according to the fatigue strength curve of the sling steel wire;
and obtaining the daily fatigue damage of the sling according to the cycle times of all stress cycles and the corresponding cycle times of the fatigue life.
2. The method for calculating the fatigue life of the suspension cable of the suspension bridge according to claim 1, wherein the fatigue life is determined according to the daily fatigue damage of the suspension cable in the preset number of days, and specifically comprises the following steps:
calculating the average value of fatigue damage of each day in preset days as daily average fatigue damage D;
according to the formula:
the fatigue life Y of the sling was obtained.
3. The method for calculating the fatigue life of the suspension bridge sling according to claim 1, wherein the vehicle load data of the suspension bridge of preset days are collected to reconstruct the vehicle load flow of the suspension bridge every day, and specifically the method comprises the following steps:
the dynamic weighing system installed at the end of the bridge is adopted to record vehicle load data, and the vehicle load data comprises: one or more of the data of the gross weight of the vehicle, the axle weight, the vehicle speed, the wheel base, the arrival time, the number of lanes and axles;
calculating the position of each vehicle relative to the suspension bridge at 0 min and 0 s every day by using the speed and the arrival time of each vehicle;
each vehicle is equivalent to a concentrated force group, the quantity of concentrated forces in each concentrated force group is the quantity of axles, the position interval of adjacent concentrated forces in each concentrated force group is equal to the axle distance, and the magnitude of the concentrated forces is equal to the axle weight of each axle;
taking the center line position of a lane where each vehicle is located as the loading position of the equivalently obtained concentrated force group on the suspension bridge;
and arranging the equivalently obtained concentrated force groups according to the position of each vehicle at 0 minute and 0 second every day, so as to form the load carrying flow of each vehicle every day.
4. The method for calculating the fatigue life of the suspension cable of the suspension bridge as claimed in claim 1, wherein the establishing of the three-dimensional space finite element model of the suspension bridge is specifically as follows:
the main cable and the sling of the suspension bridge adopt a rod unit, the bridge tower adopts a beam unit, and the bridge deck structure adopts a shell unit and a beam unit so as to obtain a three-dimensional space finite element model of the suspension bridge.
5. The method for calculating the fatigue life of the suspension cable of the suspension bridge according to claim 1, wherein the obtaining of the continuous influence surface of the internal force of the suspension cable is specifically as follows:
and loading unit concentrated force on the three-dimensional space finite element model to obtain a discrete influence surface of the internal force of the sling, and performing linear interpolation on the obtained discrete influence surface to obtain the continuous influence surface.
6. A device for calculating fatigue life of a suspension cable of a suspension bridge, comprising:
the load reconstruction module is used for acquiring vehicle load data of the suspension bridge in preset days to reconstruct the vehicle load flow of the suspension bridge every day;
the finite element module is used for establishing a three-dimensional space finite element model of the suspension bridge, calculating the internal force of the sling under the action of the constant load based on the three-dimensional space finite element model, and acquiring a continuous influence surface of the internal force of the sling;
the internal force time course calculation module is used for loading the reconstructed vehicle load current each day to a continuous influence surface of internal force of the sling, and obtaining an internal force time course curve generated by the vehicle load of the sling each day;
the fatigue life calculation module is used for obtaining the daily fatigue damage of the sling according to the internal force time-course curve and the internal force under the constant load effect, and determining the fatigue life according to the daily fatigue damage of the sling in the preset days;
the method is characterized in that the fatigue damage of the sling every day is obtained according to the internal force time-course curve and the internal force under the constant load action, and specifically comprises the following steps:
obtaining a stress time course curve of the sling rope per day according to the internal force time course curve of the sling rope per day and the internal force under the action of the constant load, and extracting a plurality of stress cycles from the stress time course curve per day;
calculating the fatigue damage of the sling every day according to the cycle times, the stress range and the average stress corresponding to all stress cycles;
calculating the fatigue damage of the sling every day according to the cycle number, the stress range and the average stress of all stress cycles, specifically:
for any stress cycle, correcting the stress range of the stress cycle according to the average stress of the stress cycle and the ultimate tensile strength of the steel wire used by the sling to obtain the corrected stress range;
obtaining the fatigue life cycle number of the sling steel wire corresponding to the corrected stress range according to the fatigue strength curve of the sling steel wire;
and obtaining the daily fatigue damage of the sling according to the cycle times of all stress cycles and the corresponding cycle times of the fatigue life.
7. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program performs the steps of the method of calculating fatigue life of a suspension bridge sling according to any one of claims 1 to 5.
8. A non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method of calculating fatigue life of a suspension bridge sling according to any one of claims 1 to 5.
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