CN112115540B - Maritime work support structure fatigue analysis method and system fusing measured data - Google Patents
Maritime work support structure fatigue analysis method and system fusing measured data Download PDFInfo
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Abstract
The application relates to a maritime work support structure fatigue analysis method and system fusing measured data, relating to the technical field of maritime work platforms, wherein the method comprises the following steps: obtaining a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values; randomly combining each Poisson ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value to calculate and obtain each corresponding theoretical structural stress; selecting a time period, and when the total error of the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is minimum, determining a corresponding Poisson ratio threshold sub-value, an elastic modulus threshold sub-value and a shear modulus threshold sub-value; and calculating to obtain the structural stress distribution condition, and performing structural fatigue analysis by combining finite element numerical calculation. According to the method and the device, the experience parameters are subjected to split simulation, so that the experience parameters are optimized, a data basis is provided for the reliability of fatigue analysis, and the fatigue analysis of the maritime work support structure is helped.
Description
Technical Field
The invention relates to the technical field of marine engineering platforms, in particular to a marine engineering support structure fatigue analysis method and system fusing measured data.
Background
The maritime work platform is far away from the land for a long time, has the characteristic of island operation, can cause serious social influence due to improper fault treatment, has a service cycle of about dozens of years, is expensive in offshore maintenance cost, and seriously influences the operation economy of the maritime work platform.
Fatigue failure is one of the main failure modes of the marine support structure, so that the fatigue state of the marine support structure can be accurately diagnosed, and the method has great significance for the structural optimization design and safety analysis of the marine support structure.
The fatigue phenomenon of the marine supporting structure is influenced by a large number of uncertain factors, and the traditional diagnosis method is to carry out fatigue accumulated damage analysis, namely, all node stresses of the marine supporting structure are calculated according to an elastic mechanics equation and finite element analysis, interpolation calculation is carried out on a high stress area according to a material fatigue S-N curve, and the fatigue life of the structure body is predicted. Therefore, the key to the fatigue diagnosis of the marine support structure is to establish a high-precision stress distribution of the marine support structure. At present, the traditional fatigue diagnosis method for the marine supporting structure is still based on traditional experience to carry out single model analysis, and according to a real-time stress measurement mode, the arrangement number of sensors is limited, the accuracy of the sensors and the accuracy of the sensors are still limited, and the fatigue analysis requirement of the marine supporting structure which is suitable for the complex marine environment is difficult to meet.
Therefore, in order to meet the use requirements at the present stage, a new technical scheme for fatigue analysis of the maritime work support structure is provided.
Disclosure of Invention
The embodiment of the application provides a maritime work support structure fatigue analysis method and system fusing measured data, and the empirical parameters are subjected to split simulation, so that the empirical parameters are optimized, a data basis is provided for the reliability of fatigue analysis, and help is provided for maritime work support structure fatigue analysis.
In a first aspect, a maritime work support structure fatigue analysis method fused with measured data is provided, the method comprising the following steps:
segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
randomly combining each Poisson ratio threshold sub-value, each elasticity modulus threshold sub-value and each shear modulus threshold sub-value, and obtaining corresponding theoretical structural stress according to a preset stress distribution mechanism model by combining the support boundary stress and the support boundary displacement obtained by monitoring;
selecting a time period, and when the total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is minimum, combining the Poisson ratio threshold sub-value, the elastic modulus threshold sub-value and the shear modulus threshold sub-value corresponding to the theoretical structural stress into an optimal empirical parameter combination;
and calculating to obtain the structural stress distribution condition through a stress distribution mechanism model according to the optimal empirical parameter combination, the measured structural stress and the supporting boundary stress, and further performing structural fatigue analysis by combining finite element numerical calculation according to the structural stress distribution condition.
Specifically, the obtaining of a plurality of poisson ratio threshold value sub-ranges, elastic modulus sub-threshold value ranges and shear modulus threshold value sub-ranges for a preset poisson ratio threshold value range, elastic modulus threshold value range and shear modulus threshold value range specifically includes the following steps:
selecting the number of empirical parameters, and respectively carrying out step-by-step equal difference splitting on a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range according to the number of the empirical parameters to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values.
In particular, the poisson's ratio of the marine support structure is denoted as mu, and the threshold range of poisson's ratio is [ mu ] a ，μ b 】；
The elastic modulus of the marine supporting structure is recorded as E, and the threshold range of the elastic modulus is [ E ] a ，E b 】；
The shear modulus of the marine supporting structure is recorded as G, and the threshold range of the shear modulus is [ G ] a ，G b 】；
Selecting the number of empirical parameters as n +1, and respectively carrying out step type equal difference splitting on the Poisson ratio threshold range, the elastic modulus threshold range and the shear modulus threshold range according to the number of the empirical parameters;
a plurality of said Poisson ratio threshold sub-values are respectively mu a ，
A plurality of threshold values of the elastic modulus are respectively E a ，
A plurality of said shear modulus threshold sub-values are each G a ，
The Poisson ratio threshold sub-value, the modulus of elasticity threshold sub-value and the shear modulus threshold sub-value are arbitrarily combined, each empirical parameter has (n + 1) forms, and (n + 1) forms are total 3 And (4) combining the modes.
Further, before the segmentation processing is performed on the preset poisson ratio threshold range, the elastic modulus threshold range and the shear modulus threshold range, the method further includes the following steps:
and monitoring the measurement structure stress, the supporting boundary stress and the supporting boundary displacement of each monitoring point of the marine engineering supporting structure in real time.
Specifically, the measured structural stress and the stress of all the monitoring pointsThe calculation formula of the total error of the theoretical structure stress is as follows:
the calculation formula of the total error of the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is as follows:
wherein the content of the first and second substances,
t a ～t b for a corresponding time period, f (p) 1 T) the measured structural stress at the corresponding point in time for the first monitoring point, f (p) 2 T) is the measured structural stress at the corresponding time point of the second monitoring point, f (p) m T) is the measured structural stress of the mth monitoring point at the corresponding time point;
f'(p 1 t) is the theoretical structural stress at the first monitoring point at the corresponding point in time, f' (p) 2 T) is the theoretical structural stress at the corresponding time point, f' (p), of the second monitoring point m And t) is the theoretical structural stress of the mth monitoring point at the corresponding time point.
Specifically, the stress of the measurement structure corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset first stress sensor, the stress of the supporting boundary corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset second stress sensor, and the displacement of the supporting boundary corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset displacement sensor.
Specifically, the supporting boundary stress includes: f. of x (t)、f y (t) and f z (t)；
F is x (t) measuring structural stress of the monitoring point at a corresponding time point in the x direction of a preset three-dimensional coordinate system;
f is y (t) measuring structural stress of the monitoring point at a corresponding time point in the y direction of a preset three-dimensional coordinate system;
f is z (t) is the monitorAnd measuring structural stress of the measuring points in the z direction of a preset stereo coordinate system at corresponding time points.
Specifically, the supporting boundary displacement includes: u (t), v (t), w (t);
u (t) is the support boundary displacement of the monitoring point at the corresponding time point in the x direction of a preset stereo coordinate system;
v (t) is the support boundary displacement of the monitoring point in the y direction of a preset stereo coordinate system at the corresponding time point;
and w (t) is the support boundary displacement of the monitoring point in the z direction of a preset stereo coordinate system at the corresponding time point.
In a second aspect, there is provided a maritime work support structure fatigue analysis system fused with measured data, the system comprising:
the parameter segmentation unit is used for segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
a theoretical structure stress calculation unit, configured to combine any of the poisson ratio threshold sub-values, the elastic modulus threshold sub-values, and the shear modulus threshold sub-values, with the support boundary stress and the support boundary displacement obtained through monitoring, and obtain corresponding theoretical structure stresses according to a preset stress distribution mechanism model;
the optimal empirical parameter group acquisition unit is used for selecting a time period, and when the total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is determined to be minimum, the corresponding Poisson ratio threshold sub-value, the elastic modulus threshold sub-value and the shear modulus threshold sub-value form an optimal empirical parameter combination;
and the fatigue analysis unit is used for obtaining the structural stress distribution condition through calculation of a stress distribution mechanism model according to the optimal empirical parameter combination, the measured structural stress and the supporting boundary stress, and further carrying out structural fatigue analysis according to the structural stress distribution condition by combining finite element numerical calculation.
Specifically, the optimal experience parameter group obtaining unit is specifically configured to select a number of experience parameters, and perform step-wise equal difference splitting on a preset poisson ratio threshold range, an elastic modulus threshold range, and a shear modulus threshold range according to the number of experience parameters, so as to obtain a plurality of poisson ratio threshold sub-values, elastic modulus threshold sub-values, and shear modulus threshold sub-values.
The technical scheme who provides this application brings beneficial effect includes:
the application provides a maritime work support structure fatigue analysis method and system fusing measured data, and the empirical parameters are subjected to split simulation, so that the empirical parameters are optimized, a data basis is provided for the reliability of fatigue analysis, and help is provided for maritime work support structure fatigue analysis.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic diagram illustrating steps of a maritime work support structure fatigue analysis method fused with measured data according to embodiment 1 of the present application;
fig. 2 is a schematic diagram of sensor layout of the maritime work support structure fatigue analysis method fused with measured data provided in embodiment 1 of the present application;
FIG. 3 is a schematic flow chart of a marine engineering support structure fatigue analysis method incorporating measured data according to embodiment 1 of the present application;
fig. 4 is a stress distribution effect diagram simulated by using ANSYS in the maritime work support structure fatigue analysis method fused with actually measured data provided in embodiment 1 of the present application;
fig. 5 is a block diagram of a marine supporting structure fatigue analysis system fusing measured data provided in embodiment 2 of the present application;
reference numerals are as follows:
1. a parameter dividing unit; 2. a theoretical structural stress calculation unit; 3. an optimum experience parameter group acquisition unit; 4. and a fatigue analysis unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. 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 application.
Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
The embodiment of the invention provides a maritime work support structure fatigue analysis method and system fusing measured data, which are used for splitting and simulating experience parameters, so that the experience parameters are optimized, a data basis is provided for the reliability of fatigue analysis, and the fatigue analysis of a maritime work support structure is helped.
In order to achieve the technical effects, the general idea of the application is as follows:
a maritime work support structure fatigue analysis method fusing measured data comprises the following steps:
s1, segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
s2, randomly combining each Poisson ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value, combining the support boundary stress and the support boundary displacement obtained by monitoring, and obtaining corresponding theoretical structural stress according to a preset stress distribution mechanism model;
s3, selecting a time period, and when the total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is minimum, forming an optimal empirical parameter combination by using a Poisson ratio threshold sub-value, an elastic modulus threshold sub-value and a shear modulus threshold sub-value corresponding to the theoretical structural stress;
and S4, according to the optimal empirical parameter combination, the structural stress and the supporting boundary stress, calculating through a stress distribution mechanism model to obtain the structural stress distribution condition, and further performing structural fatigue analysis according to the structural stress distribution condition by combining finite element numerical calculation.
Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
Example 1
Referring to fig. 1 to 4, an embodiment of the present invention provides a maritime work support structure fatigue analysis method fusing measured data, including the following steps:
s1, segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
s2, randomly combining each Poisson ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value, combining the support boundary stress and the support boundary displacement obtained by monitoring, and obtaining corresponding theoretical structural stress according to a preset stress distribution mechanism model;
s3, selecting a time period, and when determining that the total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is minimum, combining the corresponding Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value to form an optimal empirical parameter combination;
and S4, according to the optimal empirical parameter combination, the structural stress and the supporting boundary stress, calculating through a stress distribution mechanism model to obtain the structural stress distribution condition, and further performing structural fatigue analysis according to the structural stress distribution condition and by combining finite element numerical calculation.
According to the method and the device, the empirical parameters are subjected to split simulation, so that the empirical parameters are optimized, a data basis is provided for the reliability of fatigue analysis, and help is provided for the fatigue analysis of the marine supporting structure.
It should be noted that, before the preset poisson's ratio threshold range, elastic modulus threshold range and shear modulus threshold range are subjected to the segmentation processing, the method further includes the following steps:
and monitoring the measurement structure stress, the supporting boundary stress and the supporting boundary displacement of each monitoring point of the marine engineering supporting structure in real time.
Specifically, the stress of the measurement structure corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset first stress sensor, the stress of the supporting boundary corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset second stress sensor, and the displacement of the supporting boundary corresponding to the monitoring point of the maritime work support structure is monitored in real time by using a preset displacement sensor.
The arrangement quantity and the orientation of the first stress sensor, the second stress sensor and the displacement sensor are adaptively adjusted according to the specific structure condition, the cost and the operation difficulty of the marine engineering supporting structure.
Specifically, supporting the boundary stresses includes: f. of x (t)、f y (t) and f z (t)；
f x (t) measuring structural stress of the monitoring point at the corresponding time point in the x direction of a preset three-dimensional coordinate system;
f y (t) measuring structural stress of the monitoring point at the corresponding time point in the y direction of a preset three-dimensional coordinate system;
f z and (t) measuring the structural stress of the monitoring point at the corresponding time point in the z direction of a preset three-dimensional coordinate system.
Specifically, the support boundary displacement includes: u (t), v (t), w (t);
u (t) is the support boundary displacement of the monitoring point at the corresponding time point in the x direction of the preset three-dimensional coordinate system;
v (t) is the support boundary displacement of the monitoring point at the corresponding time point in the y direction of the preset stereo coordinate system;
and w (t) is the support boundary displacement of the monitoring point in the z direction of the preset stereo coordinate system at the corresponding time point.
In the embodiment of the application, the emphasis is on obtaining the optimal empirical parameter combination, and since the empirical parameters have a large influence on the result of the structural fatigue analysis, how to obtain the appropriate empirical parameters is very important.
Specifically, for a preset poisson ratio threshold range, an elastic modulus threshold range and a preset shear modulus threshold range, a plurality of poisson ratio threshold sub-ranges, elastic modulus sub-threshold ranges and shear modulus threshold sub-ranges are obtained, and the method specifically comprises the following steps of:
selecting the number of empirical parameters, and respectively carrying out step-by-step equal difference splitting on a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range according to the number of the empirical parameters to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values.
In specific implementation, the Poisson ratio of the marine supporting structure is recorded as mu, and the threshold range of the Poisson ratio is [ mu ] a ，μ b 】；
The elastic modulus of the marine supporting structure is recorded as E, and the threshold range of the elastic modulus is [ E ] a ，E b 】；
The shear modulus of the marine supporting structure is recorded as G, and the threshold range of the shear modulus is [ G ] a ，G b 】；
Selecting the number of the empirical parameters as n +1, and respectively carrying out step type equal difference splitting on the Poisson ratio threshold range, the elastic modulus threshold range and the shear modulus threshold range according to the number of the empirical parameters;
the multiple Poisson ratio threshold sub-values are respectively mu a ，
Multiple threshold modulus of elasticityRespectively has a value of E a ，
A plurality of shear modulus threshold sub-values are respectively G a ，
The Poisson ratio threshold sub-value, the elastic modulus threshold sub-value and the shear modulus threshold sub-value are arbitrarily combined, each empirical parameter has (n + 1) forms, and (n + 1) is total 3 And (4) a combination mode.
Furthermore, the existence of the empirical parameter (n + 1) 3 In combination, thus aiming at (n + 1) 3 Each input condition of the empirical parameter combination mode can be used for calculating theoretical stress f '(p) of m points on the marine supporting structure according to the force distribution mechanism model f' (p, t) 1 ,t)，f'(p 2 ,t)...f'(p m T); wherein the content of the first and second substances,
f'(p 1 t) theoretical structural stress of the first monitoring point, f' (p) 2 T) theoretical structural stress of the second monitoring point, f' (p) m And t) is the theoretical structural stress of the m-th monitoring point.
Specifically, the calculation formula of the total error between the measured structural stress and the theoretical structural stress of all the monitoring points is as follows:
the calculation formula of the total error of the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is as follows:
wherein the content of the first and second substances,
t a ～t b for a corresponding time period, i.e., [ t ] a ，t b 】，f(p 1 T) measured structural stress at the corresponding time point of the first monitoring point, f (p) 2 T) measured structural stress at the second monitoring point at the corresponding time point, f (p) m T) is the measured structural stress of the mth monitoring point at the corresponding time point;
f'(p 1 t) theoretical structural stress at the first monitoring point at the corresponding time point, f' (p) 2 T) theoretical structural stress at the corresponding time point of the second monitoring point, f' (p) m T) is the theoretical structural stress of the mth monitoring point at the corresponding time point,
for convenience of expression, p denotes the specific position in space, xyz, which refers to the coordinate position (x, y, z) in space of the support structure.
And when the total error of the measured structural stress and the theoretical structural stress of all monitoring points corresponding to the time period is determined to be the minimum according to the minimum value of the total error, the corresponding Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value are combined to form the optimal empirical parameter combination, and the Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value are empirical parameters required by the user in the subsequent structural fatigue analysis, so that the reliability of the structural fatigue analysis result can be improved to a certain extent.
It should be noted that, according to the optimal empirical parameter combination, the structural stress is measured, and the supporting boundary stress, the structural stress distribution condition is obtained through the stress distribution mechanism model calculation, and further, when the structural fatigue analysis is performed according to the structural stress distribution condition by combining with the finite element numerical calculation, the method specifically includes:
determine any period of time [ t ] in the manner described above a ，t b The optimal empirical parameter combination of the internal empirical parameters can obtain the high-precision and complete stress distribution of the marine supporting structure through the calculation of a stress distribution mechanism model;
on the basis, the high stress area can be calculated according to the material fatigue S-N curve, so that the fatigue life of the marine engineering supporting structure can be predicted more accurately;
of course, it is also possible to use mature finite element analysis software, such as ANSYS finite element calculation software, which is a large-scale general finite element analysis software integrating structure, fluid, electric field, magnetic field, and sound field analysis.
Here, a stress distribution mechanism model is introduced, a plurality of basic equations, namely, a balance differential equation, a geometric equation, a physical equation and a deformation coordination equation, are configured in the stress distribution mechanism model, and the problem needs to be analyzed in the elastic mechanics from three aspects: statics, geometry, and physics;
assuming a tiny right parallelepiped of the object to be extracted, its dimensions in the x, y and z directions are d x 、d y And d z . And performing static solution under different boundary conditions according to the static balance conditions, the geometric equation, the physical equation and the deformation coordination equation.
The details of the basic equation are as follows:
1. equilibrium differential equation:
the balance differential equation describes a relational expression of a stress component and an external force component, and the following balance differential equation can be obtained according to static balance conditions:
in the formula:
σ x is positive stress in the x direction, σ y Positive stress in the x direction, σ z Positive stress in the x direction;
τ xy is xyPlane shear stress, τ yz Is yz plane shear stress, τ xz Is xz plane shear stress;
f x external force in the x direction, f y External force in the y direction, f z Is an external force in the z direction.
2. The geometric equation is as follows:
the geometric equation describes the relationship between the strain component and the displacement component, and the expression is as follows:
in the formula:
ε x is positive strain in the x direction, ε y Is positive strain in the y direction, ε z Is z direction positive strain;
γ xy is xy plane shear strain, γ yz Is yz plane shear strain, gamma xz Is xz plane shear strain;
u is the x-direction displacement, v is the y-direction displacement, and w is the z-direction displacement.
3. Physical equation:
the physical equation is a relational expression describing the strain component and the stress component. For isotropic materials, the following expression can be established according to hooke's law:
in the formula:
mu is Poisson's ratio;
e is the modulus of elasticity;
g is shear modulus;
strain parameter epsilon x 、ε y 、ε z ，γ xy 、γ yz 、γ zx Is consistent with the formula;
stress parameter sigma x 、σ y 、σ z ，τ xy 、τ yz 、τ zx In accordance with the above formula.
4. Deformation coordination equation:
the deformation coordination equation, also known as the deformation continuity equation or the compatibility equation, describes the relationship that exists between the six stress components.
Expression of normal stress and shear strain in the same plane:
in the formula:
strain parameter epsilon x 、ε y 、ε z ，γ xy 、γ yz 、γ zx Is consistent with the formula;
stress parameter sigma x 、σ y 、σ z ，τ xy 、τ yz 、τ zx In accordance with the above formula.
The expression of normal stress and shear strain in non-coplanar planes:
in the formula:
strain parameter epsilon x 、ε y 、ε z ，γ xy 、γ yz 、γ zx Is consistent with the formula;
stress parameter sigma x 、σ y 、σ z ，τ xy 、τ yz 、τ zx In accordance with the above formula.
The mathematical meaning of the deformation coordination equation: so that the six geometric equations do not contradict. Physical significance of the deformation coordination equation: if the deformation of the object does not satisfy a certain relationship, the deformed unit bodies cannot be recombined into a continuous body, and gaps or embedding phenomena are generated between the deformed unit bodies. The strain components must satisfy the relationship in order for the deformed object to remain a continuum.
It should be noted that, the stress component of each cell cannot be solved by any of the above equations, and the stress distribution of one cell is solved, and it is determined by combining a balanced differential equation, a geometric equation, a physical equation (i.e., hooke's law), and a deformation coordination equation to solve the equations.
For the supporting structure, the boundary stress parameter and the boundary displacement parameter are measured and used as input, and the stress distribution of the boundary unit can be solved; the stress distribution results of the boundary elements are used as input, and the stress distribution of other elements can be gradually obtained, which is a method for finite element numerical calculation.
The finite element method is also called as finite element method, the basic idea is to disperse the solution domain of a structure or continuum into a plurality of subdomains (units), two adjacent units are only connected with each other through a plurality of points, each connection point is called as a node, and the nodes on the boundary of all the units are connected with each other to form a complex. The finite element method is to establish an algebraic equation set or a differential equation set for solving basic unknowns by an equivalent variational principle or a weighted residue method of a mathematical model (basic equation and boundary condition) of an original problem. This equation is called a finite element solution equation and is expressed in matrix form. This equation is then solved numerically to obtain a solution to the problem. The finite element modeling content mainly comprises the following two steps:
grid division: the structure is dispersed (divided) into finite units according to a certain rule;
boundary processing: the constraints and loads acting on the structure boundaries are treated as node constraints and node loads.
In summary, the basic equation is used to solve the stress distribution of each unit, and then the finite element numerical calculation is used to solve the stress distribution of the whole structure.
Example 2
Referring to fig. 5, an embodiment of the present invention provides a maritime work support structure fatigue analysis system based on the fused measured data of embodiment 1, where the system includes:
the parameter segmentation unit 1 is used for segmenting a preset poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
the theoretical structure stress calculation unit 2 is used for randomly combining each Poisson ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value, combining the support boundary stress and the support boundary displacement obtained by monitoring, and obtaining each corresponding theoretical structure stress according to a preset stress distribution mechanism model;
the optimal empirical parameter group acquisition unit 3 is used for selecting a time period, determining that when the total error between the measured structural stress and the theoretical structural stress of all monitoring points corresponding to the time period is minimum, and combining the corresponding Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value into an optimal empirical parameter combination;
and the fatigue analysis unit 4 is used for obtaining the structural stress distribution condition through calculation of a stress distribution mechanism model according to the optimal empirical parameter combination, the measured structural stress and the support boundary stress, and further performing structural fatigue analysis according to the structural stress distribution condition by combining finite element numerical calculation.
According to the embodiment of the application, the empirical parameters are subjected to split simulation, so that the empirical parameters are optimized, data basis is provided for reliability of fatigue analysis, and help is provided for fatigue analysis of the marine engineering supporting structure.
It should be noted that, before performing segmentation processing on the preset poisson ratio threshold range, elastic modulus threshold range and shear modulus threshold range, the method further includes the following steps:
and monitoring the measurement structure stress, the supporting boundary stress and the supporting boundary displacement of each monitoring point of the marine engineering supporting structure in real time.
Specifically, the stress of the measuring structure corresponding to the monitoring point of the maritime work supporting structure is monitored in real time by a preset first stress sensor, the stress of the supporting boundary corresponding to the monitoring point of the maritime work supporting structure is monitored in real time by a preset second stress sensor, and the displacement of the supporting boundary corresponding to the monitoring point of the maritime work supporting structure is monitored in real time by a preset displacement sensor.
The arrangement quantity and the orientation of the first stress sensor, the second stress sensor and the displacement sensor are adaptively adjusted according to the specific structure condition, the cost and the operation difficulty of the marine engineering supporting structure.
Specifically, supporting the boundary stresses includes: f. of x (t)、f y (t) and f z (t)；
f x (t) measuring structural stress of the monitoring point at the corresponding time point in the x direction of a preset three-dimensional coordinate system;
f y (t) measuring structural stress of the monitoring point at the corresponding time point in the y direction of a preset three-dimensional coordinate system;
f z and (t) measuring the structural stress of the monitoring point at the corresponding time point in the z direction of a preset three-dimensional coordinate system.
Specifically, the support boundary displacement includes: u (t), v (t), w (t);
u (t) is the support boundary displacement of the monitoring point at the corresponding time point in the x direction of the preset three-dimensional coordinate system;
v (t) is the support boundary displacement of the monitoring point at the corresponding time point in the y direction of the preset stereo coordinate system;
and w (t) is the support boundary displacement of the monitoring point in the z direction of the preset stereo coordinate system at the corresponding time point.
In the embodiment of the application, the emphasis is on obtaining the optimal empirical parameter combination, and since the empirical parameters have a large influence on the result of the structural fatigue analysis, how to obtain the appropriate empirical parameters is very important.
The optimal experience parameter group obtaining unit 3 is specifically configured to select a number of experience parameters, and perform step-wise equal difference splitting on a preset poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range according to the number of the experience parameters, so as to obtain a plurality of poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values.
In specific implementation, the Poisson ratio of the marine supporting structure is recorded as mu, and the threshold range of the Poisson ratio is [ mu ] a ，μ b 】；
The elastic modulus of the marine supporting structure is recorded as E, and the threshold range of the elastic modulus is [ E ] a ，E b 】；
The shear modulus of the marine supporting structure is recorded as G, and the threshold range of the shear modulus is [ G ] a ，G b 】；
Selecting the number of experience parameters as n +1, and respectively carrying out step-by-step equal difference resolution on the Poisson ratio threshold range, the elastic modulus threshold range and the shear modulus threshold range according to the number of the experience parameters;
the multiple Poisson's ratio threshold sub-values are respectively mu a ，
The threshold values of the elastic modulus are respectively E a ，
A plurality of shear modulus threshold sub-values are respectively G a ，
The Poisson ratio threshold sub-value, the elastic modulus threshold sub-value and the shear modulus threshold sub-value are arbitrarily combined, each empirical parameter has (n + 1) forms, and (n + 1) is total 3 And (4) a combination mode.
Furthermore, the existence of the empirical parameter (n + 1) 3 In combination, thus aiming at (n + 1) 3 Each input condition of the empirical parameter combination mode can be used for calculating theoretical stress f '(p) of m points on the marine supporting structure according to the force distribution mechanism model f' (p, t) 1 ,t)，f'(p 2 ,t)…f'(p m T); wherein the content of the first and second substances,
f'(p 1 t) theoretical structural stress of the first monitoring point, f' (p) 2 T) theoretical structural stress of the second monitoring point, f' (p) m And t) is the theoretical structural stress of the m-th monitoring point.
Specifically, the calculation formula of the total error between the measured structural stress and the theoretical structural stress of all the monitoring points is as follows:
the calculation formula of the total error of the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is as follows:
wherein, the first and the second end of the pipe are connected with each other,
t a ～t b for a corresponding time period, i.e., [ t ] a ，t b 】，f(p 1 T) measured structural stress at the first monitoring point at the corresponding time point, f (p) 2 T) measured structural stress at the second monitoring point at the corresponding time point, f (p) m T) is the measured structural stress of the mth monitoring point at the corresponding time point;
f'(p 1 t) theoretical structural stress at the first monitoring point at the corresponding time point, f' (p) 2 T) theoretical structural stress at the corresponding time point of the second monitoring point, f' (p) m T) is when the m monitoring point corresponds toThe theoretical structural stress at the intermediate point is,
for convenience of expression, p denotes the specific position in space, xyz, which refers to the coordinate position (x, y, z) in space of the support structure.
And when the total error of the measured structural stress and the theoretical structural stress of all monitoring points corresponding to the time period is determined to be the minimum according to the minimum value of the total error, the corresponding Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value are combined to form the optimal empirical parameter combination, and the Poisson ratio threshold sub-value, elastic modulus threshold sub-value and shear modulus threshold sub-value are empirical parameters required by the user in the subsequent structural fatigue analysis, so that the reliability of the structural fatigue analysis result can be improved to a certain extent.
It should be noted that, according to the optimal empirical parameter combination, the structural stress is measured, and the supporting boundary stress, the structural stress distribution condition is obtained through the stress distribution mechanism model calculation, and further, when the structural fatigue analysis is performed according to the structural stress distribution condition by combining with the finite element numerical calculation, the method specifically includes:
determining any period of time [ t ] in the manner described above a ，t b The optimal empirical parameter combination of the internal empirical parameters can obtain the high-precision and complete stress distribution of the marine supporting structure through the calculation of a stress distribution mechanism model;
on the basis, the high stress area can be calculated according to the material fatigue S-N curve, so that the fatigue life of the marine engineering supporting structure can be predicted more accurately;
of course, it is also possible to use mature finite element analysis software, such as ANSYS finite element calculation software, which is a large-scale general finite element analysis software integrating structure, fluid, electric field, magnetic field, and sound field analysis.
It should be noted that in this application, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A maritime work support structure fatigue analysis method fused with measured data is characterized by comprising the following steps:
segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
randomly combining each Poisson's ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value, combining the support boundary stress and the support boundary displacement obtained by monitoring, and obtaining corresponding each theoretical structural stress according to a preset stress distribution mechanism model;
selecting a time period, and when the total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is minimum, combining the Poisson ratio threshold sub-value, the elastic modulus threshold sub-value and the shear modulus threshold sub-value corresponding to the theoretical structural stress into an optimal empirical parameter combination;
and calculating to obtain the structural stress distribution condition through a stress distribution mechanism model according to the optimal empirical parameter combination, the measured structural stress and the supporting boundary stress, and further performing structural fatigue analysis according to the structural stress distribution condition by combining finite element numerical calculation.
2. The maritime work support structure fatigue analysis method fused with measured data according to claim 1, wherein: the method specifically comprises the following steps of obtaining a plurality of poisson ratio threshold value sub-ranges, elastic modulus sub-threshold value ranges and shear modulus threshold value sub-ranges for a preset poisson ratio threshold value range, elastic modulus threshold value range and shear modulus threshold value range:
selecting an empirical parameter number, and performing step-by-step equal difference resolution on a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range according to the empirical parameter number to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values.
3. The maritime work support structure fatigue analysis method fusing measured data according to claim 2, characterized in that:
the Poisson ratio of the marine supporting structure is recorded as mu, and the threshold range of the Poisson ratio is [ mu ] a ，μ b 】；
The elastic modulus of the marine supporting structure is recorded as E, and the threshold range of the elastic modulus is [ E ] a ，E b 】；
The shear modulus of the marine supporting structure is recorded as G, and the threshold range of the shear modulus is [ G ] a ，G b 】；
Selecting the number of empirical parameters as n +1, and respectively carrying out step type equal difference splitting on the Poisson ratio threshold range, the elastic modulus threshold range and the shear modulus threshold range according to the number of the empirical parameters;
a plurality of said Poisson ratio threshold sub-values are respectively mu a ，
A plurality of threshold values of the elastic modulus are respectively E a ，
A plurality of said shear modulus threshold sub-values are each G a ，
The Poisson ratio threshold sub-value, the modulus of elasticity threshold sub-value and the shear modulus threshold sub-value are arbitrarily combined, each empirical parameter has (n + 1) forms, and (n + 1) forms are total 3 And (4) a combination mode.
4. The method for fatigue analysis of a maritime work support structure incorporating measured data according to claim 1, wherein before the segmentation process of the preset poisson's ratio threshold range, elastic modulus threshold range and shear modulus threshold range, the method further comprises the steps of:
and monitoring the measurement structure stress, the supporting boundary stress and the supporting boundary displacement of each monitoring point of the marine engineering supporting structure in real time.
5. The maritime work support structure fatigue analysis method fused with measured data according to claim 1, wherein:
the calculation formula of the total error of the measured structural stress and the theoretical structural stress of all the monitoring points is as follows:
the calculation formula of the total error of the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is as follows:
wherein the content of the first and second substances,
t a ～t b for a corresponding time period, f (p) 1 T) is the measured structural stress at the corresponding time point for the first monitoring point z, f (p) 2 T) is the measured structural stress at the corresponding point in time for the second monitoring point, f (p) m T) is the measured structural stress of the mth monitoring point at the corresponding time point;
f'(p 1 t) is the theoretical structural stress at the first monitoring point at the corresponding point in time, f' (p) 2 T) is the theoretical structural stress at the corresponding time point, f' (p), of the second monitoring point m And t) is the theoretical structural stress of the mth monitoring point at the corresponding time point.
6. The maritime work support structure fatigue analysis method fusing measured data according to claim 4, characterized in that:
the method comprises the steps of utilizing a preset first stress sensor to monitor the stress of a measuring structure of the maritime work support structure corresponding to a monitoring point in real time, utilizing a preset second stress sensor to monitor the stress of a supporting boundary of the maritime work support structure corresponding to the monitoring point in real time, and utilizing a preset displacement sensor to monitor the displacement of the supporting boundary of the maritime work support structure corresponding to the monitoring point in real time.
7. The maritime work support structure fatigue analysis method fusing measured data according to claim 6, characterized in that:
the supporting boundary stress includes: f. of x (t)、f y (t) and f z (t)；
F is x (t) the monitoring points are at corresponding time points in the x direction of a preset three-dimensional coordinate systemMeasuring structural stress of (1);
f is described y (t) measuring structural stress of the monitoring point at a corresponding time point in the y direction of a preset three-dimensional coordinate system;
f is z And (t) measuring the structural stress of the monitoring point at the corresponding time point in the z direction of a preset three-dimensional coordinate system.
8. The maritime work support structure fatigue analysis method fusing measured data according to claim 6, characterized in that:
the support boundary displacement includes: u (t), v (t), w (t);
u (t) is the support boundary displacement of the monitoring point in the x direction of a preset stereo coordinate system at the corresponding time point;
v (t) is the support boundary displacement of the monitoring point in the y direction of a preset stereo coordinate system at the corresponding time point;
and w (t) is the support boundary displacement of the monitoring point at the corresponding time point in the z direction of a preset stereo coordinate system.
9. A maritime work support structure fatigue analysis system fused with measured data, the system comprising:
the parameter segmentation unit is used for segmenting a preset Poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range to obtain a plurality of Poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values;
the theoretical structure stress calculation unit is used for randomly combining each Poisson ratio threshold sub-value, each elastic modulus threshold sub-value and each shear modulus threshold sub-value, and obtaining corresponding theoretical structure stress according to a preset stress distribution mechanism model by combining the support boundary stress and the support boundary displacement obtained by monitoring;
an optimal empirical parameter group obtaining unit, configured to select a time period, and when a total error between the measured structural stress and the theoretical structural stress of all the monitoring points corresponding to the time period is determined to be minimum, combine the corresponding poisson ratio threshold sub-value, the elastic modulus threshold sub-value, and the shear modulus threshold sub-value into an optimal empirical parameter combination;
and the fatigue analysis unit is used for calculating and obtaining a structural stress distribution condition through a stress distribution mechanism model according to the optimal empirical parameter combination, the measured structural stress and the supporting boundary stress, and further performing structural fatigue analysis by combining finite element numerical calculation according to the structural stress distribution condition.
10. The maritime work support structure fatigue analysis method fused with measured data according to claim 8, wherein:
the optimal experience parameter group obtaining unit is specifically configured to select an experience parameter number, and perform step-wise equal difference splitting on a preset poisson ratio threshold range, an elastic modulus threshold range and a shear modulus threshold range according to the experience parameter number to obtain a plurality of poisson ratio threshold sub-values, elastic modulus threshold sub-values and shear modulus threshold sub-values.
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