CN114220195A - Ship structure fatigue evaluation stress acquisition method based on sensor data - Google Patents

Ship structure fatigue evaluation stress acquisition method based on sensor data Download PDF

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CN114220195A
CN114220195A CN202111509681.0A CN202111509681A CN114220195A CN 114220195 A CN114220195 A CN 114220195A CN 202111509681 A CN202111509681 A CN 202111509681A CN 114220195 A CN114220195 A CN 114220195A
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刘玉超
任慧龙
冯国庆
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Harbin Engineering University
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Abstract

The invention belongs to the technical field of stress monitoring of hull structures, and particularly relates to a fatigue evaluation stress acquisition method for a hull structure based on sensor data. After the stress data of the monitoring point position of the structure to be monitored is obtained, the stress data of a reference unit can be obtained by combining a simplified method for obtaining unit stress by node stress and stress relation coefficients among units; and then according to the stress relation coefficient among the units in the research range, the stress data of all the units in the research range can be obtained. When the thickness of the structural plate is smaller than the monitoring range of the sensor, the invention divides the unit size in the corresponding research range of the structure to be monitored, firstly obtains the stress relation coefficient among the equivalent units, and then obtains the stress data of the reference equivalent unit by adopting an area weighted average method based on the unit area and combining the stress data of the corresponding unit. The method and the device realize accurate acquisition of the fatigue evaluation stress of the structure to be monitored, and ensure accurate evaluation of the fatigue state of the hull structure.

Description

Ship structure fatigue evaluation stress acquisition method based on sensor data
Technical Field
The invention belongs to the technical field of stress monitoring of hull structures, and particularly relates to a fatigue evaluation stress acquisition method for a hull structure based on sensor data.
Background
In fatigue monitoring of a ship structure, a right-angle three-way sensor (see fig. 1) is generally arranged at a monitoring point, and real-time stress data of a structure to be monitored is obtained by each sensor; then, the obtained real-time stress data of each direction are synthesized and processed into real-time stress, and the real-time stress is directly input into a fatigue evaluation module of the ship structure to complete the real-time evaluation of the fatigue state of the structure to be monitored, but the stress state of the monitoring point position can only be obtained. In fact, the structure of the fatigue monitoring point correspondences is generally extremely complex, and the location where fatigue failure eventually occurs may not be at the monitoring point location. Therefore, if a fatigue-interested region of a structure to be monitored can be defined and an overall stress state of the region can be obtained, the above-mentioned problem can be solved well. Due to the requirement for acquiring the overall stress state of the fatigue attention area of the hull structure, the idea of adopting a finite element method is considered, and the stress data acquired by the sensors arranged at the monitoring points are combined, so that the acquisition of the overall stress state of the fatigue attention area of the structure to be monitored is further realized. But this requires first giving a method of processing the stress data obtained by the sensors into a fatigue assessment stress of the hull structure. It is generally considered that the monitoring range of the sensor is a × a (a is the size of the sensor), while the range required for fatigue strength evaluation of the ship structure is t × t (t is the plate thickness of the structure to be monitored), and in most cases t ≠ a, so that the structural stress obtained by the sensor is different from the structural stress actually used for fatigue evaluation of the structure to be monitored, and if the stress data obtained by the sensor is directly applied to the overall stress acquisition of the structure to be monitored, accurate evaluation of the fatigue state of the structure to be monitored is inevitably influenced, and the actual stress state of the structure is not easy to be grasped by a person.
Disclosure of Invention
The invention aims to provide a ship structure fatigue evaluation stress acquisition method based on sensor data.
A ship structure fatigue evaluation stress acquisition method based on sensor data comprises the following steps:
step 1: acquiring a structure to be monitored; considering the range t multiplied by t required by the fatigue evaluation of the hull structure, recording the range as an equivalent unit, wherein t is the thickness of the structural plate; taking the monitoring point pq as a starting point, and performing discrete processing on the structure to be monitored by the monitoring range a multiplied by a of the sensor to obtain a discrete model of the structure to be monitored; if t is larger than or equal to a, determining the size range of each equivalent unit with the monitoring point pq as a common node as a research range; if t is less than a, determining the size range of each unit corresponding to the monitoring range of the sensor as a research range;
step 2: application of a specific form of external load F to a discrete model of a structure to be monitoredsUnit load Fs0；
If t is more than or equal to a, acquiring stress data of all units in the research range
Figure BDA0003405283280000011
Selecting one of r units with monitor point pq as common node as reference unit and recording the stress data as
Figure BDA0003405283280000012
Wherein the content of the first and second substances,
Figure BDA0003405283280000013
v ═ 1,2, …, w; calculating to obtain stress relation coefficient between units
Figure BDA0003405283280000021
Figure BDA0003405283280000022
If t is less than a, performing size subdivision on each unit in the research range to obtain each equivalent unit lambda corresponding to each unit; combining a finite element method to obtain stress data of each equivalent unit
Figure BDA0003405283280000023
And selecting the reference equivalent unit therein, recording the stress data as
Figure BDA0003405283280000024
Calculating to obtain each equivalent sheetStress relation coefficient between elements
Figure BDA0003405283280000025
Figure BDA0003405283280000026
And 4, step 4: according to the specific form of external load FsStress data of corresponding monitor point pq position
Figure BDA0003405283280000027
Obtaining stress data of a reference cell
Figure BDA0003405283280000028
Stress relation coefficient between combined units
Figure BDA0003405283280000029
Calculating stress data of all units in the research range
Figure BDA00034052832800000210
Figure BDA00034052832800000211
Figure BDA00034052832800000212
Wherein the content of the first and second substances,
Figure BDA00034052832800000213
for interacting with a particular form of external load FsThe stress relation coefficient between the corresponding units,
Figure BDA00034052832800000214
and 5: if t is more than or equal to a, calculating to obtain equivalent unit stress data for fatigue evaluation of the hull structure according to the following formula
Figure BDA00034052832800000215
Figure BDA00034052832800000216
Wherein the content of the first and second substances,
Figure BDA00034052832800000217
for equivalent units eta for fatigue assessment of hull structures
Figure BDA00034052832800000218
Directional stress data;
Figure BDA00034052832800000219
for equivalent cell stress data
Figure BDA00034052832800000220
Of the acquired unit k
Figure BDA00034052832800000221
Directional stress data; a. thekIs the area of cell k; l is the number of stresses for the equivalent cell
Figure BDA00034052832800000222
The total number of units obtained;
if t is less than a, calculating the stress data of the reference equivalent unit according to the following formula
Figure BDA00034052832800000223
Combined with stress relation coefficient between equivalent units
Figure BDA00034052832800000224
Calculating to obtain stress data of each equivalent unit
Figure BDA00034052832800000225
Figure BDA0003405283280000031
Figure BDA0003405283280000032
Wherein the content of the first and second substances,
Figure BDA0003405283280000033
being equivalent to unit lambda
Figure BDA0003405283280000034
Directional stress data; a. theλIs the area of the equivalent unit λ; p is the total number of equivalent units obtained by subdividing the unit v;
Figure BDA0003405283280000035
as a reference equivalent element
Figure BDA0003405283280000036
Directional stress data;
step 6: obtaining stress data of each equivalent unit with monitor point pq as common node
Figure BDA0003405283280000037
Then, calculating to obtain equivalent node stress data of the monitoring point position
Figure BDA0003405283280000038
Figure BDA0003405283280000039
And 7: equivalent node stress data from acquired monitor point locations
Figure BDA00034052832800000310
Calculating equivalent nodal stress for fatigue assessment of hull structures
Figure BDA00034052832800000311
Figure BDA00034052832800000312
Figure BDA00034052832800000313
When theta is less than or equal to 0.785, taking
Figure BDA00034052832800000314
When theta is greater than 0.785, taking
Figure BDA00034052832800000315
The invention has the beneficial effects that:
the invention can obtain the stress data of all units in the corresponding research range of the structure to be monitored from the stress data of the monitoring point position. After stress data of the monitoring point position of the structure to be monitored is obtained, the stress data of a reference unit can be obtained by combining a simplified method for obtaining unit stress by node stress and stress relation coefficients among units; and then according to the stress relation coefficient among the units in the research range, the stress data of all the units in the research range can be obtained. The invention can realize the acquisition of the stress data of the reference equivalent unit. When the thickness of the structural plate is smaller than the monitoring range of the sensor, the invention provides a method for subdividing each unit in the corresponding research range of a structure to be monitored. The method and the device realize accurate acquisition of the fatigue evaluation stress of the structure to be monitored, and ensure accurate evaluation of the fatigue state of the hull structure.
Drawings
Fig. 1 is a schematic view of a right-angle three-way sensor arrangement.
FIG. 2 is a flow chart of the present invention.
FIG. 3 is a schematic view of the investigation region of the structure to be monitored according to the present invention.
FIG. 4 is a schematic diagram of cell subdivision within a corresponding study range of a structure to be monitored in the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
In the existing ship structure fatigue monitoring, real-time stress data obtained by a sensor is directly input into a structure fatigue evaluation module to complete the real-time evaluation of the fatigue state of a structure to be monitored. But this only allows to obtain the stress state at the location of the monitoring point and does not give the overall stress state of the fatigue interesting area of the structure to be monitored. Therefore, in order to meet the requirement for acquiring the overall stress state of the fatigue attention area of the hull structure, the idea of adopting a finite element method is considered, and the stress data acquired by the sensor is combined, so that the acquisition of the overall stress state of the fatigue attention area of the structure to be monitored is further realized. In fact, the monitoring range of the sensor is different from the range required by the fatigue evaluation of the ship structure, and if the stress data obtained by the sensor is directly applied to the acquisition of the overall stress state of the fatigue attention area of the structure to be monitored, the accurate acquisition of the stress state of the structure is inevitably influenced, and the real stress state of the structure is not easy to grasp by personnel. Therefore, it is necessary to first give a method of processing the stress data obtained by the sensors into fatigue evaluation stress of the hull structure.
In order to solve the problems, the invention adopts and uses the thought of a structure finite element method for reference, reasonably determines a discrete model of the structure to be monitored, and correspondingly determines the research range of the structure to be monitored by combining the relation between the plate thickness t of the structure to be monitored and the monitoring range a of the sensor. Firstly, carrying out structural analysis on a structure to be monitored, and obtaining stress relation coefficients among units in a research range by adopting a stress relation coefficient obtaining method among the units; if t is less than a, the stress relation coefficient among equivalent units in the corresponding research range is required to be obtained. And then, combining the stress data of the monitoring point position obtained by the sensor, and obtaining the stress data of all units in the research range of the structure to be monitored by adopting a simplified method of obtaining the unit stress from the node stress. And finally, the accurate acquisition of the fatigue evaluation stress of the hull structure is realized by adopting the acquisition method of the fatigue evaluation stress of the hull structure. Based on the above, the invention provides a method for acquiring fatigue evaluation stress of a ship structure based on sensor data, and the flow of the method is shown in fig. 2.
The invention aims to provide a method for acquiring fatigue evaluation stress of a ship structure based on sensor data, which is used for reasonably processing stress data acquired by a sensor arranged at a monitoring point of a structure to be monitored of a ship, so that the fatigue evaluation stress of the ship structure is accurately acquired.
Firstly, considering the range required by the fatigue evaluation of the hull structure, taking a monitoring point as a starting point, carrying out discrete processing on the structure by using the monitoring range of a sensor to obtain a discrete model of the structure to be monitored, and correspondingly determining the research range of the structure to be monitored by combining the relation between the plate thickness of the structure to be monitored and the monitoring range of the sensor. Secondly, applying unit load of external load of a certain specific form to the discrete model, obtaining stress data of all units in a corresponding research range, and selecting a certain unit as a reference unit from the units taking the monitoring point as a common node. Then, combining the obtained stress data of each unit in the corresponding research range, and correspondingly obtaining stress relation coefficients among the units by a stress relation coefficient obtaining method among the units; in particular, in case of need, the stress relation coefficient between each equivalent unit in the corresponding research range is also obtained. Secondly, according to stress data of monitoring point positions corresponding to the external load in the form, combining a simplified method for obtaining unit stress through node stress, firstly obtaining stress data of a reference unit; further, stress data of all cells in the study range are obtained correspondingly by combining stress relation coefficients between the cells. And finally, correspondingly processing the stress data of each unit according to the acquisition method of the fatigue evaluation stress of the hull structure, acquiring the stress data of each equivalent unit in a corresponding research range, further acquiring the equivalent node stress data of the monitoring point position, and finally acquiring the equivalent node stress for the fatigue evaluation of the hull structure.
1) Method for acquiring stress relation coefficient between units
Firstly, considering a range t multiplied by t (marked as an equivalent unit, t is the thickness of a structural plate) required by the fatigue evaluation of the ship structure, taking a monitoring point as a starting point, carrying out discrete processing on the structure by using a monitoring range a multiplied by a of a sensor to obtain a discrete model of the structure to be monitored, and determining the size range (t is more than or equal to a, see fig. 3a) of each equivalent unit taking the monitoring point as a common node or the size range (t is less than a, see fig. 3b) of each unit corresponding to the monitoring range of the sensor as a research range. Then, a specific form of external load F is applied to the structure to be monitoredsUnit load Fs0Obtaining stress data for all cells in the corresponding study
Figure BDA0003405283280000051
Finally, combining the stress data of the units
Figure BDA0003405283280000052
Selecting a certain unit from all units taking the monitoring point as a common node as a reference unit, and recording the stress data of the selected unit as
Figure BDA0003405283280000053
Thus, the stress relation coefficient between the structural units to be monitored
Figure BDA0003405283280000054
Can be calculated by the formula (1).
Figure BDA0003405283280000055
In particular, when t < a, it is necessary to subdivide the cells within the above-mentioned respective study range (fig. 3b) to obtain the equivalent cells λ corresponding thereto, see fig. 4; then, combining a finite element method to obtain stress data of each equivalent unit
Figure BDA0003405283280000056
And selecting the reference equivalent unit therein, recording the stress data as
Figure BDA0003405283280000057
Further, the stress relation coefficient between each equivalent unit can be calculated by the formula (2)
Figure BDA0003405283280000058
Figure BDA0003405283280000059
2) Simplified method for obtaining unit stress from node stress
Under some form of external load FsUnder the action of (2), stress data of the position of the monitoring point pq
Figure BDA00034052832800000510
Can be calculated from equation (3):
Figure BDA0003405283280000061
wherein r is the number of all units taking the monitoring point pq as a common node;
Figure BDA0003405283280000062
stress data of the m-th unit with the monitor point pq as a common node.
Combined with external loads F of this typesCorresponding stress relation coefficient between units
Figure BDA0003405283280000063
Stress data at monitor point pq position
Figure BDA0003405283280000064
Can be further expressed as:
Figure BDA0003405283280000065
thus, stress data of the reference cell
Figure BDA0003405283280000066
Can be calculated from equation (5):
Figure BDA0003405283280000067
obtaining stress data of a reference unit in the research range of a structure to be monitored
Figure BDA0003405283280000068
The stress data for each cell in the study range can then be calculated from equation (6):
Figure BDA0003405283280000069
3) method for acquiring fatigue evaluation stress of hull structure
Since the monitoring range of the sensor is different from the range required for the fatigue evaluation of the ship structure, the obtained stress data of each unit in the corresponding research range needs to be processed to obtain the stress data of the equivalent unit for the fatigue evaluation of the structure to be monitored. Specifically, it can be realized by using an area weighted average method based on the cell area.
When t is more than or equal to a, the stress data of the equivalent unit
Figure BDA00034052832800000610
Can be calculated from equation (7):
Figure BDA00034052832800000611
wherein the content of the first and second substances,
Figure BDA00034052832800000612
for equivalent units eta for fatigue assessment of hull structures
Figure BDA00034052832800000613
Directional stress data;
Figure BDA00034052832800000614
for equivalent cell stress data
Figure BDA00034052832800000615
Of the acquired unit k
Figure BDA00034052832800000616
Directional stress data; a. thekIs the area of cell k; l is the number of stresses for the equivalent cell
Figure BDA00034052832800000617
The total number of units acquired.
When t is less than a, the unit stress data takes the monitoring range of the sensor as the unit size
Figure BDA00034052832800000618
Can be expressed as:
Figure BDA0003405283280000071
in the formula (I), the compound is shown in the specification,
Figure BDA0003405283280000072
is in the unit v
Figure BDA0003405283280000073
Directional stress data;
Figure BDA0003405283280000074
being equivalent to unit lambda
Figure BDA0003405283280000075
Directional stress data; a. theλIs the area of the equivalent unit lambda(ii) a p is the total number of equivalent units obtained by subdividing the unit v;
Figure BDA0003405283280000076
as a reference equivalent element
Figure BDA0003405283280000077
Directional stress data.
Reference equivalent cell stress data in conjunction with equation (8)
Figure BDA0003405283280000078
Can be calculated by equation (9):
Figure BDA0003405283280000079
obtaining stress data of the reference equivalent unit
Figure BDA00034052832800000710
Then, the stress relation coefficient between equivalent units is combined
Figure BDA00034052832800000711
Stress data of equivalent units
Figure BDA00034052832800000712
Can be calculated by the formula (10); and obtaining stress data of each equivalent unit with monitor point pq as common node
Figure BDA00034052832800000713
Then, equivalent node stress data of the position of the monitoring point
Figure BDA00034052832800000714
Can be calculated by equation (11).
Figure BDA00034052832800000715
Figure BDA00034052832800000716
Equivalent node stress data from acquired monitor point locations
Figure BDA00034052832800000717
By adopting a corresponding stress synthesis formula (12a), the equivalent node stress for the fatigue evaluation of the hull structure can be calculated
Figure BDA00034052832800000718
Figure BDA00034052832800000719
Figure BDA00034052832800000720
Specifically, from equation (12b), when θ ≦ 0.785, take
Figure BDA00034052832800000721
When theta is greater than 0.785, taking
Figure BDA0003405283280000081
The specific method of the invention is as follows:
1) considering the range t multiplied by t required by the fatigue evaluation of the hull structure, taking the monitoring points as the starting points, carrying out discrete processing on the structure by the monitoring range a multiplied by a of the sensor to obtain a discrete model of the structure to be monitored, and determining the size range (when t is more than or equal to a) of each equivalent unit taking the monitoring points as the common nodes or the size range (when t is less than a) of each unit corresponding to the monitoring range of the sensor as the research range.
2) Applying a specific form of external load F to the structuresUnit load Fs0Obtaining stress data of all units in the corresponding research range of the structure to be monitored
Figure BDA0003405283280000082
Selecting a certain unit taking the monitoring point as a common node as a reference unit; then, according to the method for obtaining the stress relation coefficient between the units, the stress relation coefficient between the units is correspondingly calculated and obtained by the formula (1)
Figure BDA0003405283280000083
3) When t is less than a, carrying out size subdivision on each unit in the corresponding research range to obtain each equivalent unit lambda corresponding to each unit; combining a finite element method to obtain stress data of each equivalent unit
Figure BDA0003405283280000084
Selecting the reference equivalent units, and correspondingly calculating the stress relation coefficient among the equivalent units according to the formula (2)
Figure BDA0003405283280000085
4) According to the external load FsStress data of corresponding monitor point position
Figure BDA0003405283280000086
Combining with a simplified method of obtaining cell stress from nodal stress, the stress data of a reference cell is first obtained from equation (5)
Figure BDA0003405283280000087
Further, stress relation coefficient between the coupling units
Figure BDA0003405283280000088
Stress data of all units in the corresponding research range are correspondingly calculated and obtained by the formula (6)
Figure BDA0003405283280000089
5) According to the acquisition method of the fatigue evaluation stress of the hull structure, when t is more than or equal to a, the value is calculated by a formula (7)Calculating equivalent unit stress data for fatigue evaluation of hull structure
Figure BDA00034052832800000810
When t is less than a, calculating stress data of the reference equivalent unit by the formula (9)
Figure BDA00034052832800000811
Combined with stress relation coefficient between equivalent units
Figure BDA00034052832800000812
Calculating stress data of each equivalent unit according to the formula (10)
Figure BDA00034052832800000813
6) Obtaining stress data of each equivalent unit with monitor point pq as common node
Figure BDA00034052832800000814
Then, calculating to obtain equivalent node stress data of the monitoring point position by the formula (11)
Figure BDA00034052832800000815
7) Equivalent node stress data from acquired monitor point locations
Figure BDA00034052832800000816
Finally obtaining the equivalent node stress for the fatigue evaluation of the hull structure by adopting a stress synthesis formula (14a) and a determination formula (14b) of the synthesized stress
Figure BDA0003405283280000091
The invention provides a ship structure fatigue evaluation stress acquisition method based on sensor data, which realizes accurate acquisition of the ship structure fatigue evaluation stress by reasonably processing the stress data acquired by a sensor arranged at a monitoring point position. The method is characterized in that:
1) the method can obtain the stress data of all units in the corresponding research range of the structure to be monitored from the stress data of the monitoring point position. After stress data of the monitoring point position of the structure to be monitored is obtained, the stress data of a reference unit can be obtained by combining a simplified method for obtaining unit stress by node stress and stress relation coefficients among units; and then according to the stress relation coefficient among the units in the research range, the stress data of all the units in the research range can be obtained.
3) The method can achieve acquisition of the stress data of the reference equivalent unit. When the thickness of the structural plate is smaller than the monitoring range of the sensor, the invention provides a method for subdividing each unit in the corresponding research range of a structure to be monitored, wherein the stress relation coefficient among equivalent units is obtained firstly, and then the stress data of a reference equivalent unit can be obtained by adopting an area weighted average method based on the unit area and combining the stress data of the corresponding unit
4) The method can give stress for fatigue evaluation of the hull structure. The method for acquiring the fatigue evaluation stress of the ship structure realizes accurate acquisition of the fatigue evaluation stress of the structure to be monitored, and ensures accurate evaluation of the fatigue state of the ship structure.
It is further defined that, for the selection of the reference (equivalent) cell, the selection should be performed in the corresponding (equivalent) cell with the monitoring point as the common node, and the (equivalent) cell with the highest stress should be selected.
Further, when t ≧ a, and t/a is a non-integer, taking the monitoring point as a starting point, and as much as possible taking a × a as the unit size for dividing the structure to be monitored, at least the size of each unit taking the monitoring point as a common node should be guaranteed to be a × a.
Further, when t < a, in the case where a/t is a non-integer, the monitor point is used as a starting point, and t × t is used as the cell size of the subdivision cell as much as possible, at least the size of each equivalent cell using the monitor point as a common node is t × t.
It is further defined that the stress relation coefficient between the units is related to the external load form suffered by the structure to be monitored, namely that the stress relation coefficient between the units of the structure to be monitored is a constant value when the structure is determined in a discrete mode for a specific form of external load.
Further limiting, the invention explains a patent method by taking a right-angle three-way sensor as an example in the fatigue monitoring of a ship structure; but can be further popularized, and the method of the invention is also suitable for other sensor arrangement forms in the fatigue monitoring of the ship structure.
Example 1:
a ship structure fatigue evaluation stress acquisition method based on sensor data comprises the following steps:
step 1: acquiring a structure to be monitored; considering the range t multiplied by t required by the fatigue evaluation of the hull structure, recording the range as an equivalent unit, wherein t is the thickness of the structural plate; taking the monitoring point pq as a starting point, and performing discrete processing on the structure to be monitored by the monitoring range a multiplied by a of the sensor to obtain a discrete model of the structure to be monitored; if t is larger than or equal to a, determining the size range of each equivalent unit with the monitoring point pq as a common node as a research range; if t is less than a, determining the size range of each unit corresponding to the monitoring range of the sensor as a research range;
step 2: application of a specific form of external load F to a discrete model of a structure to be monitoredsUnit load Fs0；
If t is more than or equal to a, acquiring stress data of all units in the research range
Figure BDA0003405283280000101
Selecting one of r units with monitor point pq as common node as reference unit and recording the stress data as
Figure BDA0003405283280000102
Wherein the content of the first and second substances,
Figure BDA0003405283280000103
v ═ 1,2, …, w; calculating to obtain stress relation coefficient between units
Figure BDA0003405283280000104
Figure BDA0003405283280000105
If t is less than a, performing size subdivision on each unit in the research range to obtain each equivalent unit lambda corresponding to each unit; combining a finite element method to obtain stress data of each equivalent unit
Figure BDA0003405283280000106
And selecting the reference equivalent unit therein, recording the stress data as
Figure BDA0003405283280000107
Calculating to obtain stress relation coefficient between equivalent units
Figure BDA0003405283280000108
Figure BDA0003405283280000109
And 4, step 4: according to the specific form of external load FsStress data of corresponding monitor point pq position
Figure BDA00034052832800001010
Obtaining stress data of a reference cell
Figure BDA00034052832800001011
Stress relation coefficient between combined units
Figure BDA00034052832800001012
Calculating stress data of all units in the research range
Figure BDA00034052832800001013
Figure BDA00034052832800001014
Figure BDA00034052832800001015
Wherein the content of the first and second substances,
Figure BDA00034052832800001016
for interacting with a particular form of external load FsThe stress relation coefficient between the corresponding units,
Figure BDA00034052832800001017
and 5: if t is more than or equal to a, calculating to obtain equivalent unit stress data for fatigue evaluation of the hull structure according to the following formula
Figure BDA00034052832800001018
Figure BDA0003405283280000111
Wherein the content of the first and second substances,
Figure BDA0003405283280000112
for equivalent units eta for fatigue assessment of hull structures
Figure BDA0003405283280000113
Directional stress data;
Figure BDA0003405283280000114
for equivalent cell stress data
Figure BDA0003405283280000115
Of the acquired unit k
Figure BDA00034052832800001123
Directional stress data; a. thekIs the area of cell k; l is the number of stresses for the equivalent cell
Figure BDA0003405283280000116
The total number of units obtained;
if t is less than a, calculating the stress data of the reference equivalent unit according to the following formula
Figure BDA0003405283280000117
Combined with stress relation coefficient between equivalent units
Figure BDA0003405283280000118
Calculating to obtain stress data of each equivalent unit
Figure BDA0003405283280000119
Figure BDA00034052832800001110
Figure BDA00034052832800001111
Wherein the content of the first and second substances,
Figure BDA00034052832800001112
being equivalent to unit lambda
Figure BDA00034052832800001113
Directional stress data; a. theλIs the area of the equivalent unit λ; p is the total number of equivalent units obtained by subdividing the unit v;
Figure BDA00034052832800001114
as a reference equivalent element
Figure BDA00034052832800001115
Directional stress data;
step 6: in which equivalent elements are obtained with monitor point pq as common nodeStress data
Figure BDA00034052832800001116
Then, calculating to obtain equivalent node stress data of the monitoring point position
Figure BDA00034052832800001117
Figure BDA00034052832800001118
And 7: equivalent node stress data from acquired monitor point locations
Figure BDA00034052832800001119
Calculating equivalent nodal stress for fatigue assessment of hull structures
Figure BDA00034052832800001120
Figure BDA00034052832800001121
Figure BDA00034052832800001122
When theta is less than or equal to 0.785, taking
Figure BDA0003405283280000121
When theta is greater than 0.785, taking
Figure BDA0003405283280000122
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (1)

1. A ship body structure fatigue evaluation stress acquisition method based on sensor data is characterized by comprising the following steps:
step 1: acquiring a structure to be monitored; considering the range t multiplied by t required by the fatigue evaluation of the hull structure, recording the range as an equivalent unit, wherein t is the thickness of the structural plate; taking the monitoring point pq as a starting point, and performing discrete processing on the structure to be monitored by the monitoring range a multiplied by a of the sensor to obtain a discrete model of the structure to be monitored; if t is larger than or equal to a, determining the size range of each equivalent unit with the monitoring point pq as a common node as a research range; if t is less than a, determining the size range of each unit corresponding to the monitoring range of the sensor as a research range;
step 2: application of a specific form of external load F to a discrete model of a structure to be monitoredsUnit load Fs0；
If t is more than or equal to a, acquiring stress data of all units in the research range
Figure FDA0003405283270000011
Selecting one of r units with monitor point pq as common node as reference unit and recording the stress data as
Figure FDA0003405283270000012
Wherein the content of the first and second substances,
Figure FDA0003405283270000013
v ═ 1,2, …, w; calculating to obtain stress relation coefficient between units
Figure FDA0003405283270000014
Figure FDA0003405283270000015
If t is less than a, performing size subdivision on each unit in the research range to obtain each equivalent unit lambda corresponding to each unit;combining a finite element method to obtain stress data of each equivalent unit
Figure FDA0003405283270000016
And selecting the reference equivalent unit therein, recording the stress data as
Figure FDA0003405283270000017
Calculating to obtain stress relation coefficient between equivalent units
Figure FDA0003405283270000018
Figure FDA0003405283270000019
And 4, step 4: according to the specific form of external load FsStress data of corresponding monitor point pq position
Figure FDA00034052832700000110
Obtaining stress data of a reference cell
Figure FDA00034052832700000111
Stress relation coefficient between combined units
Figure FDA00034052832700000112
Calculating stress data of all units in the research range
Figure FDA00034052832700000113
Figure FDA00034052832700000114
Figure FDA00034052832700000115
Wherein the content of the first and second substances,
Figure FDA00034052832700000116
for interacting with a particular form of external load FsThe stress relation coefficient between the corresponding units,
Figure FDA00034052832700000117
and 5: if t is more than or equal to a, calculating to obtain equivalent unit stress data for fatigue evaluation of the hull structure according to the following formula
Figure FDA00034052832700000118
Figure FDA0003405283270000021
Wherein the content of the first and second substances,
Figure FDA0003405283270000022
for equivalent units eta for fatigue assessment of hull structures
Figure FDA0003405283270000023
Directional stress data;
Figure FDA0003405283270000024
for equivalent cell stress data
Figure FDA0003405283270000025
Of the acquired unit k
Figure FDA0003405283270000026
Directional stress data; a. thekIs the area of cell k; l is the number of stresses for the equivalent cell
Figure FDA0003405283270000027
The total number of units obtained;
if t is less than a, calculating the stress data of the reference equivalent unit according to the following formula
Figure FDA0003405283270000028
Combined with stress relation coefficient between equivalent units
Figure FDA0003405283270000029
Calculating to obtain stress data of each equivalent unit
Figure FDA00034052832700000210
Figure FDA00034052832700000211
Figure FDA00034052832700000212
Wherein the content of the first and second substances,
Figure FDA00034052832700000213
being equivalent to unit lambda
Figure FDA00034052832700000214
Directional stress data; a. theλIs the area of the equivalent unit λ; p is the total number of equivalent units obtained by subdividing the unit v;
Figure FDA00034052832700000215
as a reference equivalent element
Figure FDA00034052832700000216
Directional stress data;
step 6: obtaining stress data of each equivalent unit with monitor point pq as common node
Figure FDA00034052832700000217
Then, calculating to obtain equivalent node stress data of the monitoring point position
Figure FDA00034052832700000218
Figure FDA00034052832700000219
And 7: equivalent node stress data from acquired monitor point locations
Figure FDA00034052832700000220
Calculating equivalent nodal stress for fatigue assessment of hull structures
Figure FDA00034052832700000221
Figure FDA00034052832700000222
Figure FDA00034052832700000223
When theta is less than or equal to 0.785, taking
Figure FDA0003405283270000031
When theta is greater than 0.785, taking
Figure FDA0003405283270000032
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