Method and system for optimizing venue latticed shell roof measuring points
Technical Field
The invention relates to the technical field of safety engineering, in particular to a venue latticed shell roof measuring point optimizing method and system.
Background
With the development of modern society and the improvement of living standard of people, the construction of various stadiums is more and more emphasized. These stadiums not only serve as the place of holding the sports event, but also carry many functions such as cultural performance, business activities, etc. Therefore, ensuring the safety and operation efficiency of such structures is particularly important. The latticed shell structure is widely used in the design of roofs of stadiums as a space structure form having high strength, light weight and beautiful appearance. However, the complexity of the reticulated shell structure and the number of large-scale points to be selected present a significant challenge to the optimal placement of the sensor.
When the existing sensor arrangement method is used for processing the measuring point scheme of the complex reticulated shell structure, the main problems of poor sensor arrangement optimizing effect, low solving speed, lack of research on external excitation identification and the like exist. In a stadium reticulated shell structure, the scale of the to-be-selected points is huge, and tens or even hundreds of sensors are usually required to be arranged. Because of the large number of degrees of freedom of the actual structural model, the conventional optimization algorithm often shows problems of low calculation efficiency and low solving speed when processing the large-scale to-be-selected points. To reduce computational complexity, existing studies often employ a simplified model to reduce the site locations to be selected. However, for the abnormal space reticulated shell structure, the simplification process is difficult and may affect the accuracy of the optimization results. Therefore, a high-performance optimization algorithm is needed to solve the problem of large-scale to-be-selected points, and improve the effect and efficiency of sensor arrangement.
Disclosure of Invention
In order to overcome the defects of weak self-adaptive capacity and insufficient prediction precision in the prior art, the main purpose of the invention is to provide a venue latticed shell roof measuring point optimizing method and system.
In order to achieve the above purpose, the invention adopts the following technical scheme that the sensor optimization arrangement method based on a multi-population non-dominant recombination genetic algorithm (MP-RGA) is realized, and comprises the following steps:
The population initialization is to divide the measuring point positions into a plurality of populations (population 1, population 2,..population N) in an initialization stage, and simultaneously perform genetic iterative operation to improve the optimizing capability of an algorithm, and the population initialization needs to be provided with a plurality of population numbers N. Theoretically, the more the number of the multiple groups is, the better, but under the condition that the total number of the groups is unchanged, the more the groups are divided, the less the number of the individuals in a single group is, and the optimal searching capability of an algorithm is seriously reduced.
The calculation fitness is embodied by a fitness value calculated by a fitness function f 1, and when the monitoring points of the complex net shell structure of the stadium are optimized, an MAC matrix is constructed based on a mode vector of the position estimation of the measuring points, and off-diagonal elements in the minimized MAC matrix are selected as the fitness function, namely:
Wherein, MAC ij represents the element of the ith row and jth column in the MAC matrix; and X represents the measurement point position arrangement scheme.
The reverse learning is realized by generating a reverse population corresponding to the original population, reserving individuals with adaptability superior to that of the original population, and eliminating poor individuals in the original population, so that the full search of a solution space is realized.
The population communication is implemented through a population communication ratio alpha and a population communication frequency f, and the population communication ratio and the population communication frequency influence the evolution directions and the similarity of individuals of different species in the process of multiple species communication. And the alternating current ratio and the alternating current frequency of the population are increased, the worst population in each generation in the multiple populations obtains excellent individual increase from the optimal population, and the updating speed of the worst population to the optimal population is increased.
The optimal population is an optimal population obtained by evaluating the population 1, the population 2 and the population N according to the fitness function f fit.
The worst population is the worst population obtained by evaluating population 1, population 2, and population N according to fitness function f fit.
The improved population refers to the introduction of elite individuals of the optimal population into the worst population, and the replacement of a corresponding number of worse individuals.
The self-adaptive population size means that the size of the population is dynamically adjusted according to a scaling ratio of 0.5-1.5, when the average fitness of the population parent individuals is better than that of the parent individuals of the previous generation, the parent of the previous generation is indicated to obtain a better searching effect, and the population size can be reduced. Otherwise, poor searching effect is obtained through iteration, and the population size is increased to improve the searching capability. Specifically, the method is determined according to the fitness value and the sigmoid function and comprises the following steps:
(a) Calculating the rate of change of fitness
(B) Calculating the scaling ratio β=sigmoid (5×α) +0.5
(C) Determining updated population size G N=GN-1 x beta
Wherein f fit_(N-1) represents the fitness value of the generation N-1, f fit_(N) represents the fitness value of the generation N, alpha represents the fitness change rate, beta represents the scaling ratio, G N-1 represents the population size of the generation N-1, and G N represents the population size of the generation N.
The self-adaptive interdigital ensures the diversity of individuals through a non-dominant recombination method, and in the self-adaptive non-dominant recombination operation, each iteration carries out non-dominant recombination on a part of individuals in the population, so as to ensure the diversity of the population and simultaneously avoid the complete destruction of excellent gene segments of the population. The proportion of non-dominant recombination can be determined by measuring the similarity of the variance of the population fitness, and the larger the similarity is, the more population individuals are subjected to non-dominant recombination, and the calculation formula is as follows:
Nr=-ln(D(fitness))·T·Nparent
Where N r represents the number of individuals undergoing non-dominant recombination, D (fitness) represents the variance of the fitness of the parent individuals, T represents a constant of 1/20, and N parent represents the number of parent individuals of the population.
The adaptive mutation means that smaller mutation probability is adopted in the early stage of optimizing and larger mutation probability is adopted in the later stage of optimizing. The mutation strategy can ensure that the algorithm can be quickly converged to the vicinity of the optimal solution in the early stage, and is beneficial to the local convergence of the jump-out in the later stage. The adaptive conversion function also adopts a sigmoid function, and the following formula is specifically calculated.
Where M is a constant of 0.1, and represents that the variation probability is generally not more than 0.1.
The optimal arrangement scheme refers to an optimal scheme obtained when the specified iteration times are completed and the set conditions are met.
Compared with the prior art, the method has the beneficial effects that by optimizing the positions of the measuring points, the arrangement scheme of the measuring points is ensured to reflect the dynamic characteristics of the structure more effectively, so that the accuracy and the reliability of structural health monitoring are improved. By minimizing off-diagonal elements in the MAC (ModalAssuranceCriterion) matrix, the degree of distinction between modal vectors is optimized, modal confusion is reduced, and accuracy of modal parameter identification is improved. The robustness and the efficiency of the algorithm are improved, and the searching efficiency and the global searching capability are improved by dividing a large population into a plurality of populations and simultaneously carrying out genetic iterative operation. By individual exchange among populations, richer genetic diversity is introduced, so that the method is helpful for jumping out of a local optimal solution and finding out a global optimal solution. The characteristic of the MAC matrix is considered in the design of the fitness function, so that the algorithm can effectively evaluate and guide specific structural optimization problems. The dynamic adjustment is performed according to the degree of adaptability convergence, so that the algorithm is ensured to find a satisfactory solution in enough time, and unnecessary calculation is avoided. Through self-adaptive adjustment, diversity of the population is maintained, meanwhile, the convergence of the algorithm is ensured to dynamically adjust the size of the population according to the change of the fitness value, and the method is beneficial to maintaining proper search range and search precision in different stages of the algorithm. By introducing elite individuals in the optimal population into the worst population, the convergence process of the algorithm is accelerated, while maintaining the excellent genetic characteristics of the population.
In conclusion, the optimization of the layout of the measuring points of the latticed shell roof of the venue is realized, the performance of the structural health monitoring system is improved, and meanwhile, the high efficiency of the algorithm and the reliability of the result are ensured. The realization of the technical effects is of great significance to the long-term health monitoring and safety evaluation of engineering structures.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application.
FIG. 1 is a schematic flow diagram of a non-dominant recombinant genetic algorithm of the present invention;
FIG. 2 is a comparative schematic diagram of the effective effects of various algorithms in an embodiment of the invention.
Detailed Description
The invention will be further described with reference to the drawings and embodiments.
The optimization of the monitoring points of the complex latticed shell structure of the stadium is realized by a sensor optimization arrangement method based on a multi-population non-dominant recombination genetic algorithm (MP-RGA), which is shown in figure 1.
The population initialization is to divide the measuring point positions into a plurality of populations (population 1, population 2..population N) in the initialization stage, and simultaneously perform genetic iterative operation to improve the optimizing capability of an algorithm, and the population initialization needs to be provided with a plurality of populations N. Theoretically, the more the number of the multiple groups is, the better, but under the condition that the total number of the groups is unchanged, the more the groups are divided, the less the number of the individuals in a single group is, and the optimal searching capability of an algorithm is seriously reduced.
The fitness is lower than the calculated fitness, the fitness value calculated by the fitness function f 1 is embodied, when the monitoring point of the complex net shell structure of the stadium is optimized in the technical scheme, the MAC matrix is constructed based on the mode vector of the position estimation of the measuring point, and the non-diagonal elements in the minimized MAC matrix are selected as the fitness, namely:
Wherein, MAC ij represents the element of the ith row and jth column in the MAC matrix; Represents the maximum value in the off-diagonal cells in the MAC matrix and X represents the sensor placement scheme. The measuring point position is the sensor position. The design objective of this fitness function is to minimize the sum of the attribute differences between the stations, thereby optimizing the station placement scheme.
Based on the measuring point positions, constructing a MAC matrix, which comprises the following steps:
Acquiring structure dynamic response data at the measuring point position, and estimating modal parameters including modal frequency, damping ratio and modal vector through signal processing;
constructing an M×M MAC matrix, wherein M is the number of identified modalities;
For each off-diagonal element (i, j) in the MAC matrix, calculating the dot product of the ith and jth modal vectors Dividing the dot product result by the product of the norms of the ith and jth modal vectors to obtain a normalized MAC value;
and filling the calculated MAC value into a corresponding position (i, j) of the MAC matrix to obtain the MAC matrix.
Reverse learning is performed by generating a reverse population corresponding to the original population, retaining individuals with fitness superior to that of the original population, and eliminating poor individuals in the original population, so that sufficient search of a solution space is realized.
The population communication is implemented through a population communication ratio alpha and a population communication frequency f, and the population communication ratio and the population communication frequency influence the evolution directions and the similarity of individuals of different species in the process of multiple species communication. And the alternating current ratio and the alternating current frequency of the population are increased, the worst population in each generation in the population obtains excellent individuals from the optimal population, and the updating speed of the worst population to the optimal population is increased.
The optimal population is the optimal population obtained by evaluating the population 1, the population 2 and the population N according to the fitness function f fit.
The worst population refers to the worst population obtained by evaluating population 1, population 2, population N according to fitness function f fit.
Improving a population refers to introducing elite individuals of an optimal population into a worst population, replacing a corresponding number of worse individuals.
The self-adaptive population size means that the size of the population is dynamically adjusted according to a scaling ratio of 0.5-1.5, when the average fitness of parent individuals of the population is better than that of parent individuals of the previous generation, the parent of the previous generation is indicated to obtain a better searching effect, and the population size can be reduced. Otherwise, poor searching effect is obtained through iteration, and the population size is increased to improve the searching capability. Specifically, the method is determined according to the fitness value and the sigmoid function and comprises the following steps:
(a) Calculating the rate of change of fitness
(B) Calculate the scaling ratio β= aigmoid (5×α) +0.5
(C) Determining updated population size G N=GN-1 x beta
Wherein f fit_(N-1) represents the fitness value of the generation N-1, f fit_(N) represents the fitness value of the generation N, alpha represents the fitness change rate, beta represents the scaling ratio, G N-1 represents the population size of the generation N-1, and G N represents the population size of the generation N.
The self-adaptive interdigital ensures the diversity of individuals through a non-dominant recombination method, and in the self-adaptive non-dominant recombination operation, each iteration carries out non-dominant recombination on a part of individuals in the population, so as to ensure the diversity of the population and simultaneously avoid the complete destruction of excellent gene segments of the population. The proportion of non-dominant recombination can be determined by measuring the similarity of the variance of the population fitness, and the larger the similarity is, the more population individuals are subjected to non-dominant recombination, and the calculation formula is as follows:
Nr=-ln(D(fitness))·T·Nparent
Where N r represents the number of individuals undergoing non-dominant recombination, D (fitness) represents the variance of the fitness of the parent individuals, T represents a constant of 1/20, and N parent represents the number of parent individuals of the population.
The adaptive mutation means that smaller mutation probability is adopted in the early stage of optimizing and larger mutation probability is adopted in the later stage of optimizing. The mutation strategy can ensure that the algorithm can be quickly converged to the vicinity of the optimal solution in the early stage, and is beneficial to the local convergence of the jump-out in the later stage. The adaptive conversion function also adopts a sigmoid function, and the following formula is specifically calculated.
Wherein M is a constant of 0.1, which means that the variation probability is generally not more than 0.1.
The optimal arrangement scheme is that when the preset iteration times meet the set condition fitness value and are converged, an individual with the highest fitness is selected as an optimal solution, and the optimal scheme is obtained according to the parameters of the optimal solution.
Examples
The stadium net shell roof measuring point optimizing method is applied to a space net frame roof structure of the western security international football center. The method is characterized in that 30, 50 and 100 sensors are arranged on the roof structure, and a plurality of group non-dominant recombination genetic algorithm (MP-RGA), quantum Genetic Algorithm (QGA) and particle swarm optimization algorithm (PSO) are adopted to perform measurement point optimization to obtain measurement point optimization schemes. In the comparison process, the initial population size of a plurality of non-dominant recombination genetic algorithms (MP-RGAs) is taken as 100, the total population is 3, the population alternating ratio is set to be 0.2, the population alternating frequency is set to be once in every 10 generations of alternating, and the Quantum Genetic Algorithm (QGA) and the particle swarm optimization algorithm (PSO) are taken as single populations, so the population size is taken as 300. Other parameters are set as follows, the QGA method realizes the evolution of the population by using double quantum bit codes and quantum rotation gate functions, the coding length of each gene is 10, the PSO method considers the optimal solution of each generation of the population and the optimal solution of individual history to update the population, the learning factors C1 and C2 in the updating are both 2, and the speed is limited to 10, so that the situation that the optimal solution is skipped due to overlarge movement step length is avoided. For individuals who do not meet the constraints, the QGA method and the PSO method replace with regeneration. To eliminate errors in the test procedure, the above three algorithms were run independently 3 times, and the comparison results are shown in fig. 2. The results show that if 30, 50, 100 sensors are deployed on the roof structure, the MP-RGA converges at the fastest rate, already at 200 iterations. The QGA converges at a rate of about 400 iterations. PSO converges at the slowest rate and only at 1000 times. Regarding the fitness value (f 1), the fitness value of the MP-RGA is between 0.95 and 1.0, the QGA is converged between 0.9 and 0.96, the PSO is converged between 0.7 and 0.85, and after the same number of iterations, the proposed multi-group non-dominant recombination genetic algorithm (MP-RGA) obtains a larger fitness value (f 1) than the Quantum Genetic Algorithm (QGA) and the particle swarm optimization algorithm (PSO), which indicates that the algorithm is more suitable for the measuring point arrangement of a stadium roof structure than the previous method, and the optimal measuring point optimization scheme is obtained.
It is noted that in the present invention, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "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.
The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the scope of the present invention, and all designs which are the same or similar to the present invention are within the scope of the present invention.