Issue 64

P. Ghannadi et alii, Frattura ed Integrità Strutturale, 64 (2023) 51-76; DOI: 10.3221/IGF-ESIS.64.04

version of SA in structural optimization problems. Over the past two decades, successful applications of the SA have been reported several times. For example, Bureerat and Limtragool [79], Lamberti [80], Sonmez and Tan [81], Tejani et al. [82], Kurtulu ş et al. [83], Najafabadi et al. [84], and Goto et al. [85] are a few to be noted. It is necessary to define an objective function based on measured and calculated modal characteristics to solve the model-based inverse problem of damage detection using optimization algorithms [86]. The inverse analysis using an optimization algorithm attempts to find the optimal design parameters for damage detection by minimizing the differences between the measured and calculated modal characteristics [87,88]. An inverse problem of damage detection has the following mathematical formulation [89]:                1 2 F t ind , ,.. 0 Min , imiz ., 1 1,2 .. o . e Subjec , t Ne e f e Ne (2) where    f denotes the objective function, Ne represents the number of elements, and  is a vector that includes stiffness reduction coefficients [89]. The elemental mass matrix is typically assumed not to alter due to damage, and stiffness coefficients define structural damage [89,90]. If the stiffness coefficient of the e th element is considered to be  e , the global stiffness matrix will be represented as the sum of the damaged and undamaged stiffness matrices [91] and can be expressed as:

     1 1 Ne e

  e

K

K

(3)

e

where K e denotes the stiffness matrix of the e th element and  e is considered in the range of 0 to 1 and indicates the severity of the damage [92]. For example, one of the frequently utilized objective functions in damage detection problems is given by Eqn. (4).

2

    Measured Me i asure d i

Calculated

  

  

m

1



 

 

f

w

(4)

m



i

1

i

where m represents the number of modes considered , w is a weighting factor,  Meas i

ured and  Calcu i

lated are the i th measured

and calculated natural frequencies, respectively [89].

A NALYSIS OF PAPERS ON STRUCTURAL HEALTH MONITORING USING THE SA ALGORITHM (1995-2021) he purposeless strategy for reading scientific articles is to read them like a textbook: start with the title and read through the list of references, taking in each word without any critical thought or analysis. The active reviewers should be able to identify the main structure and answer the following critical questions by skimming the article [93]. This review paper enables the researchers to effectively comprehend the previously published papers' objectives, methodologies, and results. Tab. 2 presents a classified review of the SA algorithm's application in the context of FEM updating, system identification, optimal sensor placement, and especially structural damage detection. T • The objective of this study - Why was it conducted? • The methodology of this study - How was it conducted? • The result and finding of this study - What was found?

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