Statistical Methods for Data Analysis

Vuchkov, Ivan N.; Boyadjieva, Lidia N.

doi:10.1007/978-94-009-0009-7_2

Cited by 7 publications

(8 citation statements)

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“…Regression analyses and optimisations were performed using QStabLab software [23]. The optimisations are based on regression models.…”

Section: Methodsmentioning

confidence: 99%

“…More accurate results are obtained after mathematically modelling the studied mechanical characteristics. An analysis of variance (ANOVA) was conducted via QStatLab [23] to investigate the significance of the governing factors. Figure 19 provides the main ANOVA effects.…”

Section: Effect Of Heat Treatment On Mechanical Characteristics: Plan...mentioning

confidence: 99%

“…where {X} denotes the vector the governing factors, m represents the number of governing factors, and q indicates the number of objective functions. The regression analyses were performed using QStatLab [23], and Table 4 presents the regression coefficients. The magnitude (absolute value) of the coefficients in front of the dimensionless variables indicates the significance of the corresponding governing factor (variable), and the absolute value of the coefficients in front of the products of the variables indicates the significance of the interaction between the governing factors.…”

Section: Effect Of Heat Treatment On Mechanical Characteristics: Plan...mentioning

confidence: 99%

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Influence of an Ageing Heat Treatment on the Mechanical Characteristics of Iron-Aluminium Bronze with -Transformation: Modelling and Optimization

Maximov,

Duncheva,

Anchev

et al. 2023

Preprint

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Aluminium bronzes possess a unique combination of high strength and wear and corrosion resistance in aggressive environments; thus, these alloys find wide application in marine, shipbuilding, aviation, railway, offshore platform applications and other fields. Iron-aluminium bronzes (IABs) are the cheapest and most widely used. When the aluminium content is above 9.4 wt%, IAB is biphasic (i.e. it undergoes -transformation) and can be subjected to all heat-treatment types depending on the desired operating behaviour of the bronze component. This article presents correlations (mathematical models) between the primary mechanical characteristics (yield limit, tensile strength, elongation, hardness and impact toughness) and the ageing temperature and time of quench at 920°C in water Cu-11Al-6Fe bronze, obtained using the centrifugal casting method. The microstructure evolution was evaluated depending on the ageing temperature and time changes. Overall, the research was conducted in three successive inter-related stages: a one-factor-at-a-time study, planned experiment, and optimisations. Four optimisation tasks, which have the greatest importance for practice, were formulated and solved. The defined multiobjective optimisation tasks were solved by searching for the Pareto-optimal solution approach. The decisions were made through a nondominated sorting genetic algorithm (NSGA-II) using QstatLab. The optimisation results were verified experimentally. Additional samples were made for this purpose, quenched at 920°C in water and subjected to subsequent ageing with the optimal values of the governing factors (ageing temperature and time) for the corresponding optimisation task. The comparison of the results for the mechanical characteristics with the theoretical optimisation results presents good agreement.

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“…Regression analyses and optimisations were performed using QStabLab software [23]. The optimisations are based on regression models.…”

Section: Methodsmentioning

confidence: 99%

Section: Effect Of Heat Treatment On Mechanical Characteristics: Plan...mentioning

confidence: 99%

Section: Effect Of Heat Treatment On Mechanical Characteristics: Plan...mentioning

confidence: 99%

See 1 more Smart Citation

Influence of an Ageing Heat Treatment on the Mechanical Characteristics of Iron-Aluminium Bronze with -Transformation: Modelling and Optimization

Maximov,

Duncheva,

Anchev

et al. 2023

Preprint

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“…A regression analysis was performed on the FEM results listed in Table 3 using the QStatLab package (Vuchkov and Vuchkov, 2009 …”

Section: Fem Optimization Of Slide Diamond Burnishing Of Rail-end-bolmentioning

confidence: 99%

Enhancement of fatigue life of rail-end-bolt holes by slide diamond burnishing

Maximov¹,

Duncheva²,

Anchev³

et al. 2014

10.5267/j.esm

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The fatigue failure around rail-end-bolt holes is particularly dangerous since it leads to derailment of trains and consequently to inevitable accidents. It is well-known that the fatigue life of structural holed components, subjected to cyclic load, can be increased by generating compressive hoop stresses around the holes. These beneficial residual compressive stresses significantly reduce the maximum values of the operating tensile stresses arising at the critical points of the components and thus impede the formation of first mode cracks. A new approach to enhancement of fatigue life of rail-end-bolt holes has been developed. The approach involves sequential drilling and reaming through a new combined tool and then slide diamond burnishing by a new device. The technology implementation was carried out on machine tool. The process of creating residual stresses has been studied both experimentally and numerically. The experimental study was conducted by means of a modified split ring method. A reliable finite element modeling approach to the slide diamond burnishing process was developed. On this basis, the process was optimized by means of a genetic algorithm. As a result, the optimal combination of the governing process parameters is established, which ensures both maximum depth of the compressive zone and maximum absolute values of the residual stresses.

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“…Because the experimental approach does not use information about the mechanism of ongoing phenomena [14,15], the numerical procedure used as a tool in this article turns out to be very universal. Each case under consideration can be described with the same structure, but with different coefficients.…”

Section: Introductionmentioning

confidence: 99%

Determination of the optimal mode of laser surface marking of aluminium composite panels with CO2 laser

Yankov¹,

Minev²,

Tonchev³

et al. 2022

tribomat

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This research examines an approach for finding the optimal modes of laser treatment with CO2 laser on advertisement boards made of aluminium composite panels. To achieve the optimal area of the processing mode, an experimental methodology has been developed and an experiment has been planned for finding the limits at the given parameters of the speed and power to obtain an optimisation model. The optimal results are obtained at speeds from 100 to 200 mm/s along the x and y operative axes, as well as the power limits from 5 to 7.5 W to obtain a clear and well-defined image. The defined theoretical mode, obtained because of multicriteria optimisation, is implemented in practice. It is defined as having the relatively best quality image obtained in the shortest time.

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Statistical Methods for Data Analysis

Cited by 7 publications

References 0 publications

Influence of an Ageing Heat Treatment on the Mechanical Characteristics of Iron-Aluminium Bronze with -Transformation: Modelling and Optimization

Influence of an Ageing Heat Treatment on the Mechanical Characteristics of Iron-Aluminium Bronze with -Transformation: Modelling and Optimization

Enhancement of fatigue life of rail-end-bolt holes by slide diamond burnishing

Determination of the optimal mode of laser surface marking of aluminium composite panels with CO2 laser

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