Parameter identification and dynamic response analysis of a modified Prandtl–Ishlinskii asymmetric hysteresis model via least-mean square algorithm and particle swarm optimization

Proceedings of the Institution of Mechanical Engineers, Part L:

et al. 2022

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A novel dynamic soil-structure interaction model is developed for analysis for Euler–Bernoulli beam rests on a spatially random transversely isotropic viscoelastic foundation subjected to moving and oscillating loads. The dynamic equilibrium equation of beam-soil system is established using the extended Hamilton's principle, and the corresponding partial differential equations describing the displacement of beam and soil and boundary conditions are further obtained by the variational principles. These partial differential equations are discretized in spatial and time domains and solved by the finite difference (FD) method. After the differential equations of beam and soil are discretized in the spatial domain, the implicit iterative scheme is used to solve the equations in the time domain. The solving result shows the FD method is effective and convenient for solving the differential equations of beam-soil system. The spring foundation model adopted the modified Vlasov model, which is a two-parameter model considering the compression and shear of soil. The advantage of the present foundation model is avoided estimating input parameters of the modified Vlasov model using prior knowledge. The present solution is verified by publishing solution and equivalent three-dimensional FE analysis. The present model produced an accurate, faster, and effective displacement response. A few examples are carried out to analyze the parameter variation influence for beam on spatially random transversely isotropic viscoelastic soil under moving loads.

Section: Discrete Differential Equationsmentioning

confidence: 99%

“…Evaluation of stress and strain in an arbitrary location in soil, due to the action of external loads, has been a classical topic. [7][8][9][10][11][12][13][14][15] Traditional foundation models can be divided into two types, considering the soil as a soil-spring model, and considering soil as a continuous medium.…”

Section: Introductionmentioning

confidence: 99%

Dynamic response analysis of Euler–Bernoulli beam on spatially random transversely isotropic viscoelastic soil

Feng

Proceedings of the Institution of Mechanical Engineers, Part L:

et al. 2022

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“…where ψ S is the rate of microprestress evolution and may be defined in the same way as equation (20). Based on experimental data:…”

Section: S(t)mentioning

confidence: 99%

Simultaneous effect of temperature, shrinkage, and self-weight creep on RC beams: A case study

Aval

Ghabdian

Proceedings of the Institution of Mechanical Engineers, Part L:

et al. 2022

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This study presents the results of long-term field measurement of two RC beams under the simultaneous effect of medium to high temperature, shrinkage, and self-weight creep. In industrial complexes such as steel making plants, these members may, in addition to creep and shrinkage, be exposed to high temperature. However, less attention has been paid to the simultaneous effect of creep, shrinkage, and temperature in a case study framework. In this regard, two RC beams with the same geometric properties in a pelletizing plant located in Kerman, Iran, were studied. In addition, in order to establish a powerful numerical method for these effects, numerical results were compared with the field measurement data. The results showed that an average increase by 50% in temperature would increase the maximum deflection of RC beam by 37%. In the case of the environment temperature, grate machine temperature increased the maximum deflection of RC beam by 61%. Moreover, field measurements showed that for self-weight creep level, shrinkage, temperature, and cracking strains covered more than 80% of the total strain. Similarly, such as this case study, simultaneous effects of these triple factors can change the long-term serviceability of structural elements exposed to harsh environmental conditions.

“…Matrix Az(t) is replaced by a term f [z(t)] that considers both changing stiffness and damping properties of the system. The magnetic circuit has been studied to conclude that the "smart" base isolator can be adjusted when the system is subjected to an external uncertainty such as an earthquake [54][55][56]. Thus, an adaptive control law can be designed to meet the system uncertainty and the requirement of system adaptability.…”

Section: Rbf Based Adaptive Sliding Mode Controlmentioning

confidence: 99%

A Novel MRE Adaptive Seismic Isolator Using Curvelet Transform Identification

Altabey

et al. 2021

Applied Sciences

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Magnetorheological elastomeric (MRE) material is a novel type of material that can adaptively change the rheological property rapidly, continuously, and reversibly when subjected to real-time external magnetic field. These new type of MRE materials can be developed by employing various schemes, for instance by mixing carbon nanotubes or acetone contents during the curing process which produces functionalized multiwall carbon nanotubes (MWCNTs). In order to study the mechanical and magnetic effects of this material, for potential application in seismic isolation, in this paper, different mathematical models of magnetorheological elastomers are analyzed and modified based on the reported studies on traditional magnetorheological elastomer. In this regard, a new feature identification method, via utilizing curvelet analysis, is proposed to make a multi-scale constituent analysis and subsequently a comparison between magnetorheological elastomer nanocomposite and traditional magnetorheological elastomers in a microscopic level. Furthermore, by using this “smart” material as the laminated core structure of an adaptive base isolation system, magnetic circuit analysis is numerically conducted for both complete and incomplete designs. Magnetic distribution of different laminated magnetorheological layers is discussed when the isolator is under compressive preloading and lateral shear loading. For a proof of concept study, a scaled building structure is established with the proposed isolation device. The dynamic performance of this isolated structure is analyzed by using a newly developed reaching law sliding mode control and Radial Basis Function (RBF) adaptive sliding mode control schemes. Transmissibility of the structural system is evaluated to assess its adaptability, controllability and nonlinearity. As the findings in this study show, it is promising that the structure can achieve its optimal and adaptive performance by designing an isolator with this adaptive material whose magnetic and mechanical properties are functionally enhanced as compared with traditional isolation devices. The adaptive control algorithm presented in this research can transiently suppress and protect the structure against non-stationary disturbances in the real time.