Dynamic and Probabilistic Analysis of Shear Deformable Pipeline Resting on Two Parameter Foundation

The nonlinear dynamic deterministic and probabilistic analysis of pipeline undergoing large deflections and resting on Winkler-Pasternak foundation have been done. Dynamic analogues of Euler Bernoulli and Timoshenko Von-Kármán type beam equations are used. The stochastic finite element approach based on the Vanmarcke method combined to Monte Carlo simulations has been used to solve the governing nonlinear equations of soil-pipe interaction. The influence of different parameters of random soil is has been analyzed and the obtained results are compared with those obtained from the literature. It is concluded from the present work that the spatial variability of the soil properties has a great impact on the seismic response of the pipe and the developed model which is based on the accurate method is efficient to determine the real response of the safe and economic pipeline

Crack prediction in beam-like structure using ANN based on frequency analysis

The dynamic experimental and numerical analysis of cracked beams has been studied with the aim of quantifying the influence of depth crack on the dynamic response of steel beams. Artificial Neural Method ANN has been used where a numerical simulation was improved in Matlab. A finite element model has also been developed by using the Ansys software, and the obtained results were compared with exact crack length. The study takes into account different hidden layer values in order to determine the sensitivity of the predicted crack depth.  The results show that the response of the beam (frequencies) is strongly related to the crack depth which significantly affects the beam behavior, especially when the crack is very deep where the ANN allows us to identify the crack in lower computational time. Based on the provided results, we can detect that the effect of hidden layer size can affect the results. &nbsp

Modified Method for prefabricated vertical drain consolidation analysis

Ground improvement with the prefabricated vertical drain (PVD) has become widely employed for soft ground treatment because of its economical and efficient method. While numerous numerical and analytical methods have been derived for PVD however, it is still an extensively high demand for a simpler and more accurate method for design steps. This paper proposes a method for solving the problem of one-dimensional (1D) consolidation with prefabricated vertical drains. The current approach introduces a 1D equivalent permeability, increasing linearly with depth to perform the consolidation of soft ground improved with PVD. The analytical solutions have been carried out and verified by analyses for two cases of one-way drainage and two-way drainage for uniform soil layer. The results show that the error of excess pore pressure determined by the proposed method is less than that obtained by the simpler method of Chai and smaller than 10% compared to the theoretical solution. The paper also compares the analytical solution with the FEM by ABAQUS software. It is found that the excess pore pressures and consolidation degrees obtained by these methods are similar and close to the theory. These confirm that the introduced 1D equivalent permeability can be employed to perform the consolidation of PVD improvement by analytical and FEM methods

Modified Method for prefabricated vertical drain consolidation analysis

Ground improvement with the prefabricated vertical drain (PVD) has become widely employed for soft ground treatment because of its economical and efficient method. While numerous numerical and analytical methods have been derived for PVD however, it is still an extensively high demand for a simpler and more accurate method for design steps. This paper proposes a method for solving the problem of one-dimensional (1D) consolidation with prefabricated vertical drains. The current approach introduces a 1D equivalent permeability, increasing linearly with depth to perform the consolidation of soft ground improved with PVD. The analytical solutions have been carried out and verified by analyses for two cases of one-way drainage and two-way drainage for uniform soil layer. The results show that the error of excess pore pressure determined by the proposed method is less than that obtained by the simpler method of Chai and smaller than 10% compared to the theoretical solution. The paper also compares the analytical solution with the FEM by ABAQUS software. It is found that the excess pore pressures and consolidation degrees obtained by these methods are similar and close to the theory. These confirm that the introduced 1D equivalent permeability can be employed to perform the consolidation of PVD improvement by analytical and FEM methods

Crack prediction in pipeline using ANN-PSO based on numerical and experimental modal analysis

In this paper, a crack identification using Artificial Neural Network (ANN) is investigated to predict the crack depth in pipeline structure based on modal analysis technique using Finite Element Method (FEM). In various fields, ANN has become one of the most effective instruments using computational intelligence techniques to solve complex problems. This paper uses Particle Swarm Optimization (PSO) to enhance ANN training parameters (bias and weight) by minimizing the difference between actual and desired outputs and then using these parameters to generate the network. The convergence study during the process proves the advantage of using PSO based on two selected parameters. The data are collected from FEM based on different crack depths and locations. The provided technique is validated after collecting the data from experimental modal analysis. To study the effectiveness of ANN-PSO, different hidden layers values are considered to study the sensitivity of the predicted crack depth. The results demonstrate that ANN combined with PSO (ANN-PSO) is accurate and requires a lower computational time in terms of crack identification based on inverse problem

Crack prediction in beam-like structure using ANN based on frequency analysis

The dynamic experimental and numerical analysis of cracked beams has been studied with the aim of quantifying the influence of depth crack on the dynamic response of steel beams. Artificial Neural Method ANN has been used where a numerical simulation was improved in Matlab. A finite element model has also been developed by using the Ansys software, and the obtained results were compared with exact crack length. The study takes into account different hidden layer values in order to determine the sensitivity of the predicted crack depth. The results show that the response of the beam (frequencies) is strongly related to the crack depth, which significantly affects the beam behavior, especially when the crack is very deep where the ANN allows us to identify the crack in lower computational time. Based on the provided results, we can detect that the effect of hidden layer size can affect the results

Experimental and numerical vibration analyses of healthy and cracked pipes

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