Dynamic Stress Analysis of Exposed Pipes Subjected to a Moving In-line Inspection Tool

2020 ◽  
pp. 1-35
Author(s):  
Hamid Mostaghimi ◽  
Mohsen Hassani ◽  
Deli Yu ◽  
Ronald J. Hugo ◽  
Simon S. Park
Keyword(s):  
Dynamic Stress ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Assessment Method ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Pipe Section ◽  
Proposed Model ◽  
Wide Range

Abstract In-line inspection (ILI) is a non-destructive assessment method commonly used for defect assessment and for pipeline monitoring. Passing an ILI tool through an excavated or exposed section of a pipe during an integrity assessment can excite vibrations. The ILI tool's weight and speed can exert substantial forces, stresses, and deflections on the pipe section. When the excitation frequency from the ILI tool's movement is close to the pipe's natural frequency, the dynamic stress generated within the pipe can become great enough that it creates integrity concerns on the pipeline. This research aims to study effects of an ILI tool's passage through exposed and partially supported pipes under a variety of boundary and loading conditions. A finite element model of an exposed pipe section is developed based on the Timoshenko beam theory to predict the pipe's displacement, strain, stress, and frequency responses under a wide range of excitation frequencies. The model is further validated using a lab-scale experimental setup with a mass that moves at different speeds. A comparison between the simulation and the experimental results shows that the proposed model can effectively predict the pipe's dynamics.

Dynamic Stress Analysis of Exposed Pipes Subjected to Moving In-Line Inspection Tool

2020 ◽  
Author(s):  
Hamid Mostaghimi ◽  
Mohsen Hassani ◽  
Deli Yu ◽  
Ron Hugo ◽  
Simon Park
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Stress ◽  
Equations Of Motion ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Assessment Method ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Proposed Model ◽  
Assessment And Monitoring

Abstract In-line inspection is a non-destructive assessment method commonly used for defect assessment and monitoring of pipelines. The passage of an ILI tool through an excavated or exposed section of a pipe during an integrity assessment can excite vibrations and exert substantial forces, stress, and deflections on the pipe due to the weight and speed of the ILI tool. When the excitation frequency due to the ILI tool movement is close to the natural frequency of the overall structure, the dynamic stress generated within the pipe can be large enough to the extent that it imposes integrity concern on the line. This research aims to study effects of the ILI tool passage through floating and partially supported pipes under a variety of boundary and loading conditions. A finite element method is used to model the pipe with moving ILI tool. The model is developed based on Timoshenko beam theory with planar degrees-of-freedom and the differential equations of motion are solved numerically to predict displacement, strain, stress, and frequency responses of the pipe. The model is further validated using a lab-scale experimental setup. The comparison of the simulation to experimental results show how the proposed model is capable of predicting pipe dynamics, effectively.

Electrothermally Tunable Bridge Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Nouha Alcheikh ◽  
Abdallah Ramini ◽  
Md Abdullah Al Hafiz ◽  
Mohammad I. Younis
Keyword(s):  
Fundamental Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Bernoulli Beam ◽  
Electrothermal Actuation ◽  
Wide Range ◽  
Simulation Results ◽  
Dc Current ◽  
Euler Bernoulli Beam ◽  
Good Agreement

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

Highly Tunable Electrothermally Actuated Arch Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Abdallah Ramini ◽  
Nouha Alcheikh ◽  
Mohammad I. Younis
Keyword(s):  
Resonance Frequency ◽  
Axial Stress ◽  
Beam Theory ◽  
Element Model ◽  
Shallow Arches ◽  
Tunable Resonators ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Euler Bernoulli Beam ◽  
Thermal Voltage

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated MEMS arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and results of a multi-physics finite-element model. A good agreement is found among all the results. The electrothermal voltage is applied between the anchors of the clamped-clamped MEMS arch beam, generating a current that passes through the MEMS arch beam and controls its axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to increase in its curvature, thereby increases the resonance frequencies of the structure. We show here that the first resonance frequency can increase up to twice its initial value. We show also that after some electro-thermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators.

scholarly journals Numerical Analysis for U-Shaped Thin-Walled Structure Reinforced Timber Beam Based on Thin-Layer Beam Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Hui Liu ◽  
Jun Hu ◽  
Guohui Li ◽  
Guangying Mo
Keyword(s):  
Thin Layer ◽  
Beam Theory ◽  
Accurate Solution ◽  
Alloy Sheet ◽  
Element Analysis ◽  
Rational Engineering ◽  
Proposed Model ◽  
Wide Range ◽  
Thin Walled ◽  
Beam Height

This paper presents a theoretical model, taking into account the shear deformation subjected to the influence of U-shaped member by geometric parameters as flange height based on thin-layer beam theory, to analyze the structural bending behavior of U-shaped member reinforced timber composite beams, and the feasible design forms of U-section have been pointed out. The algorithm for this composite beam is the most practical and effective method to meet the accurate solution. The formulas for the common forms of U-section are presented. It aims to develop a rational engineering approach. The proposed model has been validated by comparing the results obtained in the present analysis with experimental results and finite element analysis. Furthermore, the results suggested that the value of flange height can be one-fifth the beam height based on the present analysis by comparison of two types of beams. And it is shown that the model provided here correlates consistently and satisfactorily with a wide range of timber beams reinforced by a thin-walled structure such as steel or aluminum alloy sheet bonded to their tension faces.

A new hysteresis model for magneto–rheological dampers based on Magic Formula

2020 ◽  
pp. 095440622095488
Author(s):  
Quoc–Duy Bui ◽  
Quoc Hung Nguyen ◽  
Xian–Xu ‘Frank’ Bai ◽  
Duc–Dai Mai
Keyword(s):  
Excitation Frequency ◽  
Model Parameters ◽  
Magic Formula ◽  
Hysteresis Behavior ◽  
Hysteresis Curves ◽  
Mr Dampers ◽  
Nonlinear Hysteresis ◽  
Proposed Model ◽  
Wide Range ◽  
Magneto Rheological

This paper investigates a novel model based on the Magic Formula and the Pan’s model to effectively predict the inherent nonlinear hysteresis behavior of magneto–rheological (MR) dampers. In the proposed model, the hysteresis element is employed from the Magic Formula and Pan’s model, and two new independent horizontal shift parameters, which are separated from one original parameter of the Pan’s model, are added. Each of them characterizes an offset with respect to the origin for each branch of hysteresis curves, providing more flexibility and effectiveness for simulating curves with high asymmetry. In addition, a parameter to further control the sharpness of hysteresis curves in the backward region of damping force–velocity is proposed, which is useful to simulate the behavior of MR dampers in rather extreme operating cases. A case study is performed on a prototype MR damper for washing machines, in which the model incorporates applied current and excitation frequency as variables to make it more adaptable to a wide range of working conditions. For comparison, performance of three hysteresis models, including the Spencer’s model, the Pan’s model and the proposed model, are analyzed and evaluated. The research results show that, as compared with the others, the proposed model can not only predict the nonlinear hysteresis behavior of MR dampers more precisely, but is also more compatible with different operating excitations, and the clearer meanings of the model parameters make them easier to study and identify.

scholarly journals Modified Numerical Modeling of Axially Loaded Concrete-Filled Steel Circular-Tube Columns

2021 ◽  
Vol 11 (3) ◽  
pp. 7094-7099
Author(s):  
P. C. Nguyen ◽  
D. D. Pham ◽  
T. T. Tran ◽  
T. Nghia-Nguyen
Keyword(s):  
Circular Tube ◽  
Experimental Tests ◽  
Element Model ◽  
Modified Model ◽  
Proposed Model ◽  
Wide Range ◽  
Strain Relationship ◽  
Concrete Damaged Plasticity ◽  
Cfst Columns ◽  
Good Agreement

Predicting the behavior of concrete in a Concrete-Filled Steel Tubular (CFST) column is challenging due to the sensitivity to input parameters such as the size of the cross-section, the material modeling, and the boundary conditions. The present paper proposes a new modified finite element model to predict the behavior and strength of a CFST subjected to axial compression. The development is based on the concrete damaged plasticity model, with its stress-strain relationship revised from the available model. The predicted accuracy of the modified model is verified via a wide range of experimental tests. The proposed model has more accuracy than the available models in predicting the ultimate compression strength. The results show good agreement with the test data, allowing its use in modeling CFST columns.

Forced Vibration of Overhead Transmission Line: Analytical and Experimental Investigation

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
O. Barry ◽  
J. W. Zu ◽  
D. C. D. Oguamanam
Keyword(s):  
Transmission Line ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Overhead Transmission Line ◽  
Proposed Model ◽  
Parametric Studies ◽  
Tip Mass ◽  
Euler Bernoulli Beam ◽  
Stockbridge Damper

An analytical model of a single line transmission line carrying a Stockbridge damper is developed based on the Euler–Bernoulli beam theory. The conductor is modeled as an axially loaded beam and the messenger is represented as a beam with a tip mass at each end. Experiments are conducted to validate the proposed model. An explicit expression is presented for the damping ratio of the conductor. Numerical examples show that the proposed model is more accurate than the models found in the literature. Parametric studies indicate that the response of the conductor significantly depends on the excitation frequency, the location of the damper, and the damper parameters.

scholarly journals On Modeling the Bending Stiffness of Thin Semi-Circular Flexure Hinges for Precision Applications

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 86 ◽  
Author(s):  
Mario Torres Melgarejo ◽  
Maximilian Darnieder ◽  
Sebastian Linß ◽  
Lena Zentner ◽  
Thomas Fröhlich ◽  
...  
Keyword(s):  
Finite Element ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Bending Stiffness ◽  
Analytical Models ◽  
Element Analysis ◽  
Flexure Hinges ◽  
Wide Range

Compliant mechanisms based on flexure hinges are widely used in precision engineering applications. Among those are devices such as precision balances and mass comparators with achievable resolutions and uncertainties in the nano-newton range. The exact knowledge of the mechanical properties of notch hinges and their modeling is essential for the design and the goal-oriented adjustment of these devices. It is shown in this article that many analytical equations available in the literature for calculating the bending stiffness of thin semi-circular flexure hinges cause deviations of up to 12% compared to simulation results based on the three-dimensional finite element model for the considered parameter range. A close examination of the stress state within the loaded hinge reveals possible reasons for this deviation. The article explains this phenomenon in detail and shows the limitations of existing analytical models depending on specific geometric ratios. An accurate determination of the bending stiffness of semi-circular flexure hinges in a wide range of geometric parameters without the need for an elaborate finite element analysis is proposed in form of FEM-based correction factors for analytical equations referring to Euler-Bernoulli’s beam theory.

scholarly journals Review of the Upright Balance Assessment Based on the Force Plate

2021 ◽  
Vol 18 (5) ◽  
pp. 2696
Author(s):  
Baoliang Chen ◽  
Peng Liu ◽  
Feiyun Xiao ◽  
Zhengshi Liu ◽  
Yong Wang
Keyword(s):  
Postural Balance ◽  
Force Plate ◽  
Assessment Method ◽  
Balance Assessment ◽  
Experimental Conditions ◽  
Methodological Research ◽  
Assessment Tests ◽  
Wide Range ◽  
Foot Posture ◽  
Plate System

Quantitative assessment is crucial for the evaluation of human postural balance. The force plate system is the key quantitative balance assessment method. The purpose of this study is to review the important concepts in balance assessment and analyze the experimental conditions, parameter variables, and application scope based on force plate technology. As there is a wide range of balance assessment tests and a variety of commercial force plate systems to choose from, there is room for further improvement of the test details and evaluation variables of the balance assessment. The recommendations presented in this article are the foundation and key part of the postural balance assessment; these recommendations focus on the type of force plate, the subject’s foot posture, and the choice of assessment variables, which further enriches the content of posturography. In order to promote a more reasonable balance assessment method based on force plates, further methodological research and a stronger consensus are still needed.

scholarly journals Prediction of Dead Oil Viscosity: Machine Learning vs. Classical Correlations

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 930
Author(s):  
Fahimeh Hadavimoghaddam ◽  
Mehdi Ostadhassan ◽  
Ehsan Heidaryan ◽  
Mohammad Ali Sadri ◽  
Inna Chapanova ◽  
...  
Keyword(s):  
Machine Learning ◽  
Viscosity Data ◽  
Oil Viscosity ◽  
Pvt Data ◽  
Proposed Model ◽  
Wide Range ◽  
Engineering Problems ◽  
Functional Forms ◽  
Insight Into

Dead oil viscosity is a critical parameter to solve numerous reservoir engineering problems and one of the most unreliable properties to predict with classical black oil correlations. Determination of dead oil viscosity by experiments is expensive and time-consuming, which means developing an accurate and quick prediction model is required. This paper implements six machine learning models: random forest (RF), lightgbm, XGBoost, multilayer perceptron (MLP) neural network, stochastic real-valued (SRV) and SuperLearner to predict dead oil viscosity. More than 2000 pressure–volume–temperature (PVT) data were used for developing and testing these models. A huge range of viscosity data were used, from light intermediate to heavy oil. In this study, we give insight into the performance of different functional forms that have been used in the literature to formulate dead oil viscosity. The results show that the functional form f(γAPI,T), has the best performance, and additional correlating parameters might be unnecessary. Furthermore, SuperLearner outperformed other machine learning (ML) algorithms as well as common correlations that are based on the metric analysis. The SuperLearner model can potentially replace the empirical models for viscosity predictions on a wide range of viscosities (any oil type). Ultimately, the proposed model is capable of simulating the true physical trend of the dead oil viscosity with variations of oil API gravity, temperature and shear rate.

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