Active behavior of abdominal wall muscles: Experimental results and numerical model formulation

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

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Comparison between an Advanced Numerical Simulation of Sheet Incremental Forming Using Adaptive Remeshing and Experimental Results

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.554-557.1375 ◽

2013 ◽

Vol 554-557 ◽

pp. 1375-1381 ◽

Cited By ~ 5

Author(s):

Laurence Giraud-Moreau ◽

Abel Cherouat ◽

Jie Zhang ◽

Houman Borouchaki

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Sheet Metal ◽

Metal Forming ◽

Tool Path ◽

Incremental Forming ◽

Computation Time ◽

Experimental Results ◽

Forming Process ◽

Adaptive Remeshing

Recently, new sheet metal forming technique, incremental forming has been introduced. It is based on using a single spherical tool, which is moved along CNC controlled tool path. During the incremental forming process, the sheet blank is fixed in sheet holder. The tool follows a certain tool path and progressively deforms the sheet. Nowadays, numerical simulations of metal forming are widely used by industry to predict the geometry of the part, stresses and strain during the forming process. Because incremental forming is a dieless process, it is perfectly suited for prototyping and small volume production [1, 2]. On the other hand, this process is very slow and therefore it can only be used when a slow series production is required. As the sheet incremental forming process is an emerging process which has a high industrial interest, scientific efforts are required in order to optimize the process and to increase the knowledge of this process through experimental studies and the development of accurate simulation models. In this paper, a comparison between numerical simulation and experimental results is realized in order to assess the suitability of the numerical model. The experimental investigation is realized using a three-axis CNC milling machine. The forming tool consists in a cylindrical rotating punch with a hemispherical head. A subroutine has been developed to describe the tool path from CAM procedure. A numerical model has been developed to simulate the sheet incremental forming process. The finite element code Abaqus explicit has been used. The simulation of the incremental forming process stays a complex task and the computation time is often prohibitive for many reasons. During this simulation, the blank is deformed by a sequence of small increments that requires many numerical increments to be performed. Moreover, the size of the tool diameter is generally very small compared to the size of the metal sheet and thus the contact zone between the tool and the sheet is limited. As the tool deforms almost every part of the sheet, small elements are required everywhere in the sheet resulting in a very high computation time. In this paper, an adaptive remeshing method has been used to simulate the incremental forming process. This strategy, based on adaptive refinement and coarsening procedures avoids having an initially fine mesh, resulting in an enormous computing time. Experiments have been carried out using aluminum alloy sheets. The final geometrical shape and the thickness profile have been measured and compared with the numerical results. These measurements have allowed validating the proposed numerical model. References [1] M. Yamashita, M. Grotoh, S.-Y. Atsumi, Numerical simulation of incremental forming of sheet metal, J. Processing Technology, No. 199 (2008), p. 163 172. [2] C. Henrard, A.M. Hbraken, A. Szekeres, J.R. Duflou, S. He, P. Van Houtte, Comparison of FEM Simulations for the Incremental Forming Process, Advanced Materials Research, 6-8 (2005), p. 533-542.

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Numerical Simulation and Hydrodynamic Performance Predicting of 2 Two-Dimensional Hydrofoils in Tandem Configuration

Journal of Marine Science and Engineering ◽

10.3390/jmse9050462 ◽

2021 ◽

Vol 9 (5) ◽

pp. 462

Author(s):

Yuchen Shang ◽

Juan J. Horrillo

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Resource Constraints ◽

Lift Coefficient ◽

Parametric Method ◽

Experimental Results ◽

Hydrodynamic Performance ◽

Tandem Configuration ◽

Artificial Neural Network Ann ◽

Naca 0012

In this study we investigated the performance of NACA 0012 hydrofoils aligned in tandem using parametric method and Neural Networks. We use the 2D viscous numerical model (STAR-CCM+) to simulate the hydrofoil system. To validate the numerical model, we modeled a single NACA 0012 configuration and compared it to experimental results. Results are found in concordance with the published experimental results. Then two NACA 0012 hydrofoils in tandem configuration were studied in relation to 788 combinations of the following parameters: spacing between two hydrofoils, angle of attack (AOA) of upstream hydrofoil and AOA of downstream hydrofoil. The effects exerted by these three parameters on the hydrodynamic coefficients Lift coefficient (CL), Drag Coefficient (CD) and Lift-Drag Ratio (LDR), are consistent with the behavior of the system. To establish a control system for the hydrofoil craft, a timely analysis of the hydrodynamic system is needed due to the computational resource constraints, analysis of a large combination and time consuming of the three parameters established. To provide a broader and faster way to predict the hydrodynamic performance of two hydrofoils in tandem configuration, an optimal artificial neural network (ANN) was trained using the large combination of three parameters generated from the numerical simulations. Regression analysis of the output of ANN was performed, and the results are consistent with numerical simulation with a correlation coefficient greater than 99.99%. The optimized spacing of 6.6c are suggested where the system has the lowest CD while obtaining the highest CL and LDR. The formula of the ANN was then presented, providing a reliable predicting method of hydrofoils in tandem configuration.

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Numerical modeling of high velocity impact in sandwich panels with honeycomb core and composite skin including composite progressive damage model

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218817894 ◽

2018 ◽

Vol 22 (8) ◽

pp. 2768-2795 ◽

Cited By ~ 3

Author(s):

Meysam Khodaei ◽

Mojtaba Haghighi-Yazdi ◽

Majid Safarabadi

Keyword(s):

Numerical Model ◽

Sandwich Panel ◽

Material Model ◽

Absorption Capacity ◽

Numerical Results ◽

Ballistic Impact ◽

Experimental Results ◽

Ballistic Limit ◽

Honeycomb Core ◽

Damage Initiation

In this paper, a numerical model is developed to simulate the ballistic impact of a projectile on a sandwich panel with honeycomb core and composite skin. To this end, a suitable material model for the aluminum honeycomb core is used taking the strain-rate dependent properties into account. To validate the ballistic impact of the projectile on the honeycomb core, numerical results are compared with the experimental results available in literature and ballistic limit velocities are predicted with good accuracy. Moreover, to achieve composite skin material model, a VUMAT subroutine including damage initiation based on Hashin’s seven failure criteria and damage evolution based on MLT approach modulus degradation is used. To validate the composite material model VUMAT subroutine, the ballistic limit velocities of the projectile impact on the composite laminates are predicted similar to the numerical results presented by other researchers. Next, the numerical model of the sandwich panel ballistic impact at different velocities is compared with the available experimental results in literature, and energy absorption capacity of the sandwich panel is predicted accurately. In addition, the numerical model simulated the sandwich panel damage mechanisms in different stages similar to empirical observations. Also, the composite skin damages are investigated based on different criteria damage contours.

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PREDICTION OF WAVE FORCE ACTING ON HORIZONTAL PLATE

Coastal Engineering Proceedings ◽

10.9753/icce.v33.structures.52 ◽

2012 ◽

Vol 1 (33) ◽

pp. 52 ◽

Cited By ~ 3

Author(s):

Susumu Araki ◽

Ichiro Deguchi

Keyword(s):

Numerical Model ◽

Wave Force ◽

Experimental Results ◽

Prediction Methods ◽

Horizontal Plate

The applicability of the existing prediction methods of the wave force acting on a horizontal plate above the still water level is investigated by comparing the estimated wave force with the measured wave force. The applicability of a numerical model as well as the equations from experimental results is investigated. Some prediction methods overestimate the measured wave force, and some prediction methods underestimate the measured wave force.

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NUMERICAL MODEL OF BREAKWATER WAVE FLOWS

Coastal Engineering Proceedings ◽

10.9753/icce.v21.149 ◽

1988 ◽

Vol 1 (21) ◽

pp. 149 ◽

Cited By ~ 2

Author(s):

Alex C. Thompson

Keyword(s):

Mathematical Model ◽

Numerical Model ◽

Reflection Coefficient ◽

Water Wave ◽

Wave Equations ◽

Seepage Flow ◽

Experimental Results ◽

Simplified Model ◽

Flow Equations ◽

Shallow Water Wave Equations

A mathematical model of flow on a sloping breakwater face is described and results of calculations compared with some experimental results to show how the model can be calibrated. Flow above the surface of the slope is represented by the shallow water wave equations solved by a finite difference method. Flow within the breakwater is calculated by one of two methods. A solution of the linear seepage flow equations, again using finite differences or a simplified model of inflow can be used. Experimental results for runup and reflection coefficient are from tests performed at HRL Wallingford.

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Experimental-Numerical Design and Evaluation of a Vibration Bioreactor Using Piezoelectric Patches

Sensors ◽

10.3390/s19020436 ◽

2019 ◽

Vol 19 (2) ◽

pp. 436 ◽

Cited By ~ 2

Author(s):

David Valentín ◽

Charline Roehr ◽

Alexandre Presas ◽

Christian Heiss ◽

Eduard Egusquiza ◽

...

Keyword(s):

Numerical Model ◽

Mechanical Vibration ◽

Cell Types ◽

Experimental Results ◽

Cell Behavior ◽

Frequency Range ◽

Piezoelectric Patch ◽

Numerical Design ◽

Vibration Pattern

In this present study, we propose a method for exposing biological cells to mechanical vibration. The motive for our research was to design a bioreactor prototype in which in-depth in vitro studies about the influence of vibration on cells and their metabolism can be performed. The therapy of cancer or antibacterial measures are applications of interest. In addition, questions about the reaction of neurons to vibration are still largely unanswered. In our methodology, we used a piezoelectric patch (PZTp) for inducing mechanical vibration to the structure. To control the vibration amplitude, the structure could be excited at different frequency ranges, including resonance and non-resonance conditions. Experimental results show the vibration amplitudes expected for every frequency range tested, as well as the vibration pattern of those excitations. These are essential parameters to quantify the effect of vibration on cell behavior. Furthermore, a numerical model was validated with the experimental results presenting accurate results for the prediction of those parameters. With the calibrated numerical model, we will study in greater depth the effects of different vibration patterns for the abovementioned cell types.

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First Results of a 3D Pull-Out Model of Steel Anchors in Fired-Clay Bricks

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.817.514 ◽

2019 ◽

Vol 817 ◽

pp. 514-519 ◽

Cited By ~ 1

Author(s):

Francesco Finelli ◽

Angelo Di Tommaso ◽

Cristina Gentilini

Keyword(s):

Numerical Simulation ◽

Finite Element ◽

Numerical Model ◽

Experimental Results ◽

Clay Brick ◽

Finite Element Program ◽

Clay Bricks ◽

Pull Out ◽

First Results ◽

Element Program

The paper reports the results of a numerical simulation performed to study the experimental pull-out behavior of twisted steel connectors inserted in fired-clay brick units. The experimental results obtained in a previous campaign are used to calibrate a 3D refined numerical model developed by means of the finite element program Abaqus. The numerical model is tuned to accurately reproduce the experimental results in terms of loads and bar displacements.

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Numerical computation of wetting angles of Sn–(3−x)Ag–0.5Cu−x(Bi,In) quaternary Pb-free solder alloy systems on Cu substrate

International Journal of Modern Physics C ◽

10.1142/s0129183120501193 ◽

2020 ◽

Vol 31 (09) ◽

pp. 2050119

Author(s):

Ahmet Mustafa Erer ◽

Mukaddes Ökten Turacı

Keyword(s):

Numerical Model ◽

Numerical Computation ◽

Solder Alloy ◽

Empirical Model ◽

Sessile Drop ◽

Sessile Drop Method ◽

Experimental Results ◽

Cu Substrate ◽

Free Solder ◽

Alloy Systems

This paper was aimed to study of the wetting angle ([Formula: see text]) of Sn–Ag–Cu, Sn–([Formula: see text])Ag–0.5Cu–([Formula: see text])Bi and Sn–([Formula: see text])Ag–0.5Cu–([Formula: see text])In ([Formula: see text], 1 and 2 in wt.%) Pb-free solder alloy systems at various temperatures (250, 280 and 310∘C) on Cu substrate in Ar atmosphere. The new Sn–([Formula: see text])Ag–0.5Cu–xBi and Sn–([Formula: see text])Ag–0.5Cu[Formula: see text]([Formula: see text]) In systems, low Ag content quaternary Pb-free solder alloys, were produced by adding 0.5%, 1% and 2% Bi and In separately to the near-eutectic Sn-3[Formula: see text]wt.%Ag–0.5[Formula: see text]wt.%Cu (SAC305) alloy. The wetting angles of new alloys, Sn[Formula: see text]2.5[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]0.5[Formula: see text]wt.%Bi (SAC-0.5Bi), Sn[Formula: see text]2[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]1[Formula: see text]wt.%Bi(SAC-1Bi), Sn[Formula: see text]1[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]2[Formula: see text]wt.%Bi(SAC-2Bi), Sn[Formula: see text]2.5[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]0.5[Formula: see text]wt.%In (SAC-0.5In), Sn[Formula: see text]2[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]1[Formula: see text]wt.%In (SAC-1In) and Sn[Formula: see text]1[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt%.Cu[Formula: see text]2[Formula: see text]wt.%In (SAC-2In) were measured by sessile drop method. Experimental results showed that additions of Bi and In separately to SAC305 resulted in a continuous decrease in the [Formula: see text] up to 1[Formula: see text]wt.% above which the [Formula: see text] value was increased and it is appeared that a correlation among the [Formula: see text], alloys compositions and the test temperatures exists which recommended an empirical model to estimate the [Formula: see text] at a given Bi and In content and temperature for a given alloy systems. The numerical model estimates the [Formula: see text] understandably well with the present work.

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Numerical Simulation of the Added Mass of the Fluid Adjacent to the Ship Hull in Vibration Measured During Sea-Trials in Tanker Ships to be Converted to Offshore Construction Vessel

Volume 4: Offshore Geotechnics; Ronald W. Yeung Honoring Symposium on Offshore and Ship Hydrodynamics ◽

10.1115/omae2012-83964 ◽

2012 ◽

Author(s):

Severino Fonseca Silva Neto ◽

Silvia Ramscheid Figueiredo ◽

Marta Cecilia Tapia Reyes ◽

Luiza de Mesquita Ortiz

Keyword(s):

Numerical Model ◽

Kinetic Energy ◽

Natural Frequencies ◽

Three Dimensional ◽

Added Mass ◽

Vertical Vibration ◽

Full Scale ◽

Experimental Results ◽

Vibration Velocity ◽

Main Engine

This study aims to analyze the influence of the kinetic energy of the fluid adjacent to the hull of a tanker ship in its vertical vibration frequencies, comparing them with experimental measurements obtained during sea-trials. The one-dimensional modeling of ships allows the construction of simple finite element models from the structural elements of its master section, with structural and added masses, and their frequencies are verified by full-scale measurements, during the sea-trials. The numerical results of these models, with the value of the effective shear area as a fraction of the total area of the strength steel are compared to those obtained in full-scale measurements during sea trials of an oil tanker to be converted to Offshore Construction Vessel. Global vibration measurements were carried out in two of the six ships with the same hull. Accelerometers were installed in eleven strategic points of each hull. Vibration data acquisition was performed simultaneously for these locals in thirteen rotations of the main engine. The amplitude spectra of vibration velocity on the frequency range of measurements were obtained and were plotted graphs of the evolution of the main harmonics, depending on the rotation of the main engine, in order to identify four natural frequencies of the overall vibration of the hull, which were compared to the numerical model. The calculation is performed by the added mass formulations from Burrill, Todd, Kumay and Lewis/Landweber [8] curves, including in all three-dimensional effect by Townsin [17] coefficients, which is checked against the experimental results. The comparison between numerical and experimental results allows assessing the influence of the kinetic energy of the fluid surrounding the hull in the natural frequencies of vibration of the numerical model of the tanker ship and simulating their dynamic behavior after conversion in Offshore Construction Vessel.

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