scholarly journals A Harbor Resonance Numerical Model with Reflecting, Absorbing and Transmitting Boundaries

2017 ◽  
Vol 11 (1) ◽  
pp. 413-432 ◽  
Author(s):  
Yansheng Chang ◽  
Edward H. Wang
Keyword(s):  
Finite Element ◽  
Wave Equation ◽  
Numerical Model ◽  
Wave Amplitude ◽  
Bottom Friction ◽  
Wave Transmission ◽  
Conservation Of Energy ◽  
Harbor Resonance ◽  
Wave Refraction ◽  
Absorbing Boundaries

Background: A very important aspect in the planning and design of a harbor is to determine the response of the harbor basin to incident waves. Many previous investigators have studied various aspects of the harbor resonance problem, though correct to a certain extent, have some disadvantages. Objective: To calculate wave response in an offshore or coastal harbor of arbitrary shape, this research develops a two-dimensional linear, inviscid, dispersive, hybrid finite element harbor resonance model using conservation of energy approach. Based on the mild-slope wave equation, the numerical model includes wave refraction, diffraction, and reflection. The model also incorporates the effects of variable bathymetry, bottom friction, variable, full or partial absorbing boundaries, and wave transmission through permeable breakwaters. Methods: Based on the mild-slope wave equation, the numerical model includes wave refraction, diffraction, and reflection. The model also incorporates the effects of variable bathymetry, bottom friction, variable, full or partial absorbing boundaries, and wave transmission through permeable breakwaters. The Galerkin finite element method is used to solve the functional which was obtained using the governing equations. This model solves both long-waves as well as short-wave problems. The accuracy and efficiency of the present model are verified by comparing different cases of rectangular harbor numerical results with analytical and experimental results. Results: There said results indicate that reduction in wave amplitude inside a harbor caused by energy dissipation due to water depth, linearly sloping bottom, and bottom friction is quite small for a deep harbor. But for a shallow harbor, these factors are critical. They also show that reduction in wave amplitude inside a harbor due to boundary absorption, permeable transmission, harbor entrance width, and horizontal dimensions. Conclusion: Those factors are very important for both deep and shallow harbors as proven by accurate agreement with the prediction of this numerical model. The model presented herein is a realistic method for solving harbor resonance problems.

Finite Element Analysis of the Distributed Vibration Absorbers for Structural Noise Control

2005 ◽  
Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Base Plate ◽  
Element Model ◽  
Fe Model ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Poroelastic Media ◽  
Hexahedral Elements ◽  
Component Models

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

scholarly journals Numerical model of the nanoindentation test based on the digital material representation of the Ti/TiN multilayers

2015 ◽  
Vol 33 (2) ◽  
pp. 348-355 ◽  
Author(s):  
Konrad Perzyński ◽  
Radosław Wiatr ◽  
Łukasz Madej
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Cellular Automata ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Nanoindentation Test ◽  
Cellular Automata Model ◽  
Finite Element Software ◽  
Specific Morphology ◽  
Digital Material

AbstractThe developed numerical model of a local nanoindentation test, based on the digital material representation (DMR) concept, has been presented within the paper. First, an efficient algorithm describing the pulsed laser deposition (PLD) process was proposed to realistically recreate the specific morphology of a nanolayered material in an explicit manner. The nanolayered Ti/TiN composite was selected for the investigation. Details of the developed cellular automata model of the PLD process were presented and discussed. Then, the Ti/TiN DMR was incorporated into the finite element software and numerical model of the nanoindentation test was established. Finally, examples of obtained results presenting capabilities of the proposed approach were highlighted.

Physical statement of the problem for a numerical model of soil freezing and heaving taking into account heat and mass transfer

2021 ◽  
pp. 244-256
Author(s):  
Виктор Григорьевич Чеверев ◽  
Евгений Викторович Сафронов ◽  
Алексей Александрович Коротков ◽  
Александр Сергеевич Чернятин
Keyword(s):  
Finite Element Method ◽  
Mass Transfer ◽  
Finite Element ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Heat And Mass Transfer ◽  
Soil Freezing ◽  
The Finite Element Method ◽  
Freezing Front ◽  
Element Method

Существуют два основных подхода решения задачи тепломассопереноса при численном моделировании промерзания грунтов: 1) решение методом конечных разностей с учетом граничных условий (границей, например, является фронт промерзания); 2) решение методом конечных элементов без учета границ модели. Оба подхода имеют существенные недостатки, что оставляет проблему решения задачи для численной модели промерзания грунтов острой и актуальной. В данной работе представлена физическая постановка промерзания, которая позволяет создать численную модель, базирующуюся на решении методом конечных элементов, но при этом отражающую ход фронта промерзания - то есть модель, в которой объединены оба подхода к решению задачи промерзания грунтов. Для подтверждения корректности модели был проделан ряд экспериментов по физическому моделированию промерзания модельного грунта и выполнен сравнительный анализ полученных экспериментальных данных и результатов расчетов на базе представленной численной модели с такими же граничными условиями, как в экспериментах. There are two basic approaches to solving the problem of heat and mass transfer in the numerical modeling of soil freezing: 1) using the finite difference method taking into account boundary conditions (the boundary, for example, is the freezing front); 2) using the finite element method without consideration of model boundaries. Both approaches have significant drawbacks, which leaves the issue of solving the problem for the numerical model of soil freezing acute and up-to-date. This article provides the physical setting of freezing that allows us to create a numerical model based on the solution by the finite element method, but at the same time reflecting the route of the freezing front, i.e. the model that combines both approaches to solving the problem of soil freezing. In order to confirm the correctness of the model, a number of experiments on physical modeling of model soil freezing have been performed, and a comparative analysis of the experimental data obtained and the calculation results based on the provided numerical model with the same boundary conditions as in the experiments was performed.

Stress in Bonded Adherends for Single Lap Joints

1996 ◽  
Vol 12 (03) ◽  
pp. 167-171
Author(s):  
G. Bezine ◽  
A. Roy ◽  
A. Vinet
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Numerical Model ◽  
Stress Distribution ◽  
Normal Stress ◽  
Lap Joints ◽  
Axial Loads ◽  
Normal Stress Distribution ◽  
Single Lap Joints ◽  
Element Technique

A finite-element technique is used to predict the shear stress and normal stress distribution in adherends for polycarbonate/polycarbonate single lap joints subjected to axial loads. Numerical and photoelastic results are compared so that a validation of the numerical model is obtained. The influences on stresses of the overlap length and the shape of the adherends are studied.

scholarly journals Verification of the flexion and shear behavior in masonry panels accordance to ABNT NBR 15961-1 (2011), EN 1996-1-1 (2005) and ACI TMS 530 (2013)

2018 ◽  
Vol 11 (4) ◽  
pp. 673-685
Author(s):  
R. C. MATA ◽  
C. S. RAMOS ◽  
M. L. C. SILVA
Keyword(s):  
Computer Simulation ◽  
Finite Element ◽  
Numerical Model ◽  
Design Criteria ◽  
Two Dimensional ◽  
Finite Element Software ◽  
Modelling Procedure ◽  
Increasing Trend ◽  
American Standard ◽  
Compression Level

Abstract This paper presents a numerical analysis of the mechanical behavior of structural masonry panels submitted to horizontal and vertical stresses. To evaluate the design process of these structures, the results obtained by the computer simulations were compared with the results determined by the design criteria of ABNT NBR 15961-1 (2011), ACI TMS 530 (2013) and EN 1996-1-1 (2005). The finite element software DIANA v.9.3 was used to simulate two-dimensional models with the simplified micro modelling procedure. The results obtained by the normative standards were more conservative than the results of the numerical model, as expected. With the increase of the pre-compression level, the computer simulation has demonstrated the increasing trend of the values of resistant forces, besides the change of the way of rupture of the panels. Among the three standards evaluated, the American Standard was the most conservative.

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