Dynamic Characteristic of Axially Moving Soft Sandwich Beam

2013 ◽  
Vol 702 ◽  
pp. 275-279
Author(s):  
Hai Wei Lv ◽  
Ying Hui Li ◽  
Liang Li
Keyword(s):  
Governing Equation ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Soft Core ◽  
Independent Variables ◽  
The Third ◽  
Second Mode ◽  
Galerkin Truncation ◽  
Axially Moving ◽  
State Of Tension

A new sandwich beam theory is proposed by introducing independent variables of the displacements of face sheets, middle plane of soft core according to the incompression in transverse direction of traditional sandwich beam theory. Based on Hamilton principal, the governing equation of the system is established. Galerkin truncation method was used to solve the governing equation. It was found that (1) the first mode of the system displays that it is consistent with the traditional sandwich beam theory; (2) the second mode of the system shows that the soft core is in the state of tension or in compression; (3) the third mode of the system displays that the upper part and lower part of soft core are in different state (tension or compression); (4) The incompressible model of sandwich beam is the special form of soft sandwich beam we establish in this paper.

scholarly journals Transverse Vibrations and Stability of Axially Traveling Sandwich Beam With Soft Core

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Xiao-Dong Yang ◽  
Wei Zhang ◽  
Li-Qun Chen
Keyword(s):  
Critical Speed ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Axial Loading ◽  
Core Layer ◽  
Soft Core ◽  
Axially Moving Beam ◽  
Transverse Vibrations ◽  
Axially Moving ◽  
The Galerkin Method

The transverse vibrations and stability of an axially moving sandwich beam are studied in this investigation. The face layers are assumed to be in the membrane state, which bears only axial loading but no bending. Only shear deformation is considered for the soft core layer. The governing partial equation is derived using Newton's second law and then transferred into a dimensionless form. The Galerkin method and the complex mode method are employed to study the natural frequencies. In comparison with the classical homogenous axially moving beam, the gyroscopic matrix is no longer skew-symmetric because of the introduction of the soft core. The critical speed for the divergence of the axially moving sandwich beam is analytically obtained. The contribution of the core layer shear modulus to the natural frequencies and critical speed is discussed.

Is Thermal and Light-Induced Annealing of Met Astable Defects in a-Si:H Driven by Electrons?

1995 ◽  
Vol 377 ◽  
Author(s):  
Helena Gleskova ◽  
S. Wagner
Keyword(s):  
Electrical Conductivity ◽  
Light Intensity ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Free Electrons ◽  
Free Electron Density ◽  
Independent Variables ◽  
The Third ◽  
Defect Annealing ◽  
Hydrogenated Amorphous

ABSTRACTWe report results of a search for a unifying rate law for the annealing of metastable defects in hydrogenated amorphous silicon (a-Si:H). We tested the hypothesis that defect-annealing by both heating or illumination is driven by the density of free electrons. This hypothesis is formulated via the rate equation - dN/dt = A nα N f (T), where N is the defect density, t the time, A a constant, n the free electron density, and f (T) a function of temperature derived from a distribution of annealing energies. The model fits two sets of data, with light-intensity and electrical conductivity as the independent variables, reasonably well, with a ranging from 0.39 to 0.76, but not the third set, where we varied the temperature.

scholarly journals Changes in Incisor Third-Order Inclination Resulting from Vertical Variation in Lingual Bracket Placement

2009 ◽  
Vol 79 (4) ◽  
pp. 747-754 ◽  
Author(s):  
Michael Knösel ◽  
Klaus Jung ◽  
Liliam Gripp-Rudolph ◽  
Thomas Attin ◽  
Rengin Attin ◽  
...  
Keyword(s):  
Null Hypothesis ◽  
Interindividual Variation ◽  
Occlusal Plane ◽  
Third Order ◽  
Vertical Variation ◽  
Independent Variables ◽  
The Third ◽  
Dependent Variables ◽  
Incisor Inclination ◽  
The Impact

Abstract Objective: To test the null hypothesis that third-order measurements are not correlated to lingual incisor features seen on radiographs. Material and Methods: The lateral headfilms of 38 untreated, norm-occlusion subjects without incisor abrasions or restorations were used for third-order measurements of upper and lower central incisors and assessment of the inclination of four sites suitable for lingual bracket placement with reference to the occlusal plane perpendicular. Lingual sections were determined by the tangents at the incisal fossa (S1), at the transition plateau between incisal fossa and the cingulum (S2), by a constructed line reaching from the incisal tip to the cingulum (S3), and by a tangent at the cingulum convexity (S4). Third-order angles were also assessed on corresponding dental casts using an incisor inclination gauge. Regression analysis was performed using the third-order measurements of both methods as the dependent variables and the inclination of the lingual enamel sections (S1, S2, S3, S4) as the independent variables. Results: The null hypothesis was rejected. For the most common bracket application sites located on the lingual shovel (S1 and S2), third-order inclination changes of 0.4–0.7 degrees are expected for each degree of change in the inclination of the lingual surface. The impact of bracket placement errors on third-order angulation is similar between sections S1 and S2 and the cingulum convexity (S4). Section S3 proved to be least affected by interindividual variation. Conclusion: The third-order measurements are correlated to lingual incisor features. Accordingly, third-order changes resulting from variation in lingual bracket placement can be individually predicted from radiographic assessments.

scholarly journals Dynamic Analysis of Honeycomb Sandwich Beam with Multiple Debonds

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Saraswathy ◽  
R. Ramesh Kumar ◽  
Lalu Mangal
Keyword(s):  
Analytical Solution ◽  
Transient Analysis ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Beam Length ◽  
Honeycomb Core ◽  
Element Analysis ◽  
Fast Fourier Transform Analysis ◽  
Honeycomb Sandwich ◽  
Nonlinear Transient

Analytical formulation for the evaluation of frequency of CFRP sandwich beam with debond, following the split beam theory, generally underestimates the stiffness, as the contact between the honeycomb core and the skin during vibration is not considered in the region of debond. The validation of the present analytical solution for multiple-debond size is established through 3D finite element analysis, wherein geometry of honeycomb core is modeled as it is, with contact element introduced in the debond region. Nonlinear transient analysis is followed by fast Fourier transform analysis to obtain the frequency response functions. Frequencies are obtained for two types of model having single debond and double debond, at different spacing between them, with debond size up to 40% of beam length. The analytical solution is validated for a debond length of 15% of the beam length, and with the presence of two debonds of same size, the reduction in frequency with respect to that of an intact beam is the same as that of a single-debond case, when the debonds are well separated by three times the size of debond. It is also observed that a single long debond can result in significant reduction in the frequencies of the beam than multiple debond of comparable length.

Vibration Analysis of the Flexible Connecting Rod With the Breathing Crack in a Slider-Crank Mechanism

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Yan-Shin Shih ◽  
Chen-Yuan Chung
Keyword(s):  
Governing Equation ◽  
Moving Boundary ◽  
Beam Theory ◽  
Crack Model ◽  
Breathing Crack ◽  
Connecting Rod ◽  
Bernoulli Beam ◽  
The Galerkin Method ◽  
Euler Bernoulli Beam ◽  
Crank Mechanism

This paper investigates the dynamic response of the cracked and flexible connecting rod in a slider-crank mechanism. Using Euler–Bernoulli beam theory to model the connecting rod without a crack, the governing equation and boundary conditions of the rod's transverse vibration are derived through Hamilton's principle. The moving boundary constraint of the joint between the connecting rod and the slider is considered. After transforming variables and applying the Galerkin method, the governing equation without a crack is reduced to a time-dependent differential equation. After this, the stiffness without a crack is replaced by the stiffness with a crack in the equation. Then, the Runge–Kutta numerical method is applied to solve the transient amplitude of the cracked connecting rod. In addition, the breathing crack model is applied to discuss the behavior of vibration. The influence of cracks with different crack depths on natural frequencies and amplitudes is also discussed. The results of the proposed method agree with the experimental and numerical results available in the literature.

PENGARUH MOTIVASI, PENGAWASAN DAN BUDAYA KERJA TERHADAP PRODUKTIVITAS KERJA PEGAWAI KANTOR CAMAT LUENG BATA KOTA BANDA ACEH

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Erlinda ◽  
Lisda
Keyword(s):  
Work Productivity ◽  
Civil Servant ◽  
Research Problem ◽  
Linear Regression Method ◽  
Work Culture ◽  
Independent Variables ◽  
The Third ◽  
Multiple Linear Regression Method ◽  
Degree Of Confidence ◽  
Banda Aceh

The aim of this reseach is to find out the effect of motivation, supervision and work culture toward the productivity of civil servant sub-district head Lueng Bata Banda Aceh. The research problem is “how the motivation influence, supervision and work culture toward productivity of civil servant sub-district head Lueng Bata Banda Aceh district.To prove the hypothesis that is used multiple linear regression method with independent variables are motivation, supervision, work culture and the dependent variable is productivity and with degree of confidence 5%, the third of independent variables have influence significantly, either partial t-test or F-test. R2 value 0.727 that means 72,7% changing productivy can explain by contribution of  motivation variables, supervision and work culture toward the work productivity, and 27,3% can explain by other variables outside model. Keywords: motivation, supervision, culture work, productivity 

Determination of Instability Boundaries for a Highly Flexible Prismatic-Jointed Robot Performing Repetitive Maneuvers

1991 ◽  
Author(s):  
Keith W. Buffinton
Keyword(s):  
Floquet Theory ◽  
Equations Of Motion ◽  
Perturbation Techniques ◽  
Axial Motion ◽  
The Third ◽  
Straightforward Application ◽  
Method Yield ◽  
Robotic Devices ◽  
Axially Moving

Abstract Presented in this work are the equations of motion governing the behavior of a simple, highly flexible, prismatic-jointed robotic manipulator performing repetitive maneuvers. The robot is modeled as a uniform cantilever beam that is subject to harmonic axial motions over a single bilateral support. To conveniently and accurately predict motions that lead to unstable behavior, three methods are investigated for determining the boundaries of unstable regions in the parameter space defined by the amplitude and frequency of axial motion. The first method is based on a straightforward application of Floquet theory; the second makes use of the results of a perturbation analysis; and the third employs Bolotin’s infinite determinate method. Results indicate that both perturbation techniques and Bolotin’s method yield acceptably accurate results for only very small amplitudes of axial motion and that a direct application of Floquet theory, while computational expensive, is the most reliable way to ensure that all instability boundaries are correctly represented. These results are particularly relevant to the study of prismatic-jointed robotic devices that experience amplitudes of periodic motion that are a significant percentage of the length of the axially moving member.

Efficient Finite Element for Evaluation of Strain Concentrations in Concrete Coated Pipelines

2008 ◽  
Author(s):  
Svein Sævik ◽  
Martin Storheim ◽  
Erik Levold
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Material Model ◽  
Body Motion ◽  
Theoretical Formulation ◽  
Concrete Material ◽  
Non Linear ◽  
Full Scale Tests

MARINTEK has developed software for detailed analysis of pipelines during installation and operation. As part of the software development a new coating finite element was developed in cooperation with StatoilHydro enabling efficient analysis of field joint strain concentrations of long concrete coated pipeline sections. The element was formulated based on sandwich beam theory and application of the Principle of Potential Energy. Large deformations and non-linear geometry effects were handled by a Co-rotated “ghost” reference description where elimination of rigid body motion was taken care of by referring to relative displacements in the strain energy term. The non-linearity related to shear interaction and concrete material behaviour was handled by applying non-linear springs and a purpose made concrete material model. The paper describes the theoretical formulation and numerical studies carried out to verify the model. The numerical study included comparison between model and full-scale tests as well as between model and other commercial software. At last a 3000 m long pipeline was analysed to demonstrate the strain concentration behaviour of a concrete coated pipeline exposed to high temperature snaking on the seabed.

scholarly journals PENGARUH KINERJA KEUANGAN TERHADAP PEMBIAYAAN BANK UMUM SYARIAH DI INDONESIA (PERIODE 2009-2013)

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Irma Safitri ◽  
Nadirsyah Nadirsyah ◽  
Darwanis Darwanis
Keyword(s):  
Commercial Banks ◽  
Research Data ◽  
Capital Adequacy ◽  
Third Party ◽  
Islamic Banking ◽  
Islamic Banks ◽  
Independent Variables ◽  
The Third ◽  
Capital Adequacy Ratio ◽  
Observation Period

The purposes of this research were to determine the effect of the financial performance of Islamic commercial banks in Indonesia on financing, both individually and simultaneously. The performance was measured through Third Party Funds (TPF), Capital Adequacy Ratio (CAR), Non-Performing Financing (NPF), and Financing to Deposit Ratio (FDR). These four independent variables to be tested influence on the dependent variable. This research used census method that includes all of the Islamic banks in Indonesia for observational data. Research data observation period from 2009 until 2013 a total of 11 banks. Multiple linear regression was used to analyze the data.The results of this study found that the Third Party Funds (TPF), Capital Adequacy Ratio (CAR), Non Performing Financing (NPF), and Financing to Deposit Ratio (FDR) affect the financing, both individually and simultaneously. Fluctuations in either an increase or decrease of financing that occurred in Islamic banking in Indonesia is determined by the four independent variables. That is to say, the four independent variables that have an important role in the financing of Islamic banking in Indonesia. =========================================== Penelitian ini bertujuan untuk menguji pengaruh kinerja keuangan bank umum syariah di Indonesia terhadap pembiayaan, baik secara parsial maupun simultan. Kinerja keuangan diukur melalui Dana Pihak Ketiga (DPK), Capital Adequacy Ratio (CAR), Non Performing Financing (NPF), dan Financing to Deposit Ratio (FDR) Keempat variabel bebas tersebut akan diuji pengaruhnya terhadap satu variabel tidak bebas. Penelitian ini adalah penelitian sensus, yakni memasukan semua bank umum syariah yang ada di Indonesia ke dalam data pengamatan. Periode pengamatan data penelitian dari tahun 2009 s.d 2013 yang berjumlah 11 perbankan. Metode analisis yang digunakan adalah regresi linear berganda. Hasil penelitian ini menemukan bahwa Dana Pihak Ketiga (DPK), Capital Adequacy Ratio (CAR), Non Performing Financing (NPF), dan Financing to Deposit Ratio (FDR) berpengaruh terhadap pembiayaan pada perbankan syariah di Indonesia, baik secara parsial maupun simultan. Fluktuasi baik itu peningkatan atau penurunan pembiayaan yang terjadi pada perbankan syariah di Indonesia ditentukan oleh keempat variabel bebas tersebut. Sehingga dapat dikatakan bahwa, keempat variabel bebas tersebut mempunyai peranan penting atas pembiayaan pada perbankan syariah di Indonesia.

Edgewise Bending Vibration Analysis of a Rotating Sandwich Beam with Magnetorheological Elastomer Core

2018 ◽  
Vol 18 (11) ◽  
pp. 1850134 ◽  
Author(s):  
S. Bornassi ◽  
H. M. Navazi ◽  
H. Haddadpour
Keyword(s):  
Magnetic Field ◽  
Layer Thickness ◽  
Rectangular Cross Section ◽  
Ritz Method ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Core Layer ◽  
Magnetorheological Elastomer ◽  
Bending Vibration ◽  
Elastic Layers

The vibration of a rotating sandwich beam with magnetorheological elastomer (MRE) as a core between two elastic layers is theoretically analyzed in this paper. This study is focused on the bending vibration along the edgewise direction of a sandwich beam of rectangular cross-section, which, to the best of our knowledge, has not been addressed yet. The classical Euler–Bernoulli beam theory is used to model the dynamic behavior of the elastic layers. In the modeling, the effect of the MRE layer is considered by incorporating its shear strains and the inertia due to shear deformation and bending motion. The governing equations of motion of the rotating sandwich beam are derived by using the Ritz method and the Lagrange’s equations. The effects of the applied magnetic field, core layer thickness, rotational speed, setting angle and hub radius on the natural frequencies and the corresponding loss factors are investigated parametrically. The results show the significant effect of the magnetic field intensity and the MRE layer thickness on the modal characteristics of the MRE sandwich beam.

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