Analytical Model of a Simple Supported Beam with Variable Section Subjected by a Moving Load

2011 ◽  
Vol 291-294 ◽  
pp. 1535-1538 ◽  
Author(s):  
Jun Zhang ◽  
Zi Wen Zhou ◽  
Jin Xv ◽  
Xiao Lu Ni
Keyword(s):  
Analytical Model ◽  
Analytical Approach ◽  
Maximum Stress ◽  
Moving Load ◽  
Numerical Approach ◽  
Newmark Method ◽  
Concentrated Force ◽  
Model Method ◽  
Variable Section ◽  
Constant Section

The variable section influence on the vibration of a simple supported beam under the action of a moving constant concentrated force is investigated in this work. The technique is based on analytical approach with the assumed model method and the numerical approach of Newmark method. Comparisons with the results between vary-section beam and constant-section one indicate that it is a wise approach to economizing materials and lightening the load of gravity by applying vary-section beam on the condition that the maximum stress cannot change dramatically.

Analytical evaluation of track response in the vertical direction due to a moving load

2016 ◽  
Vol 23 (18) ◽  
pp. 2989-3006 ◽  
Author(s):  
Wlodzimierz Czyczula ◽  
Piotr Koziol ◽  
Dariusz Kudla ◽  
Sergiusz Lisowski
Keyword(s):  
Steady State ◽  
Moving Load ◽  
Vertical Direction ◽  
Vertical Displacement ◽  
Steady State Response ◽  
Concentrated Force ◽  
State Response ◽  
Weakly Coupled ◽  
Wide Range ◽  
Rail Deflection

In the literature, typical analytical track response models are composed of beams (which represent the rail) on viscoelastic or elastic foundations. The load is usually considered as a single concentrated force (constant or varying in time) moving with constant speed. Concentrated or distributed loads or multilayer track models have rarely been considered. One can find some interesting results concerning analysis of distributed loads and multilayer track structures that include both analytical and numerical approaches. However, there is a noticeable lack of sufficient comparison between track responses under concentrated or distributed load and between one and multilayer track models. One of the unique features of the present paper is a comparison of data obtained for a series of concentrated and distributed loads, which takes into account a wide range of track parameters and train speeds. One of the fundamental questions associated with the multilayer track model is the level of coupling between the rail and the vibrations of the sleepers. In this paper, it is proved that sleepers are weakly coupled with the rail if the track is without significant imperfections, and the steady-state response is analyzed for this case. In other words, sleeper vibrations do not influence the rail vibrations significantly. Therefore the track is analyzed by means of a two-stage model. The first step of this model determines rail vibration under a moving load, and then the sleeper vibration is calculated from previously obtained kinematic excitation. The model is verified by comparison of the obtained results with experimental data. Techniques based on Fourier series are applied to the solution of the steady-state track response. Another important problem associated with track response under moving loads arises from the analysis of the effect of longitudinal forces in rails on vertical displacement. It is shown that, in the case of the steady-state response, longitudinal forces do not influence rail displacements significantly and this observation remains correct for a wide range of track parameters and train speeds. The paper also analyzes the legitimacy of the statement that additional rail deflection between sleepers, compared to the continuous rail support, can be considered as a track imperfection.

Analytical Model Method for Dynamics of N-Celled Tetrahedron-Tetrahedron Variable Geometry Truss Manipulators

1998 ◽  
Author(s):  
Li Ju Xu ◽  
Hong Li ◽  
Shou Wen Fan
Keyword(s):  
Analytical Model ◽  
Variable Geometry ◽  
Symbolic Form ◽  
Model Method ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

Abstract In this paper some fundamental formulae are derived for tetrahedron-based variable geometry truss manipulator which is composed of a series of tetrahedrons stacked upon each other such that one link in each cell is made variable on length. Analytical model for dynamics of the manipulator is established, and expressions in numeric-symbolic form of model matrices are derived. An example is given for illustration.

Potenziale der Mehrmaschinenbedienung*/Potentials of multiple-machine operation

2016 ◽  
Vol 106 (04) ◽  
pp. 211-217
Author(s):  
M. Thurm ◽  
S. Horler ◽  
D. Oehme ◽  
A. Opitz ◽  
E. Prof. Müller
Keyword(s):  
Analytical Model ◽  
Production System ◽  
Analytical Approach ◽  
Software Tool ◽  
New Approach ◽  
Machine Operation ◽  
Resource Input

Die prozess- und kostenorientierte Auslegung der Mehrmaschinenbedienung soll mithilfe eines neuen analytischen Modellansatzes die Ressourcennutzung effizienter gestalten. Dabei steht die Integration von Mitarbeiterqualifikation und Maschinenpriorität im Fokus. Durch die später geplante Implementierung des neu entwickelten Ansatzes in das Softwaretool SmartPlanner der CAPPcore GmbH gelingt es, die Planung und Optimierung von Produktionssystemen zu verbessern.   A new approach for process and cost-related designing of multiplemachine operation is developed to optimize the resource input. Skills of employees and priority of machines have to be considered in the analytical model. The new analytical approach of multiple machine operation will be integrated in the software tool Smart Planner of the enterprise CAPPcore GmbH later on to improve the planning and optimization of the production system as a whole.

scholarly journals Nonlinear Analysis of Steel Structure Bent Frame Column Bearing Transverse Concentrated Force at the Top in Factory Buildings

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1664
Author(s):  
Chunbao Li ◽  
Lina Wang ◽  
Yongmei Weng ◽  
Pengju Qin ◽  
Gaojie Li
Keyword(s):  
Spatial Structure ◽  
Nonlinear Analysis ◽  
Bending Moment ◽  
Steel Structure ◽  
Frame Structure ◽  
Theoretical Formula ◽  
Ansys Software ◽  
Concentrated Force ◽  
Variable Section ◽  
Factory Building

The steel bent frame structure of single-story factory buildings is actually a spatial structure system. Different bent frame columns are connected with the roof of bent frame structure, making the columns work and bearing the load together. In the steel frame of the factory building with bridge cranes below 20 t, variable-section columns with corbels are used to bear the crane load. In this article, the steel bent frame column of single-story factory buildings was taken as the research object. The bent frame column was simplified as a cantilever variable stepped column bearing a transverse concentrated force at the top. After simplifying the model, the theoretical formula of deflection, rotating angle, and bending moment of the compression rod was put forward. Moreover, bending deformation and stability of variable stepped columns were analyzed in order to obtain the theoretical and practical formula, then the ANSYS software was used to simulate the bent column.

scholarly journals Suppression of Ground Borne Vibration Induced by High-Speed Lines

2018 ◽  
Vol 152 ◽  
pp. 02001
Author(s):  
Ali Mohamed Rathiu ◽  
Mohammad Hosseini Fouladi ◽  
Satesh Narayana Namasivayam ◽  
Hasina Mamtaz
Keyword(s):  
Mathematical Model ◽  
Analytical Model ◽  
High Speed ◽  
Moving Load ◽  
Ground Vibration ◽  
Harmonic Excitation ◽  
Vibration Response ◽  
Vibration Velocity ◽  
Velocity Response ◽  
The Mathematical Model

Vibration of high-speed lines leads to annoyance of public and lowering real estate values near the railway lines. This hinders the development of railway infrastructures in urbanised areas. This paper investigates the vibration response of an isolated rail embankment system and modifies the component to better attenuate ground vibration. Mainly velocity response is used to compare the responses and the applied force is of 20 kN at excitation frequencies of 5.6 Hz and 8.3 Hz. Focus was made on ground-borne vibration and between the frequency range of 0 and 250 Hz. 3D Numerical model was made using SolidWork software and frequency response was produced using Harmonic Analysis module from ANSYS Workbench software. For analytical modelling MATLAB was used along with Simulink to verify the mathematical model. This paper also compares the vibration velocity decibels (VdB) of analytical two-degree of freedom model mathematical model with literature data. Harmonic excitation is used on the track to simulate the moving load of train. The results showed that modified analytical model gives the velocity response of 75 VdB at the maximum peak. Changes brought to the mass and spacing of the sleeper and to the thickness and the corresponding stiffness for the ballast does not result in significant vibration response. Limitations of two-degree analytical model is suspected to be the cause of this inactivity. But resonance vibration can be reduced with the aid of damping coefficient of rail pad. Statistical analysis methods t-test and ANOVA single factor test was used verify the values with 95% confidence.

On the Effect of External Bending Loads in Bolted Flange Joints

2007 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Yves Birembaut ◽  
Hubert Lejeune
Keyword(s):  
Analytical Model ◽  
Contact Stress ◽  
Analytical Approach ◽  
Bolted Joint ◽  
Acceptable Solution ◽  
Sealing Performance ◽  
Circumferential Distribution ◽  
Bending Loads ◽  
Minimum Stress ◽  
Bolted Flange

Most current flange design methods use an equivalent pressure to treat bolted flange connections subjected to external bending loads. This oversimplified approach together with the lack of a proper assessment of the actual affected tightness make these methods inadequate for modern flange design. The substitution of the external applied moment by an equivalent pressure is excessively conservative and not realistic since it assumes that the achieved tightness is that of a gasket unloaded entirely to a minimum stress whereas in reality only a small section of it is, the rest of it is actually at a much higher stress. The successfulness of a valid analytical approach in yielding to an acceptable solution resides in its ability to account for the circumferential distribution of the gasket contact stress and its effect on leakage. This paper presents an analytical model based on the flexibility of the flange to treat flanges subjected to bending loads such as those produced by external moments and misalignments and capable of integrating leakage around the gasket circumference. The bolted joint sealing performance in the presence of such loads is evaluated using the new PVRC gasket constants Gb, a and Gs obtained from ROTT tests. The analytical results including leakage predictions are validated by comparison to those obtained numerically by FEA and experimentally on different size flanges. The over-conservatism of the equivalent pressure is demonstrated.

scholarly journals Modeling of Laminar Flows in Rough-Wall Microchannels

2005 ◽  
Vol 128 (4) ◽  
pp. 734-741 ◽  
Author(s):  
R. Bavière ◽  
G. Gamrat ◽  
M. Favre-Marinet ◽  
S. Le Person
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Numerical Modeling ◽  
Pressure Drop ◽  
Analytical Model ◽  
Analytical Approach ◽  
Laminar Flows ◽  
Numerical Results ◽  
Rough Wall ◽  
Relative Roughness

Numerical modeling and analytical approach were used to compute laminar flows in rough-wall microchannels. Both models considered the same arrangements of rectangular prism rough elements in periodical arrays. The numerical results confirmed that the flow is independent of the Reynolds number in the range 1–200. The analytical model needs only one constant for most geometrical arrangements. It compares well with the numerical results. Moreover, both models are consistent with experimental data. They show that the rough elements drag is mainly responsible for the pressure drop across the channel in the upper part of the relative roughness range.

scholarly journals Allotypically related sequences in the Fd fragment of rabbit immunoglobulin heavy chains

1971 ◽  
Vol 124 (2) ◽  
pp. 301-318 ◽  
Author(s):  
L. E. Mole ◽  
S. A. Jackson ◽  
R. R. Porter ◽  
J. M. Wilkinson
Keyword(s):  
Heavy Chain ◽  
Immunoglobulin G ◽  
Sequence Variation ◽  
Variable Region ◽  
Related Sequence ◽  
Heavy Chains ◽  
Rabbit Immunoglobulin ◽  
Variable Section ◽  
Terminal Section ◽  
Constant Section

The sequence has been completed of the N-terminal 94 residues of the variable section of the Fd fragment of heavy chains from rabbit immunoglobulin G (IgG) of allotype As1. Most of the sequence of the same section from IgG of allotype Aa3 is also reported. These results, in conjunction with a substantial sequence of the variable region of allotype Aa2 reported elsewhere (Fleischman, 1971), show the presence of 16 positions (including six consecutive positions) in which the residue present correlates with the allotype. No allotype-related sequence variation has been found in the constant section of the Fd fragment. This evidence supports the view that two genes code for the heavy chain and it can be used as evidence in favour of somatic mutation as the origin of the variability in the sequence of the N-terminal section. The evolutionary origin of the ‘a’ locus allotypes of rabbit immunoglobulins remains obscure.

A Combined Analytical and Numerical Approach to Analyze Mud Motor Excited Vibrations in Drilling Systems

2015 ◽  
Author(s):  
Andreas Hohl ◽  
Carsten Hohl ◽  
Christian Herbig
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Field Measurements ◽  
Element Model ◽  
Numerical Approach ◽  
Analytical Models ◽  
Finite Element Models ◽  
Beam Model ◽  
Direct Influence ◽  
Practical Applications

Severe vibrations in drillstrings and bottomhole assemblies can be caused by cutting forces at the bit or mass imbalances in downhole tools. One of the largest imbalances is related to the working principle of the so-called mud motor, which is an assembly of a rotor that is maintained by the stator. One of the design-related problems is how to minimize vibrations excited by the mud motor. Simulation tools using specialized finite element methods (FEM) are established to model the mechanical behavior of the structure. Although finite element models are useful for estimating rotor dynamic behavior and dynamic stresses of entire drilling systems they do not give direct insight how parameters affect amplitudes and stresses. Analytical models show the direct influence of parameters and give qualitative solutions of design related decisions. However these models do not provide quantitative numbers for complicated geometries. An analytical beam model of the mud motor is derived to calculate the vibrational amplitudes and capture basic dynamic effects. The model shows the direct influence of parameters of the mud motor related to the geometry, material properties and fluid properties. The analytical model is compared to the corresponding finite element model. Vibrational amplitudes are discussed for different modes and parameter changes. Finite element models of the entire drilling system are used to verify the findings from the analytical model using practical applications. The results are compared to time domain and statistical data from laboratory and field measurements.

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