scholarly journals Exact Dynamic Characteristic Analysis of Steel-Concrete Composite Continuous Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qikai Sun ◽  
Nan Zhang ◽  
Guobing Yan ◽  
Xinqun Zhu ◽  
Xiao Liu ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Concrete Slab ◽  
Beam Theory ◽  
Interfacial Interaction ◽  
Span Length ◽  
Characteristic Analysis ◽  
Elastic Boundary ◽  
Continuous Beams ◽  
Direct Stiffness ◽  
Lumped Masses

The free vibration characteristics of steel-concrete composite continuous beams (SCCCBs) are analyzed based on the Euler–Bernoulli beam theory. A modified dynamic direct stiffness method has been developed, which can be used to analyze the SCCCBs with some lumped masses and elastic boundary conditions. The results obtained by the proposed method are exact due to the elimination of approximated displacement and force fields in derivation. The proposed method is verified by comparing its results with those obtained by ANSYS software and laboratory tests. Then, the influencing factors on the reduction of natural frequency are analyzed and discussed in detail using the proposed method. The results show that stronger interfacial interaction results in higher values of natural frequency as well as larger steel subbeam and thinner concrete slab. The smaller the natural frequency of the SCCCBs is, the more significant effect the interfacial interaction on the natural frequency is. The reduction of natural frequency is not affected by the different numbers of spans but the equal single-span length and various ratios of the side span to the main span but equal total length, but it is influenced by the extra single-span length and different ratios of the side span to the main span but equal main span length. And it is only affected by bending stiffness. Furthermore, the reasonable ratio of the side span to the main span is 0.9∼1.0.

Belt Vibration Consideration Moving Contact and Parametric Excitation

1992 ◽  
Author(s):  
M. G. Yue
Keyword(s):  
Natural Frequency ◽  
Dynamic Behavior ◽  
Parametric Excitation ◽  
Span Length ◽  
Automotive Applications ◽  
Moving Contact

Abstract The contacting point between belt and pulley is not fixed but moves along the pulley during vibration and that influences the free span length of the belt. The concept vibrating length is introduced and that will affect the dynamic behavior of the belt. Parametric excitation can occur through periodic variations in belt tension and speed arising from loading of the pulleys by belt-driven accessories and from engine in automotive applications. The most violent oscillations develop and resonance will occur when the frequency of excitation is close to twice or three times the natural frequency for varying tension and speed case, respectively.

Free vibration analysis and post-critical free vibrations of nanocomposite rotating beams reinforced with graphene platelet

2021 ◽  
pp. 107754632110511
Author(s):  
Arameh Eyvazian ◽  
Chunwei Zhang ◽  
Farayi Musharavati ◽  
Afrasyab Khan ◽  
Mohammad Alkhedher
Keyword(s):  
Natural Frequency ◽  
Thermal Environment ◽  
Rotational Velocity ◽  
Equations Of Motion ◽  
Free Vibration Analysis ◽  
Beam Theory ◽  
Weight Fraction ◽  
Free Vibrations ◽  
Graphene Platelet ◽  
The Impact

Treatment of the first natural frequency of a rotating nanocomposite beam reinforced with graphene platelet is discussed here. In regard of the Timoshenko beam theory hypothesis, the motion equations are acquired. The effective elasticity modulus of the rotating nanocomposite beam is specified resorting to the Halpin–Tsai micro mechanical model. The Ritz technique is utilized for the sake of discretization of the nonlinear equations of motion. The first natural frequency of the rotating nanocomposite beam prior to the buckling instability and the associated post-critical natural frequency is computed by means of a powerful iteration scheme in reliance on the Newton–Raphson method alongside the iteration strategy. The impact of adding the graphene platelet to a rotating isotropic beam in thermal ambient is discussed in detail. The impression of support conditions, and the weight fraction and the dispersion type of the graphene platelet on the acquired outcomes are studied. It is elucidated that when a beam has not undergone a temperature increment, by reinforcing the beam with graphene platelet, the natural frequency is enhanced. However, when the beam is in a thermal environment, at low-to-medium range of rotational velocity, adding the graphene platelet diminishes the first natural frequency of a rotating O-GPL nanocomposite beam. Depending on the temperature, the post-critical natural frequency of a rotating X-GPL nanocomposite beam may be enhanced or reduced by the growth of the graphene platelet weight fraction.

A new simplified method for anti-symmetric mode in-plane vibrations of frame structures with column cracks

2016 ◽  
Vol 24 (24) ◽  
pp. 5794-5810 ◽  
Author(s):  
Kemal Mazanoglu ◽  
Elif C Kandemir-Mazanoglu
Keyword(s):  
Beam Theory ◽  
Equivalent Model ◽  
Frame Structures ◽  
Symmetric Mode ◽  
Lumped Mass ◽  
Beam Elements ◽  
Local Flexibility ◽  
Mode Vibration ◽  
Frame Systems ◽  
Lumped Masses

This paper is on the natural frequency and mode shape computation of frame structures with column cracks. First, a model of intact frame structures is built to perform vibration analysis. Beam elements are considered as lumped masses and rotational springs at the storey levels of frames. Equivalent model of columns and lumped mass-stiffness effects of beams have been combined to carry out continuous solution for the anti-symmetric mode in-plane vibrations of frames. In addition, frame systems with multiple column cracks are analyzed in terms of anti-symmetric mode vibration characteristics. Cracks are considered as massless rotational springs in compliance with the local flexibility model. Compatibility and continuity conditions are satisfied at crack and storey locations of the equivalent column, modeled using the Euler–Bernoulli beam theory. The proposed method is tested for single-storey single- and multi-bay, H-type and double-storey single-bay frame systems with intact and cracked columns. Results are validated by those given in the current literature and/or obtained by the finite element analyses.

Natural Frequencies of Continuous Beams of Uniform Span Length

1950 ◽  
Vol 17 (4) ◽  
pp. 391-395
Author(s):  
R. S. Ayre ◽  
L. S. Jacobsen
Keyword(s):  
Natural Frequencies ◽  
Flexural Vibration ◽  
Span Length ◽  
Continuous Beams

Abstract A simple graphical network is used to determine the natural frequencies of flexural vibration of continuous beams having any number of spans of uniform length. The network is based upon a relatively few calculated values.

Axial Load on the Submarine Pipeline Suspended Law of Vortex Induced Vibration

2011 ◽  
Vol 94-96 ◽  
pp. 1511-1514
Author(s):  
Yi Fei Yan
Keyword(s):  
Natural Frequency ◽  
Axial Force ◽  
Scientific Basis ◽  
Oil Field ◽  
Span Length ◽  
Submarine Pipeline ◽  
Vortex Induced Vibration ◽  
Vibration Effect ◽  
Pipeline Vibration ◽  
The Impact

The study is about submarine pipeline. Considering the impact of different axial force, The reduced velocity is introduced as the pipeline vibration effect of vortex trail releasing. The vibration parameters of the span pipeline are analyzed and vibration control formula is built. The natural span length of the submarine pipeline is calculated according to the DNV-OS-F101 rule. The natural frequency of the span pipeline and the allowable span length are solved. The case study of submarine pipeline in Chengdao oil field is made and the variation law of natural frequency of span pipeline is got. The stream reduced velocity decreases as the axial force increase. The theory analysis of the vortex induced vibration can provide the scientific basis for the safety design of offshore submarine pipeline.

Vibration Characteristic Analysis of V-Shaped Electrothermal Microactuator

2012 ◽  
Vol 503 ◽  
pp. 118-121
Author(s):  
Zhen Lu Wang ◽  
Xue Jin Shen ◽  
Ling Zhou ◽  
Xiao Yang Chen
Keyword(s):  
Theoretical Calculation ◽  
Natural Frequency ◽  
Mechanical Model ◽  
Natural Frequencies ◽  
Maximum Error ◽  
Vibration Characteristic ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
The Finite Element Analysis

This paper is focused on the finite element analysis (FEA) and theoretical calculation of vibration characterization of V-shaped electrothermal microactuator. A vibration mechanical model about V-shaped electrothermal microactuator is presented. By having a comparison between FEA and theoretical calculation about natural frequencies of V-shaped electrothermal microactuator, the maximum error is within 0.19 %. This paper also analyzes the influences of microactuator geometric parameters on natural frequency. The length and thickness have larger effect on the natural frequency of the actuator, while the angle and width have less effect on the natural frequency.

Nonlinear Vibration of Nanobeam With Quadratic Rational Bezier Arc Curvature

2014 ◽  
Author(s):  
Hassan Askari ◽  
Zia Saadatnia ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Nonlinear Vibration ◽  
Natural Frequency ◽  
Governing Equation ◽  
Oscillation Amplitude ◽  
Beam Theory ◽  
Nonlinear Ordinary Differential Equation ◽  
Pasternak Foundation ◽  
Bernoulli Beam ◽  
Linear Frequency ◽  
Euler Bernoulli Beam

Nonlinear vibration of nanobeam with the quadratic rational Bezier arc curvature is investigated. The governing equation of motion of the nanobeam based on the Euler-Bernoulli beam theory is developed. Accordingly, the non-uniform rational B-spline (NURBS) is implemented in order to write the implicit form of the governing equation of the structure. The simply-supported boundary conditions are assumed and the Galerkin procedure is utilized to find the nonlinear ordinary differential equation of the system. The nonlinear natural frequency of the system is found and the effects of different parameters, namely, the waviness amplitude, oscillation amplitude, aspect ratio, curvature shape and the Pasternak foundation coefficient are fully investigated. The hardening and softening responses of the natural frequency of structure are detected for variations of the shape and amplitude of the curvature waviness. It is revealed that the ratio of nonlinear to linear frequency increases with an increase in the oscillation amplitudes. It is found that by increasing the Pasternak foundation coefficient, the ratio of nonlinear to linear frequency decreases.

Pipeline Free Spans: Influence of Internal Pressure

2010 ◽  
Author(s):  
Olav Fyrileiv ◽  
Olav Aamlid ◽  
Erik Andreassen
Keyword(s):  
Internal Pressure ◽  
Natural Frequency ◽  
Structural Integrity ◽  
High Pressures ◽  
Fluid Temperature ◽  
Span Length ◽  
Operational Parameters ◽  
Deep Waters ◽  
Induced Flow ◽  
Wave Induced

The trend the last decades has been to develop the offshore fields by use of Subsea templates and flowline tie-backs rather than traditional platforms and topside processing. The exploitation of new offshore fields has moved towards deep waters, rougher seabed and reservoirs with high temperatures and high pressures. As flowlines are not necessarily trenched and buried, an uneven seabed may cause significant free spans. Then, if the current and wave induced flow velocities are sufficient, the free spans may be exposed to cyclic loading and associated fatigue failure. One of the governing parameters to ensure the structural integrity of free spans is the natural frequency of the span. As such it is in many cases of vital importance to estimate a realistic value of this frequency. The natural frequency is mainly determined by the bending stiffness and the span length but also operational parameters like the internal pressure and the fluid temperature. Recently some papers have been published that claim to prove that the effect of the internal pressure is the opposite of what has been the understanding in the industry and given by various codes. This paper tries to give an overview of the effect of the internal pressure and hopefully clarify what is believed to be misinterpretations of some experimental data.

Member Initial Curvature Effects on the Elastic Slider-Crank Mechanism Response

1982 ◽  
Vol 104 (1) ◽  
pp. 159-167 ◽  
Author(s):  
M. Badlani ◽  
A. Midha
Keyword(s):  
Steady State ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Connecting Rod ◽  
Initial Curvature ◽  
Curvature Effects ◽  
Transient Solutions ◽  
Crank Mechanism

Parametric vibration of initially curved columns loaded by axial-periodic loads has received considerable attention, concluding that regions of instability exist and that excitation frequencies less than the natural frequency of the principal resonance may occur. Recent publications have cautioned against the use of curved members in machines designed for precise operation, suggesting a detrimental coupling of the longitudinal and transverse deformations. In this work, the dynamic behavior of a slider-crank mechanism with an initially curved connecting rod is investigated. Governing equations of motion are developed using the Euler-Bernoulli beam theory. Both steady-state and transient solutions are determined, and compared with those obtained for the mechanism possessing a geometrically perfect (straight) connecting rod. A very small initial curvature is shown to cause a significantly greater steady-state response. The magnification in its transient response is shown to be even greater than that due to a straight connecting rod. Additionally, an excitation frequency less than the natural frequency is also shown to occur.

Sign in / Sign up

Export Citation Format

Share Document