Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5

moving load Related Abstracts

5 Design and Manufacture of Non-Contact Moving Load for Experimental Analysis of Beams

Authors: Hamidreza Rostami, Mona Zandbaf, Firooz Bakhtiari-Nejad, Meysam Mirzaee

Abstract:

Dynamic tests are an important step of the design of engineering structures, because the accuracy of predictions of theoretical–numerical procedures can be assessed. In experimental test of moving loads that is one of the major research topics, the load is modeled as a simple moving mass or a small vehicle. This paper deals with the applicability of Non-Contact Moving Load (NML) for vibration analysis. For this purpose, an experimental set-up is designed to generate the different types of NML including constant and harmonic. The proposed method relies on pressurized air which is useful, especially when dealing with fragile or sensitive structures. To demonstrate the performance of this system, the set-up is employed for a modal analysis of a beam and detecting crack of the beam. The obtained results indicate that the experimental set-up for NML can be an attractive alternative to the moving load problems.

Keywords: Materials Engineering, Experimental Analysis, moving load, non-contact excitation

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4 Dynamic Analysis of Functionally Graded Nano Composite Pipe with PZT Layers Subjected to Moving Load

Authors: Morteza Raminnia

Abstract:

In this study, dynamic analysis of functionally graded nano-composite pipe reinforced by single-walled carbon nano-tubes (SWCNTs) with simply supported boundary condition subjected to moving mechanical loads is investigated. The material properties of functionally graded carbon nano tube-reinforced composites (FG-CNTRCs) are assumed to be graded in the thickness direction and are estimated through a micro-mechanical model. In this paper polymeric matrix considered as isotropic material and for the CNTRC, uniform distribution (UD) and three types of FG distribution patterns of SWCNT reinforcements are considered. The system equation of motion is derived by using Hamilton's principle under the assumptions of first order shear deformation theory (FSDT).The thin piezoelectric layers embedded on inner and outer surfaces of FG-CNTRC layer are acted as distributed sensor and actuator to control dynamic characteristics of the FG-CNTRC laminated pipe. The modal analysis technique and Newmark's integration method are used to calculate the displacement and dynamic stress of the pipe subjected to moving loads. The effects of various material distribution and velocity of moving loads on dynamic behavior of the pipe is presented. This present approach is validated by comparing the numerical results with the published numerical results in literature. The results show that the above-mentioned effects play very important role on dynamic behavior of the pipe .This present work shows that some meaningful results that which are interest to scientific and engineering community in the field of FGM nano-structures.

Keywords: Active Control, moving load, nano-composite, functionally garded material, PZT layers

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3 Numerical Simulation of a Three-Dimensional Framework under the Action of Two-Dimensional Moving Loads

Authors: Jia-Jang Wu

Abstract:

The objective of this research is to develop a general technique so that one may predict the dynamic behaviour of a three-dimensional scale crane model subjected to time-dependent moving point forces by means of conventional finite element computer packages. To this end, the whole scale crane model is divided into two parts: the stationary framework and the moving substructure. In such a case, the dynamic responses of a scale crane model can be predicted from the forced vibration responses of the stationary framework due to actions of the four time-dependent moving point forces induced by the moving substructure. Since the magnitudes and positions of the moving point forces are dependent on the relative positions between the trolley, moving substructure and the stationary framework, it can be found from the numerical results that the time histories for the moving speeds of the moving substructure and the trolley are the key factors affecting the dynamic responses of the scale crane model.

Keywords: moving load, dynamic responses, moving substructure, forced vibration responses

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2 Dynamic Analysis of a Moderately Thick Plate on Pasternak Type Foundation under Impact and Moving Loads

Authors: Neslihan Genckal, Reha Gursoy, Vedat Z. Dogan

Abstract:

In this study, dynamic responses of composite plates on elastic foundations subjected to impact and moving loads are investigated. The first order shear deformation (FSDT) theory is used for moderately thick plates. Pasternak-type (two-parameter) elastic foundation is assumed. Elastic foundation effects are integrated into the governing equations. It is assumed that plate is first hit by a mass as an impact type loading then the mass continues to move on the composite plate as a distributed moving loading, which resembles the aircraft landing on airport pavements. Impact and moving loadings are modeled by a mass-spring-damper system with a wheel. The wheel is assumed to be continuously in contact with the plate after impact. The governing partial differential equations of motion for displacements are converted into the ordinary differential equations in the time domain by using Galerkin’s method. Then, these sets of equations are solved by using the Runge-Kutta method. Several parameters such as vertical and horizontal velocities of the aircraft, volume fractions of the steel rebar in the reinforced concrete layer, and the different touchdown locations of the aircraft tire on the runway are considered in the numerical simulation. The results are compared with those of the ABAQUS, which is a commercial finite element code.

Keywords: Impact, moving load, elastic foundation, thick plate

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1 Mathematical Analysis of Simple Supported Euler-Bernoulli Beam on a Variable Elastic Foundation under a Partially Distributed Moving Load

Authors: I. A. Idowu, A. A. Owolabi, S. O. Sogunro, F. O. Akinpelu

Abstract:

The dynamic responses of an elastically supported Euler- Bernoulli beam on variable elastic foundation under partially distributed moving loads were investigated. The governing equation is fourth order partial differential equation, which was reduced to second order ordinary differential equation by using the analytical method in terms of series solution and solved by a numerical method using mathematical software (Maple). The numerical analysis shows that the response amplitude of the moving mass and moving force for variable pre-stressed increase as mass of the load M increases. It was found that the response displacement of the beam decreases as the value of the elastic foundation K increases. Also, the response displacement of the beam decreases as the value of the pre-stressed N increase. Comparison of moving mass and moving force shown that moving mass is greater than that of moving force.

Keywords: moving load, elastic foundation, Euler-Bernoulli beam, Variable pre-stressed, partially distributed, moving force

Procedia PDF Downloads 106