A new finite element for transverse vibration of rectangular thin plates under a moving mass

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A combined plate element is presented for the analysis of transverse and longitudinal vibrations of a thin plate which carries a load moving along an arbitrary trajectory with variable velocity. Depending on the acceleration of the point load on its trajectory on the plate surface, the combined element, which is a combination of the 24 DOF plate element and an equivalent mass element, represents transverse (z) inertia, Coriolis and centripetal and longitudinal (x, y) inertia effects of the moving load. In order to obtain the combined element, mass, damping and stiffness matrices of the equivalent mass element representing the mass are first derived by using the relations between nodal forces, nodal deflections and deflection-shape functions of the plate element and the inertia and other forces of the moving mass according to the global coordinates on the plate and local coordinates on the plate element. Then, the obtained property matrices of the equivalent mass element and property matrices of the plate element were added together in order to obtain the combined plate element. For verification, the suggested technique was applied on a simply supported beam-plate under a moving load, and agreements were obtained with existing literature. In addition, intensive analysis and simulations were conducted at different dimensionless mass rates (mass of the load/mass of the plate) and angular velocities for a circular motion on a CCCC plate, and the results are provided. Furthermore, analysis results are provided for moving force condition which neglects the inertia, Coriolis and centripetal effects of the load, and it was shown that the moving mass assumption generated very different results with moving load assumption especially at high mass ratio and velocity values. Analysis results made it clear that the dynamic behaviour of the plate was differently affected by an orbiting mass depending on its mass ratio, orbiting radius and angular velocity

Section: Case Study: Orbiting Masssupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

A new FEM procedure for transverse and longitudinal vibration analysis of thin rectangular plates subjected to a variable velocity moving load along an arbitrary trajectory

Esen

2015

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“…In the case of moving load, there are two models frequently used in the literature (Wu et al, 2000;Esen, 2013): the moving force model and the moving mass model. In the former model, the force is assumed to be constant and equal to the weight of the moving body,…”

Section: Fe Model For Structurementioning

confidence: 99%

Time-Domain Three Dimensional BE-FE Method for Transient Response of Floating Structures Under Unsteady Loads

Ismail

2016

This paper presents a direct time-domain three dimensional (3D) numerical procedure to simulate the transient response of very large floating structures (VLFS) subjected to unsteady external loads as well as moving mass. The proposed procedure employs the Boundary Element and Finite Element methods (FEM-BEM).The floating structure and the surrounding fluid are discretized by 4-node isoparametric finite elements (FE) and by 4-node constant boundary elements (BE), respectively. Structural analysis is based on Mindlin's plate theory. The equation of motion is constructed taking into account the effect of inertia loading due to the moving mass. In order to obtain the hydrodynamic forces (added mass and radiation damping), the coupled natural frequencies are first obtained by an iterative method, since hydrodynamic forces become frequency-dependent. Then the Newark integration method is employed to solve the equation of motion for structural system. In order to prove the validity of the present method, a FORTRAN program is developed and numerical examples are carried out to compare its results with those of published experimental results of a scale model of VLFS under a weight drop and airplane landing and takeoff in still water condition. The comparisons show very good agreement.

“…For the application to the bridge engineering (Michaltsos et al, 1996) have studied the effect of accelerating vehicles on the bridge beams, considering highway bridges and high speed rail road construction. Some more accurate tools of engineering calculations of the dynamic interaction using FEM have been proposed by (Esen, 2011(Esen, , 2015(Esen, , 2013Kahya, 2012) . Using analytical methods for simple cases neglecting damping effects and assuming uniform beam cross sections (Esmailzadeh and Jalili, 2003;Liu et al, 2015;Wyss et al, 2011) have studied the subject in terms of vehicle structure interaction problems.…”

Section: Introductionmentioning

confidence: 99%

Tip Deflection Determination of a Barrel for the Effect of an Accelerating Projectile Before Firing Using Finite Element and Artificial Neural Network Combined Algorithm

Koç

Esen

Çay

2016

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For realistic applications, design and control engineers have limited modelling options in dealing with some vibration problems that hold many nonlinearity such as non-uniform geometry, variable velocity loadings, indefinite damping cases, etc. For these reasons numerous time consuming experimental studies at high costs must be done for determining the actual behaviour such nonlinear systems. However, using advantages of multiple computational methods like Finite Element Method (FEM) together with an Artificial Intelligence (ANN), many complicated engineering problems can be handled and solved to some extent. This study, proposes a new collective method to deal with the nonlinear vibrations of the barrels in order to fulfil accurate shooting expectancy. Using known analytical methods, in practical, to determine dynamic behaviour of the barrel beam is not possible for all conditions of firing that include numerous varieties of ammunition for different purposes, and each projectile of different ammunition has different mass and exit velocity. In order to cover all cases this study proposes a new method that combines a precise FEM with ANN, and can be used for determining the exact dynamic behaviour of a barrel for some cases and then for precisely predicting the behaviour for all other possible cases of firing. In this study, the whole nonlinear behaviour of an antiaircraft barrel were obtained with 3.5% accuracy errors by ANN trained by FEM using calculated analysis results of ammunitions for a particular range. The proposed FEM-ANN combined method can be very useful for design and control engineers in design and control of barrels in order to compensate the effect of nonlinear vibrations of a barrel for achieving a higher shooting accuracy; and can reduce high-cost experimental works.