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1

Vibrations of an orthotropic plate with point supports subjected to a moving force

Zakęś Filip

Engineering Transactions

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2023

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Vol. 71, iss. 3

307--328

EN

We investigate the dynamic behavior of a rectangular orthotropic plate loaded with the concentrated force moving with constant speed along the structure. In this work, we consider two types of plates in terms of boundary conditions. In the first case, we assume that the plate is simply supported on all of its edges with a number of point supports arbitrarily located in its area, and in the second one, we look at a two-span bridge plate with arbitrarily oriented intermediate linear support. Solutions for both cases are obtained by replacing the original structure with a single-span plate subjected to a given moving load and redundant forces situated in positions of removed intermediate supports. Redundant forces are obtained by the application of Volterra integral equations for the simply supported plate, and finite difference discretization and the Newmark method for the bridge plate. Two numerical examples are given to prove the effectiveness of the presented approach.

2

Vibrations of a double-beam system with intermediate elastic restraints due to a moving force

Zakęś Filip, Śniady Paweł

Engineering Transactions

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2019

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Vol. 67, iss. 2

243--252

EN

In this paper, we investigate the problem of the dynamic behaviour of a double-beam system with intermediate elastic restraints subjected to a moving point force. Problem is solved by replacing this type of structure with two single-span beams loaded with a given moving force and redundant forces representing reactions in the intermediate restraints. Redundant forces are obtained by solving Volterra integral equations of the second order which are compatibility equations corresponding to each redundant. Solutions for the arbitrarily supported singlespan beam loaded with a moving point force and concentrated time-varying force are given. Difficulties in analytically solving Volterra integral equations are bypassed by applying a simple numerical procedure. Finally, a numerical example of a double-beam system with two elastic restraints is presented in order to show the effectiveness of the presented method.

3

A nonstandard Volterra integral equation on time scales

Reinfelds Andrejs, Christian Shraddha

Demonstratio Mathematica

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2019

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Vol. 52, nr 1

503--510

EN

This paper introduces the more general result on existence, uniqueness and boundedness for solutions of nonstandard Volterra type integral equation on an arbitrary time scales. We use Lipschitz type function and the Banach’s fixed point theorem at functional space endowed with a suitable Bielecki type norm. Furthermore, it allows to get new sufficient conditions for boundedness and continuous dependence of solutions.

4

Vibrations of point-supported rectangular thin plate subjected to a moving force

Zakęś F.

Engineering Transactions

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2016

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Vol. 64, iss. 4

409--415

EN

In this paper, the dynamic behaviour of a rectangular thin plate simply supported on all edges and point supported within its region is investigated. The problem is solved by replacing this type of structure with a simply supported plate subjected to a given moving load and redundant forces situated in positions of intermediate point supports. Redundant forces are obtained by solving Volterra integral equations of the first order, which are compatibility equations corresponding to each redundant. Solutions for a simply supported plate loaded with a moving point force and concentrated time-varying force are given. Difficulties of solving Volterra integral equations analytically are bypassed by applying a simple numerical procedure. Finally, a numerical example of a plate with two point supports is presented in order to show the effectiveness of the presented method.

5

Bounded, asymptotically stable, and L1 solutions of caputo fractional differential equations

Islam M.N.

Opuscula Mathematica

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2015

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Vol. 35, no. 2

181--190

EN

The existence of bounded solutions, asymptotically stable solutions, and L1 solutions of a Caputo fractional differential equation has been studied in this paper. The results are obtained from an equivalent Volterra integral equation which is derived by inverting the fractional differential equation. The kernel function of this integral equation is weakly singular and hence the standard techniques that are normally applied on Volterra integral equations do not apply here. This hurdle is overcomed using a resolvent equation and then applying some known properties of the resolvent. In the analysis Schauder's fixed point theorem and Liapunov's method have been employed. The existence of bounded solutions are obtained employing Schauder's theorem, and then it is shown that these solutions are asymptotically stable by a definition found in [C. Avramescu, C. Vladimirescu, On the existence of asymptotically stable solution of certain integral equations, Nonlinear Anal. 66 (2007), 472-483]. Finally, the L1 properties of solutions are obtained using Liapunov's method

6

Convergence analysis of piecewise continuous collocation methods for higher index integral algebraic equations of the Hessenberg type

Shiri B., Shahmorad S., Hojjati G.

International Journal of Applied Mathematics and Computer Science

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2013

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Vol. 23, no. 2

341--355

EN

In this paper, we deal with a system of integral algebraic equations of the Hessenberg type. Using a new index definition, the existence and uniqueness of a solution to this system are studied. The well-known piecewise continuous collocation methods are used to solve this system numerically, and the convergence properties of the perturbed piecewise continuous collocation methods are investigated to obtain the order of convergence for the given numerical methods. Finally, some numerical experiments are provided to support the theoretical results.