INFORMATIVO ABCM Nº 050/07 – Uncertainties in Nonlinear Structural Dynamics

Uncertainties in Nonlinear Structural Dynamics

Call for Papers

Nonlinear dynamical systems usually display high complexity. The last decades hasseen a remarkable and fruitful development of nonlinear dynamics and a large number of papers have been published in all branches of science.

In modeling natural and man-made systems, it is assumed in general that the systems perfect and that all parameters of the system are known. However, real systemsare usually imperfect and uncertainties are present both in system parameters and inthe modeling stage. This is associated with the lack of precise knowledge of thesystem parameters, random or noisy external loading, operating conditions andvariability in manufacturing processes, among other things. In many situations, theseuncertainties are not important and may be overlooked in the mathematical modelingof the problem. However, in several situations, the uncertainties can have significantinfluence on the dynamic response and the stability of the system.

Uncertainties may also be found in system response, even in cases where allparameters are well established, such systems exhibiting high sensitivity to initialconditions.

This is particularly important in strongly nonlinear chaotic systems and those withfractal-basin boundaries.

Also, in many systems, unexpected interactions between different parts of thesystems such as in nonideal problems may lead to complex responses.

However, the influence of uncertainties on local and global bifurcations and basins ofattractions and on important engineering concepts such as reliability, safety, androbustness is not well studied in literature.

Even the definition of a random bifurcation is still an open problem in nonlineardynamics.

This is a rather broad topic in nonlinear dynamics. So, the present special issue willbe dedicated to the influence of uncertainties on structural dynamics (beams, plates,shells, frames, etc.). In these structures, the main sources of uncertainties are:

• Imperfections.
• Uncertainties in system parameters (mass, damping, and stiffness).
• Uncertainties in the external load, such as random loads (wind, earthquake,etc.)
• Sensitivity to initial conditions.
• Interaction between load and structure.
• These types of uncertainties coupled to system nonlinearities may have a markedinfluence on the structure’s response, particularly in a dynamic environment.

So it is useful to study their influence on bifurcations, stability boundaries, and basinsof attraction.

It is also interesting to discuss their influence on safety factors, integrity measures,and confiability.

These topics are essential for a safe design of structures and the development ofmathematically based safe (but not too conservative) design codes andmethodologies. Since structural systems may be studied using both continuous anddiscretized models, problems involving PDEs and ODEs should be considered.There is a large scientific community working on nonlinear dynamics of structuresthat may contribute to this special issue.

Authors should follow the Mathematical Problems in Engineering manuscript format described at the journal site http://www.hindawi.com/journals/mpe/. Prospective authors should submit an electronic copy of their complete manuscript through the journal’s Manuscript Tracking System at http://www.hindawi.com/mts/, according to the following timetable.

Manuscript Due		October 1, 2007
First Round of Reviews		January 1, 2008
Publication Date		April 1, 2008

Guest Editors:

José Manoel Balthazar, Department of Statistics, Applied Mathematics andComputation, State University of Sao Paulo at Rio Claro(UNESP), 13500-230 Rio Claro, SP, Brazil

Paulo Batista Gonçalves, Civil Engineering Department, Catholic University (PUC-Rio), 22453-900 Rio de Janeiro, RJ, Brazil

Reyolando M. R. L. F. Brasil, Department of Structural and Geotechnical Engineering, Polytechnic School, The University of Säo Paulo (PEF/EPUSP/USP) 05508-900 Säo Paulo, SP,Brazil