Search results for "Principle"

A note on the closed graph theorem

1977

A regular variational boundary model for free vibrations of magneto-electro-elastic structures

2011

In this paper a regular variational boundary element formulation for dynamic analysis of two-dimensional magneto-electro-elastic domains is presented. The method is based on a hybrid variational principle expressed in terms of generalized magneto-electro-elastic variables. The domain variables are approximated by using a superposition of weighted regular fundamental solutions of the static magneto-electro-elastic problem, whereas the boundary variables are expressed in terms of nodal values. The variational principle coupled with the proposed discretization scheme leads to the calculation of frequency-independent and symmetric generalized stiffness and mass matrices. The generalized stiffne…

A meshfree method for transverse vibrations of anisotropic plates

2003

A meshfree approach, called displacement boundary method, for anisotropic Kirchhoff plate dynamic analysis is presented. This method is deduced from a variational principle, which uses a modified hybrid functional involving the generalized displacements and generalized tractions on the boundary and the lateral deflection in the domain as independent variables. The discretization process is based on the employment of the fundamental solutions of the static problem operator for the expression of the variables involved in the functional. The stiffness and mass matrices obtained for the dynamic model are frequency-independent, symmetric and positive definite and their computation involves bound…

BIEM-based variational principles for elastoplasticity with unilateral contact boundary conditions

1998

The structural step problem for elastic-plastic internal-variable materials is addressed in the presence of frictionless unilateral contact conditions. Basing on the BIEM (boundary integral equation method) and making use of deformation-theory plasticity (through the backward-difference method of computational plasticity), two variational principles are shown to characterize the solution to the step problem: one is a stationarity principle having as unknowns all the problem variables, the other is a saddle-point principle having as unknowns the increments of the boundary tractions and displacements, along with the plastic strain increments in the domain. The discretization by boundary and i…

Robust stabilisation of 2D state-delayed stochastic systems with randomly occurring uncertainties and nonlinearities

2013

This paper is concerned with the state feedback control problem for a class of two-dimensional (2D) discrete-time stochastic systems with time-delays, randomly occurring uncertainties and nonlinearities. Both the sector-like nonlinearities and the norm-bounded uncertainties enter into the system in random ways, and such randomly occurring uncertainties and nonlinearities obey certain mutually uncorrelated Bernoulli random binary distribution laws. Sufficient computationally tractable linear matrix inequality–based conditions are established for the 2D nonlinear stochastic time-delay systems to be asymptotically stable in the mean-square sense, and then the explicit expression of the desired…

Determination of Pareto frontier in multi-objective maintenance optimization

2011

Abstract The objective of a maintenance policy generally is the global maintenance cost minimization that involves not only the direct costs for both the maintenance actions and the spare parts, but also those ones due to the system stop for preventive maintenance and the downtime for failure. For some operating systems, the failure event can be dangerous so that they are asked to operate assuring a very high reliability level between two consecutive fixed stops. The present paper attempts to individuate the set of elements on which performing maintenance actions so that the system can assure the required reliability level until the next fixed stop for maintenance, minimizing both the globa…

Mode-superposition correction method for deterministic and stochastic analysis of structural systems

2001

The role played by the modal analysis in the framework of structural dynamics is fundamental from both deterministic and stochastic point of view. However the accuracy obtained by means of the classical modal analysis is not always satisfactory. Therefore it is clear the importance of methods able to correct the modal response in such a way to obtain the required accuracy. Many methods have been proposed in the last years but they are meaningful only when the forcing function is expressed by an analytical function. Moreover in stochastic analysis they fail for white noise excitation. In the paper a method able to give a very accurate response for both deterministic and stochastic input is p…

"Table 1" of "First measurement of f2-prime (1525) production in Z0 hadronic decays"

1996

SIG in (1/SIG) is the total hadronic cross section.

The fundamental Human Rights as European Law Principles: their development through the ECHR principles and the Constitutional traditions conmmon to t…

2011

The need to reinforce the fundamental human rights of EU citizens and of people living in the European Union became a key goal linked to the need to create a European area of freedom, security and justice, one European Union's internal borders were gradually abolished. Respecting fundamental rights while ensuring security and justice in the European Union became two intrinsically linked tasks of European integration in the years to come. Actually two sides of the same coin. Look, for example, the immigration policy. The latest developments have even led to the creation of a Fundamental Rights Agency.

Premessa

2021

It explains the evolution of the ne bis in idem principle at national as well as at supranational level