ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
- A.S. Foryś, A. Foryś:
Three-parameter optimization of an axially loaded beam on a foundation
- A. Ambroziak:
Modelling of continuum damage for application in elasto-viscoplastic bodner-partom constitutive equations
- A. Maciąg:
Wave polynomials in elasticity problems
- T.R. Ori, M.N. Ichchou, P. Gbaha, L. Jezequel:
Improvement of handling by means of active suspension control
- W. Szczepiński:
A comparative analysis of theoretical models of gravity movements of cohesionless granular media
- A.S. Foryś, A. Foryś:
Three-parameter optimization of an axially loaded beam on a foundation
- A beam of circular cross-section, made of viscoelastic material of Kelvin-Voigt type, is considered. The beam is symmetric with respect to its center,
the length and volume of the beam are fixed and its ends are simply sup-
ported. The radius of the cross-section is a cubic function of co-ordinate.
The beam interacts with a foundation of Winkler, Pasternak or Hetenyi type
and is axially loaded by a non-conservative force P(t) = P0 + P1 cos ϑ t.
Only the first instability region is taken into account. The shape of the beam
is optimal if the critical value of P1 is maximal. A few numerical examples
are presented on graphs.
Contents
- A. Ambroziak:
Modelling of continuum damage for application in elasto-viscoplastic bodner-partom constitutive equations
- The aim of the paper is to propose an application of the continuum
damage model proposed by Lemaitre to the elasto-viscoplastic constitutive
equations of the Bodner-Partom model. The proposed approach has been
implemented into subroutines of the FE code MSC.Marc as the user's viscoplastic subroutine UVSCPL and has been used to perform the FE numerical simulations. Comparison is given of the following two variants: 1) uniaxial creep test results for a nickel-based B1900+Hf superalloy at high temperatures and 2) calculation based on the constitutive equations with
the inclusion of isotropic damage models.
Contents
- A. Maciąg:
Wave polynomials in elasticity problems
- The paper demonstrates a new technique of obtaining the approximate solution of the two- and three-dimensional elasticity problems. The system of equations of elasticity can be converted to the system of wave equation.
In this case, as solving functions (Trefftz functions), the so-called wave polynomials can be used. The presented method is useful for a finite body of a certain shape. Then the obtained solutions are coupled through initial and
boundary conditions. Recurrent formulas for the two- and three-dimensional wave polynomials and their derivatives are obtained. The methodology for solution of systems of partial differential equations with common initial and
boundary conditions by means of solving functions is presented. The advantage of using the method of solving functions is that the solution exactly satisfies the given equation (or system of equations). Some examples are included.
Contents
- T.R. Ori, M.N. Ichchou, P. Gbaha, L. Jezequel:
Improvement of handling by means of active suspension control
- Brake systems have become increasingly complex. They must not only
slow down or stop a vehicle under extreme conditions within short distances,
but also reduce the effort exerted by the driver. This phenomenon is difficult
to approach because it depends on the vehicle's architecture. This is why,
in this paper, the first part will give the basis for modelling of the complete
vehicle including the frame and the tires, in a 3D format. A 2D control
law model will be synthesized to obtain the best performances for road
behaviour. This control law is based on the theory of Linear Quadratic
control (LQ). It is also extended to cover the 3D vehicle model. The last part
gives the numerical simulation results which demonstrate the effectiveness
of this law for vehicle performances.
Contents
- W. Szczepiński:
A comparative analysis of theoretical models of gravity movements of cohesionless granular media
- Three different theoretical models for the analysis of movements of granular media caused by the gravity forces only are critically discused. In each of them the motion is treated as a purely kinematical problem. It has been
shown that in application to varoius practical problems, they lead to different displacements patterns (e.g. funnel or mass flow, formation of shear bands or a flow without such bands). Examples of application illustrate the discussion.
Contents
Reprints of the full papers may be obtained from their authors.
Contact Editorial Office in case you need
the address of the respective author.
Previous issue
