ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
- Sz. Imiełowski, R. Bogacz:
Stability constraints in optimization of cracked columns subjected to compressive follower load
- P. Koutmos, G. Giannakis, P. Marazioti:
A global oxidation scheme for propane-air combustion suitable for use into complex reacting flow computations
- K. Cabańska-Płaczkiewicz:
Dynamics of the complex system with elastic and visco-elastic inertial interlayers
- E. Włodarczyk:
Normal penetration of the rigid penetrator into elastic-plastic half-space with viscosity
- Sz. Imiełowski, R. Bogacz:
Stability constraints in optimization of cracked columns subjected to compressive follower load
- Maximization of the critical force of cracked columns, subjected to generalized follower
force is discussed in the paper. The crack is assumed to be formed according to the opening
and sliding modes and is modeled by a localized loss of stiffness. Influence of the crack stiffness
and its localization on the value of the critical force is analyzed. The optimization process
is based on the multimodal approach. The localization of crack with the critical force of the
system equal to 137.17 EJ/L2 is found.
Contents
- P. Koutmos, G. Giannakis, P. Marazioti:
A global oxidation scheme for propane-air combustion suitable for use into complex reacting flow computations
- In Direct or Semi-Direct Numerical Simulations of turbulent reacting flows the exploitation
of complex, realistic and detailed chemistry and transport models often results in prohibitive
memory and CPU requirements when flows of practical relevance are treated.
- The integrated Combustion Chemistry approach has recently been put forward as a
methodology suitable for the integration of complex chemical kinetic and chemistry effects
into large scale computational procedures for the calculation of complex and practical reacting
flow configurations. Through this procedure, a reduced chemical kinetic scheme involving only
a limited number of species and reactions is derived from a detailed chemical mechanism, so as
to include major species and pollutants of interest in the main flow calculation. The chemical
parameters employed in this integrated scheme i.e. rates, constants, exponents are then calibrated
on the basis of a number of constraints and by comparing computations over a range
of carefully selected laminar flames so as to match a number of prespecified flame properties
such as adiabatic temperatures, selected target species profiles, flame speeds, extinction characteristics.
The present work describes such an effort for a commonly used fuel of both the
fundamental and practical importance that often is used to simulate the performance of higher
hydrocarbons in practical engine simulations, i.e. propane. The proposed nine-step scheme involves
nine major stable species and in addition to the basic propane oxidation model also
includes NOX production and soot formation submodels.
Contents
- K. Cabańska-Płaczkiewicz:
Dynamics of the complex system with elastic and visco-elastic inertial interlayers
- In this paper is given the dynamic analysis of the free and forced vibration problems of
a complex system with elastic and visco-elastic inertial interlayers. The analytical method of
solving the free and forced vibrations problem of the system is presented in the paper [2].
The external layer of the complex system is treated as the plate made from elastic materials,
coupled by visco-elastic inertial interlayers. The plate is described by the Kirchhoff-Love
model. The visco-elastic, inertial interlayer possesses the characteristics of a continuous inertial
Winkler foundation and has been described by the Voigt-Kelvin model. Small transverse
displacements of the complex system are excited by the stationary and non-stationary dynamical
loadings. The phenomenon of free and forced vibrations problems has been described
using a non-homogeneous system of conjugate, partial differential equations. After separation
of variables in the homogeneous system, the boundary value problem has been solved and two
sequences have been obtained: the sequences of frequencies and the sequences of free vibrations
modes. Then, the property of orthogonality of complex free vibrations has been presented.
The free vibrations problem has been solved for some arbitrarily assumed initial conditions.
The forced vibrations problem has been considered for different modes of dynamical loading [3].
- The solution of the ecological safety problem and protection from exposure to dust, depend
much on the equipment and techniques used in quarrying the brown coal. Thus, dynamics of
loading the open cast colliery dump trucks which have a load-carrying capacity of hundreds of
tons, mass of tens of tons and dimensions of tens of meters, is a very important problem. The
numerical results of free and forced vibrations problems of the complex system with the elastic
and visco-elastic inertial interlayer, for various parameters and different modes of dynamical
loading, are given in this paper.
Contents
- E. Włodarczyk:
Normal penetration of the rigid penetrator into elastic-plastic half-space with viscosity
- The analytical closed-form solution of the normal penetration problem of a rigid core
(penetrator) of a jacket-bullet into elastic-plastic half-space (thick target) is presented in this
paper. The cohesive resistance of the target, frictional effects, and acceleration of the target
material in the neghbourhood of the penetrator (virtual mass effect) is taken into consideration.
On the basis of the derived closed analytical formulae, influence of these parameters on the
penetration depth may be investigated. Among other things, it appears from calculations that
the boundary penetration depth is intensivly reduced by the force of viscous friction.
- Moreover, the mean value of the coefficient of viscous friction (μ) for a given penetrator-target
system may be determined. For this purpose it is necessary to define experimentally the
penetration depth hk at a given impact velocity.
Contents
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