### Contents of Journal of Mechanical Engineering *54,* 2 (2003)

LI, Y., LEONG, S. H.: A CMAC neural network approach to redundant manipulator
kinematics control 65
ROBBE, M.-F., SARDAIN, P.: Comparison of several simplified models and
scenarios to simulate a steam explosion in a tank 82
MATSUDA, T., SATO, M.: Development of torsional damper with crowd of solid
balls for engine crankshaft 101
PLESEK, J., HOSCHL, C.: Consistent explanation of an apparent paradox in
thermo-elasticity theory (in Czech) 111
KUDLICKA, J.: Energy flow of elastic waves in a composite (in Slovak) 119

# Abstracts

###
A CMAC neural network approach to redundant manipulator kinematics
control

YANGMIN LI, SIO HONG LEONG

This paper studies the inverse kinematics issue of redundant manipulators
using the neural network method. The conventional method of solving this
problem
analytically is by applying the Jacobian Pseudoinverse Algorithm. It is
effective and able to resolve the redundancy for additional constraints.
However, its demand for computational effort makes it not suitable for
real-time control. Recently, neural networks have been widely used in
robotic control because they are fast, fault-tolerant and able to learn. In
this paper, the CMAC (Cerebellar Model Articulation Controller) neural
network for solving the inverse kinematics problems in real time is
presented. Simulations have shown that the CMAC neural network has good
performance in tackling the inverse kinematics control of redundant
manipulators.

###
Comparison of several simplified models and scenarios to simulate a steam
explosion in a tank

MARIE-FRANCE ROBBE, PIERRE SARDAIN

A fuel-coolant interaction is one of the phenomena to be considered in the
frame of the safety analysis of experiments involving a molten metal and a
cold fluid. The interaction between a hot molten metal and a cold liquid
contained into a tank can lead to a short and high over-pressurisation which
can challenge the integrity of the tank. As the over-pressurisation depends
much on the accident conditions, it is essential to compare the influence of
different scenarios envisaged for this kind of accident. Simplified
one-dimensional numerical tools were used to have the opportunity to compute
several accident scenarios in a limited computation time.

###
Development of torsional damper with crowd of solid balls for engine crankshaft

TAKASHI MATSUDA, MOTOHIRO SATO

In this paper, new torsional damper is developed in order to improve the
defects of known dampers such as rubber dampers, oil dampers and solid
frictional dampers, which are used for vibration reduction of crankshafts in
most of reciprocating engines for automobiles. The damper is designed and
manufactured, and the experiments on the vibration reduction are carried out.
As a result, it is suggested that those defects can be improved by this
experimental damper, and that the effective damping is achieved by the new
damping mechanism, that is, the fluctuation of the natural frequency of
testing crankshaft system caused by alternating between the angular sliding
and the coupling of damper mass to the damper casing in every period of the
torsional vibration of the crankshaft.

###
Consistent explanation of an apparent paradox in thermoelasticity theory

JIRI PLESEK, CYRIL HOSCHL

A paradox involving a thermoelastic helical spring device was discussed in
literature. The spring is heated then loaded with the aid of the heat and
mechanical energy supply. Subsequently, the spring is cooled to the initial
temperature and unloaded, which brings the device back to its initial
thermodynamic state. The energy balance performed on the closed cycle
seemingly reveals a leftover of mechanical energy gained by the dilatation
during the cooling stage. This paper shows that the explanation suggested
in the cited reference is unsatisfactory since it disregards the effect of
thermoelastic coupling - a simplifying assumption often made in engineering
practice. Instead, a new solution is proposed in which the coupling term plays
a crucial role.

###
Energy flow of elastic waves in a composite

JAN KUDLICKA

Energy flow of elastic waves in an epoxy matrix composite reinforced by
continual boron fibres is investigated. For this anisotropic material, mean
values of the energy flow densities for axisymmetric elastic waves in a hollow
cylinder as functions of the radial co-ordinate and the wave number are
determined. The results for selected wave numbers and phase velocities from
the basic dispersion curve are compared with those obtained for an isotropic
epoxy cylinder.