Contents of Journal of Mechanical Engineering 60, 4 (2009)


OKROUHLÍK, M., PTÁK, S., LUNDBERG, B., VALDEK, U.: FE assessment 
of an experiment employed for analysis of the transient stress 
energy flux through spiral slots in axially impacted cylindrical 
tube                                                                    181

MATES, M., NYEKY, D., HONEK, M.,ROHAĽ-ILKIV, B.: Control of 
inverted pendulum laboratory system using stepper motor                 211

BERI, N., MAHESHWARI, S., SHARMA, CH., KUMAR, A.: Parametric 
optimisation of electrical discharge machining of EN-19 using 
response surface methodology                                            221

Abstracts

FE assessment of an experiment employed for analysis of the transient stress energy flux through spiral slots in axially impacted cylindrical tube

MILOSLAV OKROUHLÍK, SVATOPLUK PTÁK, BENGT LUNDBERG, URMAS VALDEK

The temporal and spatial distribution of the stress wave energy flux in an axially impacted cylindrical tube, whose middle part contains four spiral slots, is studied experimentally and numerically. The high-speed recording of transient surface strains was used in the experiment, while the 3D finite element treatment was employed for the numerical analysis. The aim of the paper is to ascertain how reliable is the energy assessment based on transient recordings of surface strains and on subsequent 1D wave theory reasoning. The presented paper quantitatively determines how much of the impact energy, which is predominantly of axial (longitudinal) nature, is transferred into torsional (or shear) energy mode as well as to other energy modes not seen by the experiment.

Control of inverted pendulum laboratory system using stepper motor

MIROSLAV MATES, DANIEL NYEKY, MAREK HONEK, BORIS ROHAĽ-ILKIV

The problem of the balancing inverted pendulum by moving the pivot horizontally on a carriage is commonly used in mechatronics systems education to illustrate difficulties in controlling a mechanical plant having unstable open-loop poles. This paper presents some experiences with one type of linear quadratic (LQ) controller for stabilizing the pendulum powered with stepper motor. The problem of raising the pendulum from its stable equilibrium state to its unstable equilibrium state is solved using constraints on horizontal movement of the carriage. The experimental results are reported.

Parametric optimisation of electrical discharge machining of EN-19 using response surface methodology

NAVEEN BERI, SACHIN MAHESHWARI, CHITRA SHARMA, ANIL KUMAR

Electric discharge machining (EDM) is a non-contact machining process, which is controlled by a number of machining parameters. In the present work an attempt has been made to optimise the effect of input parameters, viz. current, flushing pressure and electrode size with straight polarity on process output parameters, viz. material removal rate (MRR) and surface roughness (SR). Experiments were conducted on EN-19 using copper electrode in commercial grade kerosene as dielectric fluid. Experiments were planned and analysed using response surface methodology (RSM). Increase in MRR is observed with increase in electrode size, current and flushing pressure. SR increases with increase in current and electrode size.