Contents of Journal of Mechanical Engineering 57, 3 (2006)

VALA, J.: Two-scale finite element techniques in engineering mechanics 127 SHARMA, V. S., SHARMA, S. K., SHARMA, A. K.: Tool wear estimation for turning operations 141 BEITHOU, N.: Geometric analysis of steam-driven jet pump 169 BEREZIN, S. Y., CHUMAKOV, R. E.: Structured system analysis for assembly automations 180


Two-scale finite element techniques in engineering mechanics


In the numerical analysis of many problems of engineering mechanics the same difficulty occurs: how to couple the information from material microstructural analysis with the macroscopic description of behaviour of the whole sample or structure, not to increase time and cost of calculations dramatically. The article demonstrates on a model problem how this difficulty can be overcome using the two-scale modification of the finite element and similar numerical techniques, based on certain special iterative algorithm. The error estimates and convergence results are followed by remarks and references to applications in mechanical and civil engineering.

Tool wear estimation for turning operations


The experimental investigation on cutting tool wear and a model for tool wear estimation is reported in this paper. The changes in the values of cutting forces, vibrations and acoustic emissions with cutting tool wear are recorded and analyzed. On the basis of experimental results a model is developed for tool wear estimation in turning operations using Adaptive Neuro-Fuzzy Inference System (ANFIS). Acoustic emission (Ring down count), vibrations (acceleration) and cutting forces along with time have been used to formulate a model. This model is capable of estimating the wear rate of the cutting tool. The wear estimation results obtained by the model are compared with the practical results and are presented. The model performed quite satisfactory results with the actual and predicted tool wear values. The model can also be used for estimating tool wear on-line but the accuracy of the model depends upon the proper training and section of data points.

Geometric analysis of steam-driven jet pump


The steam-driven jet pump (SDJP) is an engineering device that is consisting of a set of converging-diverging nozzles and diffusers. The SDJP is a device without moving parts and requires no external energy supply. Because of these passive features of the SDJP it is very attractive in next generation nuclear power plants, as a passive emergency core cooling system. In this study, a geometric analysis of SDJP is performed to investigate the effects of water nozzle area and overflow valve setting on the workability range of the SDJP. For the operation of the SDJP it is observed that there is an optimal overflow valve setting for each steam inlet pressure. In addition, for each range of the steam inlet pressure there is an optimal water nozzle area, which suggests the need of automatic control of both the overflow valve 2 and water nozzle area in relation with the steam inlet pressure.

Structured system analysis for assembly automations


The paper presents a new method to evaluate the complication of technological systems in assembly automations machines. Structure-parametrical model allows to analyse structural correlation in a technological system and to design assembly machines with optimum parameters.