Contents of Journal of Mechanical Engineering 55, 5 (2004)


HOSCHL, C.: Admissibility of mathematical models in the theory of parametric vibrations of spur gears (in Czech) 251 ROBBE, M-F., CHRISTOPHE IMBERT, CH., LASSABATERE, T., CANY, F.: Saturation process of a storage cell of a high-level radwaste repository 259 KLIMAN, V., JAROSI, M.: System of continuous assessment of structure fatigue reliability. Part II. Application experiment (in Slovak) 293 KROPAC, O., MUCKA, P.: Estimation of road waviness using the IRI algorithm 308


Abstracts



Admissibility of mathematical models in the theory of parametric vibrations of spur gears

CYRIL HOSCHL

A simple system of gears with variable number of teeth in mesh was studied by many authors. Mathematical models of such a system are necessarily based on several simplifying assumptions. It may happen that the model violates certain physical law. The author gives an example of such a model which was unsatisfactorily discussed in the recently published literature. The sources of the misapprehensions are clarified in the paper. The remedy lies in adding a new inner non-tangential reaction which acts only at the moment of changing the number of pairs of matching teeth, i.e., during the irregular edge contact of teeth. This reaction forces the tooth of one gear to slide into the reduced gap between the teeth of the other gear. Simultaneously, it transports the missing energy into the system so that both the Newton's third law as well as the energy conservation law are satisfied.


Saturation process of a storage cell of a high-level radwaste repository

MARIE-FRANCE ROBBE, CHRISTOPHE IMBERT, THIERRY LASSABATERE, FRANCOIS CANY

In France, the concept of repository for high-level long-lived radioactive waste is based on a set of underground galleries connected to disposal cells containing waste canisters. Cells are filled with an engineered barrier, and closed by a plug. The progressive hydration of the swelling clay of both barrier and plug by the interstitial water seals the gaps, and provides a global mechanical stability of the waste-clay barrier-plug-host rock system. This paper is devoted to the analysis of the barrier and plug saturation by the site water. Four configurations are examined. The evolution of pressure and saturation is analysed and compared globally on the full geometry, and locally along sections and at different points.


System of continuous assessment of structure fatigue reliability. Part II. Application experiment

VLADIMIR KLIMAN, MARIAN JAROSI

Part II of the paper is devoted to the experimental verification of the \linebreak methodology (proposed in Part I) of a continuous assessment of the state of structure in view of fatigue damage. For the purpose of fatigue damage monitoring the computer program has been elaborated which, on the base of a continuous measurement of the loading process at critical locations of the structure and inserted data on the material properties, enables to calculate and display in real time all the characteristics needed to assess the fatigue-reliability of the structure during its service. State of the structure after a certain time of its operation is characterized mainly by the value of remaining fatigue life and immediate probability of survival. Further parameters enabling to assess reliability of operation of the structure from the point of view of fatigue fracture occurrence are also monitored. The monitoring system proposed has been verified experimentally on the base of comparison of the theoretical and experimental function of survival probability of the test specimens under loading by the s(t) random loading process. A good agreement is proved. The factors influencing the fatigue-reliability parameters, obtained by the monitoring system, are also analysed.


Estimation of road waviness using the IRI algorithm

OLDRICH KROPAC, PETER MUCKA

The waviness of the road unevenness can be estimated from two values of the International Roughness Index (IRI) corresponding to two different running speeds. Consequently, both direct and inverse conversion relations between the IRI and parameters C and w of the power spectral density (PSD) of the road unevenness are applicable.