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Quasi-static and dynamic properties of the intervertebral disc : experimental study and model parameter determination for the porcine lumbar motion segment

Araujo A. R. G., Peixinho N., Pinho A. C. M., Claro J. C. P.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

59--66

EN

Purpose: The study of axial loading is essential to determine the properties of intervertebral disc. The objectives of this work are (1) to quantify the mechanical properties of porcine lumbar intervertebral discs under static and cyclic compressive loading, and (2) to determine the parameters of a five-parameter rheological model for porcine and compare them with those obtained for human lumbar intervertebral discs. Methods: Thus, the porcine lumbar motion segments were subjected to quasi-static and dynamic compression tests. The quasi-static tests were used to obtain the static stiffness coefficient at different strain rates, while the data from the cyclic compressive tests were used to both determine the dynamic stiffness coefficient and to be fitted in a 5-parameter model, in order to simulate the creep response of the porcine intervertebral discs. Results: The results demonstrated that dynamic stiffness coefficient of porcine discs is between four and ten times higher than the static stiffness coefficient, depending on load applied. The parameters of the rheological model suggested a low permeability of nucleus and endplate during the fast response of porcine discs. In addition, the fast response in terms of displacement is four times higher than those documented for human discs. Conclusions: This study revealed that care must be taken on the comparison between porcine and human discs, since they present different behaviour under quasi-static and dynamic compressive loading.

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The dynamic response of an elastic background under undetermined variable loads

Ossowski A.

Vibrations in Physical Systems

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2008

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Vol. 23

309--314

EN

The problem of Lagrange stability of an elastic background excited by undetermined variable loads is considered. A discrete model of the background with bounded excitations is studied. Applying optimal Lyapunov functions, upper bounds on the dynamic response of the background are estimated and interpreted in terms of rough sets. The described approach is useful to estimate vibration transmission in ground as well as to analyze vibration of a road surface or rail-track loaded by moving vehicles.

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O sposobach identyfikacji wytężenia dynamicznego stropów

Mironowicz W., Sęk M.

Inżynieria i Budownictwo

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2008

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R. 64, nr 10

570-572

PL

W analizach uwzględniono obszerne badania własne, wyniki pomiarów i nawiązano do zaleceń literaturowych. Omówiono różne sposoby określania rzeczywistego wytężenia dynamicznego istniejących użytkowanych stropów.

EN

Analysis presented here includes an extensive investigations made by the author, measurement results and recommendations from the existing literature. Different methods of the determination of the real dynamic response of slabs in serviced buildings are described.

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Niektóre problemy dynamiki stropów przemysłowych

Mironowicz W., Sęk M.

Inżynieria i Budownictwo

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2006

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R. 62, nr 1

29-31

PL

Na podstawie wieloletnich badań własnych i w nawiązaniu do zaleceń literaturowych przedstawiono problemy dynamicznej pracy dwóch rodzajów stropów przemysłowych obciążonych maszynami. Omówiono też możliwość identyfikacji wytężenia dynamicznego elementów stropów w przypadkach, gdy bezpośredni pomiar jest utrudniony lub niemożliwy.

EN

On the base of autor's own multi-years investigation the problem of dynamic behaviour of two kinds of industry floors loaded with machinery has been presented. The possibility of identification dynamic efforts of the floor units in case when the direct measurement is difficult or impossible has been indicated.