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Najczęściej popełniane błędy podczas szacowania nośności opakowań z tektury falistej

Garbowski Tomasz

Przegląd Papierniczy

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2023

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R. 79, nr 9

485--488

PL

W pracy przedstawiono pokrótce główne błędy, które najczęściej pojawiają się w procesie szacowania nośności opakowań z tektury falistej. Wiążą się one z nieprawidłowym określeniem współczynników korygujących, zarówno tych poprawiających bezpieczeństwo poprzez zwiększenie wymaganej nośności, jak i tych, które wyraźnie obniżają parametry mechaniczne tektury falistej, a w konsekwencji wartość szacunkowej nośności opakowania z tektury falistej. Niezależnie od tego, jak ostatecznie jest weryfikowana nośność opakowania, prawidłowe oszacowanie współczynników bezpieczeństwa a także współczynników korygujących jest kluczowe w procesie dążenia do zrównoważonego rozwoju branży opakowań z tektury falistej.

EN

The work briefly shows the main errors that most often appear in the process of estimating the load-bearing capacity of corrugated board packaging. They are related to the incorrect determination of correction factors, both those that increase safety by increasing the required load-bearing capacity, and those that clearly reduce the mechanical parameters of corrugated board and, consequently, the value of the estimated load-bearing capacity of the packaging. Regardless of how the load-bearing capacity of the packaging is ultimately verified, the correct estimation of safety factors and correction factors is crucial in the process of achieving sustainable development of the corrugated packaging industry.

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Applanation pressure function in Goldmann tonometry and its correction

Śródka W.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 3

97--106

EN

So far applanation tonometry has not worked out any theoretical basis for correcting the result of intraocular pressure measurement carried out on a cornea with noncalibration dimensions by means of the Goldmann tonometer. All the tables of instrument reading corrections for cornea thickness or cornea curvature radius are based exclusively on measurements. This paper represents an attempt at creating a mechanical description of corneal apex deformation in Goldmann applanation tonometry. The functional dependence between intraocular pressure and the pressure exerted on the corneal apex by the tonometer was determined from a biomechanical model. Numerical GAT simulations, in which this function was also interrelated with the cornea’s curvature radius and thickness were run and a constitutive equation for applanation tonometry, i.e. a full analytical description of intraocular pressure as a function of the above variables, was derived on this basis. The correction factors were defined and an algorithm for correcting the measured pressure was formulated. The presented formalism puts the results of experimental tonometry in new light. Analytical correction factors need not to come exclusively from measurements. A geometric interdependence between them and their dependence on pressure have been revealed. The theoretical description of applanation tonometry contained in the constitutive equation consists of a pressure function developed for a cornea with calibration dimensions and a coefficient correcting this calibration function, dependent exclusively on the cornea’s actual thickness and curvature radius. The calibration function is a generalization of the Imbert–Fick law.

3

On the Identification of Dynamic Friction Material Properties under Brake Squeal Relevant Loading Conditions

Hornig S. A., Wagner U. v.

Machine Dynamics Research

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2012

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Vol. 36, No. 3

29-44

EN

Brake squeal is a disruptive high frequency noise generated by friction-induced self excited vibrations of the brake system. Great effort is spent on the improvement of brake squeal prediction reliability, using mathematical-mechanical simulation models. In this context friction material properties are one of the decisive factors for the successful brake squeal simulation. Because of the nonlinear and load dependent friction material behavior, it is mandatory to identify friction material properties under squeal typical loading conditions. For this reason a measurement method reproducing squeal typical operating conditions is under development by the authors’ research group. The present paper shows the actual development stage of this measuremet method, presenting the dynamic compression test rig, estimated friction material characteristics, and emphasizing important influence factors on the dynamic compression measurement results. In this context a particular focus is set on the derivation of correction factors when converting the measured stiffness of specimens with restriced dimensions and boundary conditions into material stiffness.