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1

Surface Green’s function of a soft elastomer with the gravity effect

Liang Xiaodong, Liu Junxiu, Xu Peibao, Li Kai

Journal of Theoretical and Applied Mechanics

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2020

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Vol. 58 nr 1

35--44

EN

Gravity can play a tremendous effect on deformation of rubberlike materials and biological soft tissues. In this paper, considering the gravity effect, we proposed a surface Green’s function of a soft elastomer based on the neo-Hookean model. The proposed surface Green’s function is applied to analyze the elastic deformation of a soft elastomer subjected to uniform pressure. The surface normal displacement of the soft elastomer is calculated and the results show that gravity has a large impact on the surface deformation of the elastomer. Generally, the surface normal displacement decreases with the increasing gravitational force.

2

Analysis of the possibility of assessing the ability to strengthen of the selected materials in the study indentation

Makuch A., Grygiel D.

Inżynieria Powierzchni

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2016

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nr 3

39--44

EN

This work undertakes the problem of the possibility of assessing the ability to strengthen of the materials with very different hardness, i.e. copper, ordinary steel, silicon carbide and zirconium oxide. Measurements of parameters of hardness and elasticity by means of the DSI method were conducted under constant conditions of the indentation process of Vickers indenter into the sample material. On the basis of the curves of power P-h (loading/unloading power as the function of depth) the work of elastic, inelastic and total deformation was determined, and then the coefficient k, which is postulated in Oliver Pharr's works as a measure of the ability of materials to strengthen, was determined.

PL

W pracy podjęto problem możliwości oceny zdolności do umocnienia materiałów o bardzo zróżnicowanej twardości, tj. miedzi, stali zwyklej, węglika krzemu i tlenku cyrkonu. Wykonano pomiary parametrów twardości i sprężystości metodą DSI przy stałych warunkach procesu zagłębiania się wgłębnika Vickersa w próbki materiału. Na podstawie krzywych energetycznych P-h (silą obciążania/odciążania w funkcji głębokości) wyznaczono pracę odkształcenia sprężystego, niesprężystego, całkowitego, a następnie wyznaczono wskaźnik k, który jest postulowany w pracach Oliviera-Pharra jako miara zdolności do umocnienia materiałów.

3

Rapid machining with industrial robot

Kampa A., Gołda G.

Selected Engineering Problems

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2014

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nr 5

57--62

EN

Industrial robots are used for many tasks, mainly for material handling and welding. Robots can be also equipped with other tools and used for machining. Nowadays small numbers of robots are used mainly for machining of soft materials, such as plastic, wood, foam and aluminium. This technique is used mainly for rapid prototyping. In this article an example of computer modelling of robotic cell for machining is shown. Some problems related with robot programming, accuracy, repeatability and calibration are discussed. An example of machining in polystyrene is presented.

4

Governing Differential Equations for the Mechanics of Undamageable Materials

Voyiadjis G. Z., Kattan P. I.

Engineering Transactions

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2014

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Vol. 62, iss. 3

241–-267

EN

In this work the mathematical foundations of the mechanics of elastic undamageable materials are presented. In particular the governing differential equations are derived for both the scalar and tensorial cases. In the isotropic case it is found that the resulting scalar differential equations are simple and easy to solve. However, in the anisotropic case the tensorial differential equations are complicated and unsolvable at this time. The current work presents the solution in the form of explicit nonlinear stress-strain relations for the simple one-dimensional case. However, the general solution of the three-dimensional case remains unattainable at the present time. Only the governing tensorial differential equations are derived for this latter case. It is to be noted that the term “undamageable” is reflected in the context of the material stiffness and not the property of indestructibility due to various loading conditions. Thus, the undamageable material reflects that no microcracks or microvoids occur as well as no plastic yielding in the material. To illustrate this concept, a last section is added on applications.

5

The numerical verification of the bending composite model

Kobza W.

Zeszyty Naukowe. Włókiennictwo / Politechnika Łódzka

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2000

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z. 58

79-87

EN

The classical theory of bending neglects the interaction between longitudinal layers and assumes their constant thickness independently of the magnitude of load. The theory is successfully applied for isotropic materials. In this work the model of bending multilayers composites materials filled with soft materiais such as for example honeycomb, porous materials or distance textile is described. The bending layers are compressed in transverse direction and theirs thickness and stiffness of bending decrease. The model of bending is numerically verified using an energetic finite element method.