Epimers with distinct mechanical behaviours

This article presents a novel bistable structural element that has high stiffness in stable configurations, but requires only a small amount of energy to be switched from one configuration to the other. The element is based on a planar linkage of four bars connected by revolute joints, braced by tape-spring diagonals. A description of the concept is presented, along with a detailed theoretical analysis of its mechanical behaviour. Experimental measurements obtained from a prototype structure are found to be in very good agreement with the predictions from this analytical model.

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Big influence of small random imperfections in origami-based metamaterials

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2020.0236 ◽

2020 ◽

Vol 476 (2241) ◽

pp. 20200236

Author(s):

Ke Liu ◽

Larissa S. Novelino ◽

Paolo Gardoni ◽

Glaucio H. Paulino

Keyword(s):

Numerical Simulations ◽

Mechanical Behaviour ◽

The Other ◽

Basic Pattern ◽

Geometric Imperfections ◽

Compressive Stiffness ◽

Compressive Response ◽

Other Hand

Origami structures demonstrate great theoretical potential for creating metamaterials with exotic properties. However, there is a lack of understanding of how imperfections influence the mechanical behaviour of origami-based metamaterials, which, in practice, are inevitable. For conventional materials, imperfection plays a profound role in shaping their behaviour. Thus, this paper investigates the influence of small random geometric imperfections on the nonlinear compressive response of the representative Miura-ori, which serves as the basic pattern for many metamaterial designs. Experiments and numerical simulations are used to demonstrate quantitatively how geometric imperfections hinder the foldability of the Miura-ori, but on the other hand, increase its compressive stiffness. This leads to the discovery that the residual of an origami foldability constraint, given by the Kawasaki theorem, correlates with the increase of stiffness of imperfect origami-based metamaterials. This observation might be generalizable to other flat-foldable patterns, in which we address deviations from the zero residual of the perfect pattern; and to non-flat-foldable patterns, in which we would address deviations from a finite residual.

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Analysis of the Thermo-Mechanical Behaviour of Steel-to-Timber Connections in Bending

Journal of Structural Fire Engineering ◽

10.1260/2040-2317.5.2.97 ◽

2014 ◽

Vol 5 (2) ◽

pp. 97-112 ◽

Cited By ~ 2

Author(s):

Dhionis Dhima ◽

Maxime Audebert ◽

Abdelhamid Bouchaïr

Keyword(s):

Mechanical Behaviour ◽

Yield Criterion ◽

Element Model ◽

Fire Tests ◽

Fire Exposure ◽

Mechanical Behaviours ◽

Timber Connections ◽

The Hill ◽

Temperature Time ◽

Good Agreement

Two different configurations of steel-to-timber connections are tested in bending in normal conditions and under ISO-fire exposure. To observe the influence of clearances in the connection area on the fire resistance of the connections, two specimens were previously tested under cyclic loadings. These tests consist in the application of loading-unloading cycles by controlled displacements. The experimental results of connections tested in cold and under ISO-fire conditions are analyzed and commented. These results are then used to validate a finite element model. This model allows to simulate numerically the evolution of the temperatures inside the connections as well as their mechanical and thermo-mechanical behaviours. The thermal modelling is validated on the basis of the temperature-time evolutions measured during fire tests. The nonlinear modelling of the mechanical behaviour of timber is done using the Hill yield criterion in combination with the Tsaï-Wu failure criterion. The thermo-mechanical modelling allows obtaining fire resistances of the tested connections in good agreement with the experimental ones.

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Mechanical Behaviour of Host Rock Close to H.L.W. Disposal Cavities in a Deep Granitic Formation

MRS Proceedings ◽

10.1557/proc-50-791 ◽

1985 ◽

Vol 50 ◽

Author(s):

J. M. Hoorelbeke ◽

M. Dourthe

Keyword(s):

Experimental Study ◽

Mechanical Behaviour ◽

Three Dimensional ◽

Failure Criteria ◽

The Other ◽

Analytical Models ◽

Finite Element Models ◽

Clear Indication ◽

The One ◽

Mechanical Disturbances

AbstractThe construction of a H.L.W. repository in a deep granitic formation creates mechanical disturbances in the rock on the scale of the massif and in the nearfield. Amongst all the disturbances noted in the nearfield, this study is concerned with examining the evolution of stresses linked with the excavation of the rock and the rise in temperature in the proximity of the waste packages. Several linear elasticity calculations were made using on the one hand finite element models and on the other simple analytical models. These calculations concern two different storage concepts -“in room” concept and “in floor” concept- whose differences in mechanical behaviour are analysed. A study of sensitivity with regard to the characteristics of the rock and to the initial geostatic stresses is presented. The comparison of the calculated stresses with three-dimensional failure criteria gives a clear indication of the satisfactory behaviour of granite for final storage. However, the need for experimental study and complementary calculation must be emphasised.

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Wear and Seizure of Aluminium-Silicon Piston Alloys in Reciprocating Motion against Steel

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/pime_proc_1995_209_439_02 ◽

1995 ◽

Vol 209 (4) ◽

pp. 287-296 ◽

Cited By ~ 2

Author(s):

A Somi Reddy ◽

K S S Murthy ◽

S K Biswas

Keyword(s):

Mechanical Behaviour ◽

Pressure Range ◽

Normal Pressure ◽

Strain Rate Range ◽

The Other ◽

Qualitative Model ◽

Reciprocating Motion ◽

Rate Range ◽

Alloying Additions ◽

Speed Range

Aluminium-silicon alloy pins were dry slid in unidirectional and reciprocating sliding against steel counterfaces in a normal pressure range of 0.39–26 M Pa and a sliding speed range of 0.6–1.8 m/s. Changing the mode of sliding from unidirectional to reciprocating as well as an increase in reciprocating speed were found to affect wear and seizure resistances adversely. Alloying additions of copper and magnesium to the base metal, on the other hand, were found to improve both of these properties. The temperature rise of the pin during sliding and the mechanical behaviour of the test alloys in compression in a temperature range of 25 300 °C and a strain rate range of 0.1–100/s were recorded and the data incorporated into a qualitative model to account for the wear and seizure behaviour of the test materials.

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Mechanical Behaviour of Common Bean (cv. Butter) Seeds as Affected by Maturation

Journal of Engineering Research and Reports ◽

10.9734/jerr/2019/v8i216989 ◽

2019 ◽

pp. 1-12

Author(s):

H. Uguru ◽

O. I. Akpokodje ◽

S. V. Irtwange

Keyword(s):

Common Bean ◽

Mechanical Behaviour ◽

Maturity Stage ◽

Mechanical Parameters ◽

Rupture Force ◽

Maturity Stages ◽

Rupture Energy ◽

Mechanical Behaviours ◽

The Mean ◽

Least Energy

In this study, the effects of maturation of bean seeds on some mechanical behaviours of common bean (cv. Butter) were investigated. The bean seeds were harvested at three maturity stages (15 DAPA, 22 DAPA and 29 DAPA), and their rupture force, rupture energy, specific deformation, toughness and rupture power were test. The bean seeds were quasi-statically loaded in along their three main axes (X-axis, Y-axis and Z-axis), at a loading speed of 25 mm/min. The results obtained revealed that the maturity stage and loading orientation had significant (p ≤0.05) effect on all the mechanical parameters investigated in this study. According to the results, all the parameters investigated increased linearly as the bean seeds matured from 15 DAPA to 29 DAPA. For all the mechanical parameters, the highest values were obtained when the seeds were compressed along the Z-axis, while the least values were obtained when the seeds were compressed along the Y-axis. The highest rupture energy (0.064 Nm) was obtained for bean seeds (harvested at 29 DAPA) loaded along the Z-axis, while the bean seeds harvested at 15 DAPA and loaded along the Y-axis required the least energy to rupture (0.028 Nm). From the results, at 29 DAPA, the mean rupture power of 0.277 W, 0.212 W, and 0.314 W were recorded, when the seeds were compressed along the X-axis, Y-axis and Z-axis respectively. These results will be useful in the design and development of bean seeds processing and handling equipment.

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New Plaster Composite with Mineral Wool Fibres from CDW Recycling

Advances in Materials Science and Engineering ◽

10.1155/2015/854192 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

Sonia Romaniega Piñeiro ◽

Mercedes del Río Merino ◽

Cristina Pérez García

Keyword(s):

Mechanical Behaviour ◽

Mineral Wool ◽

The Other ◽

Construction And Demolition Waste ◽

Building Sector ◽

Demolition Waste ◽

Building Insulation ◽

New Construction ◽

Intense Activity ◽

Construction Works

Over the last decade the intense activity of the building sector has generated large quantities of construction and demolition waste (CDW). In particular, in Europe around 890 million tons of CDW is generated every year; however, only 50% of them are recycled. In Spain, over the last years 40 millions of tons of construction and demolition waste have been generated. On the other hand, since the implementation of the Technical Building Code regulation the use of mineral wools as building insulation materials has become a widespread solution in both rehabilitation and new construction works, and because of that, this kind of insulation waste is increasing. This research analyzes the potential of a new composite (gypsum and fiber waste) including several mineral wools waste into a plaster matrix. For this purpose, an experimental plan, characterizing the physical and mechanical behaviour as well as the Shore C hardness of the new composite, was elaborated fulfilling UNE Standards.

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The geometrical description of linear and simple planar features in soils

Soil Research ◽

10.1071/sr9670021 ◽

1967 ◽

Vol 5 (1) ◽

pp. 21 ◽

Cited By ~ 10

Author(s):

DR Willoughby

Keyword(s):

Root System ◽

Mechanical Behaviour ◽

Spatial Orientation ◽

Graphical Method ◽

Plant Root ◽

The Other ◽

Geometrical Description ◽

Plant Root System

A quantitative graphical method of describing the spatial orientation of all linear and planar features in soils is presented. The method is then applied, on two black earth samples, to obtain solutions for planar particles and planar pores in one soil, and the plant root system and planar pores in the other. The solutions from each of these components are not only suitable for comparison with each other but, more importantly, are an expression of certain aspects of soil mechanical behaviour.

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Micromechanical Analysis of the Fibre-Reinforced-Epoxy Composites with Nanoparticles Embedded in the Interphase Region under Transverse Compression

Advanced Composites Letters ◽

10.1177/096369351802700304 ◽

2018 ◽

Vol 27 (3) ◽

pp. 096369351802700

Author(s):

Zhen-Qing Wang ◽

Hao Li ◽

Xiao-Yu Sun

Keyword(s):

Mechanical Behaviour ◽

Volume Fraction ◽

Young Modulus ◽

Deformation Energy ◽

Matrix Composites ◽

Transverse Compression ◽

Element Analysis ◽

Mechanical Behaviours ◽

Strain Relationship ◽

Distribution Type

The mechanical behaviours of fibre reinforced epoxy matrix composites with silica nanoparticles inserted between fibres and matrix subjected to transverse compression are studied by computational micromechanics. A series of representative volume elements of composite microstructures containing fibres, nanoparticles with different distribution types, volume fractions and Young’ modulus; and matrix are established. The effect of nanoparticles incorporated in the interfacial phase on the elastic-plastic behaviour of composites has been assessed. The stress versus strain relationship, ductility and compressive strength are determined by the finite element analysis. It is found that the material property, volume fraction and distribution type of nanoparticles have significant influences on the mechanical behaviour of composites. The large plastic deformation between the fibre and nanoparticles can consume considerable deformation energy, which will enhance the mechanical behaviour of composites.

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Shifting from meaning to its carrier: A common denominator for three strains of humour

European Journal of Humour Research ◽

10.7592/ejhr2018.6.3.aharoni ◽

2018 ◽

Vol 6 (3) ◽

pp. 13 ◽

Cited By ~ 1

Author(s):

Ron Aharoni

Keyword(s):

Mechanical Behaviour ◽

General Type ◽

The Other ◽

Common Denominator ◽

The Core ◽

Human Reaction ◽

The Subject ◽

Self Reference

Incongruity theories maintain that the core of humour is in interplay between meanings. Two incompatible meanings – of situations, verbal utterances or actions – are juxtaposed, one replacing the other or colliding with it. In this paper, I suggest that often the game is not played between two meanings, but between meaning and its carrier. I provide as examples two families of jokes and one general type of humour sharing this mechanism. One of the two families comprises jokes of self-reference, and the other consists of jokes based on deflation of symbols, which means using them in a concrete sense. The general type of humour is the subject of Bergson’s 1900 theory of the comic, mechanical behaviour where flexible human reaction is expected. The mechanism common to all three is a shift of weight from meaning to its carrier. This mechanism is then traced also in other jokes, suggesting possible universality

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