Matériau | EPFL Graph Search

vignette|Grandes classes de matériaux. Les matériaux minéraux sont des roches, des céramiques ou des verres. Les matériaux métalliques sont des métaux ou des alliages. Un matériau est toute matière utilisée pour réaliser un objet au sens large. Ce dernier est souvent une pièce d'un sous-ensemble. C'est donc une matière sélectionnée à l'origine en raison de propriétés particulières et mise en œuvre en vue d'un usage spécifique. La nature chimique, la forme physique (phases en présence, granulométrie et forme des particules, par exemple), l'état de surface des différentes matières premières, qui sont à la base des matériaux, leur confèrent des propriétés particulières. On distingue ainsi quatre grandes familles de matériaux. En science des matériaux, par exemple, « matériau » est un terme générique employé dans le sens de matière, substance, produit, solide, corps, structure, liquide, fluide, échantillon, éprouvette, et désignant notamment l'eau, l'air, et le sable (dans des tableaux de

Mechanical and environmental assessment of Biobricks material

Enio Daniel Zanchetta

Microbial-induced calcite precipitation is a biochemical process of biomineralization. The process form mineral crystals composed of calcium carbonate and if precipitated into a sand matrix can lead to the formation of sandstone. The sandstone created in such way has the advantage of using a low amount of energy and even sequestrating CO2. This study aimed at comparing the environmental benefit of this material compared to classical building materials. The mechanical characteristics of the material were also assessed to have a first insight of the possible future applications as building material. X-ray computed tomography was conducted to assess the microstructural parameters of this material called “Biobricks”. Mechanical tests were performed and possible links between microstructure and strength evaluated. A life cycled assessment was conducted in a second part to quantify the environmental benefits of the material.

2018

The development of material-adapted structural form

Sean Dooley

New structural materials can potentially change the technics and economics of the building and construction industry in a profound way. It is important to identify applications and develop forms that exploit a material's unique properties. The developer of a material can use the knowledge of how materials such as steel and reinforced concrete were first introduced to advance the development and application of new materials today. This project examines why structural forms have evolved as they have and what influences the process of creating form, or form-finding. The purpose of this analysis is to aid the development of structural forms that make the most efficient use of material and take advantage of a material's processing and constructive attributes. Such forms are called material-adapted. This thesis is based on the general history of structural materials used in construction. This research is summarized in six appended case studies that comprise the data of the thesis. The research has extended well beyond these case studies; some of this data is included in the main text. The research showed that the influences on form-finding are: Function; Material Properties; Processing Technologies; Connection Technology; Construction Process; Economics; Socio- Political Factors; Knowledge; and Technological Thought. A Form-Finding Influence Interaction Model summarizes the inter-relationships of these influences. It was first assumed that material-adapted form is determined by material properties alone. Further research showed this untrue. The hypothesis of this thesis is that material properties do not unilaterally determine material-adapted structural form. This statement is true because the nature of a material is a function of its properties and its processing and constructive attributes. A material's processing and constructive attributes are dependent on technology and organizational systems that are not specific to the material. It was further hypothesized that new materials are first used substitutionally in forms and applications of known materials. This concept was found to be misleading and untrue for a number of materials. The knowledge of this thesis was used to examine the current development of fiber reinforced polymer composite materials. It is shown that a material's development can be analyzed not only by the aforementioned influences, but also by characteristics of other material developments. This information is used to suggest how these materials might develop in the future.

EPFL2004

Exploration of auxetics materials in sport

Thibault Antoine Marie Joseph Ghesquière-Diérickx, Nicolas Tireford

A special property of auxetic materials is their negative Poisson’s ratio : this material shortens or lengthen in all directions when subjected respectively to a compressive or tensile force. This unusual characteristic opens up new perspectives in many fields. Sport is one of the fields where these properties can be well exploited. Already studied and already used for protective equipment, their properties could also prove themselves useful with other application such as grips. The goal of this paper is to study the properties of a sole cell, modelled to exhibit the auxetic behaviour, although the material itself is not auxetic. 3D modelling will allow both parametric finite element studies and the possibility of making 3D prints for testing friction especially.

2021

The development of material-adapted structural form

Sean Dooley

EPFL2004