Jean-François Caron

Jean-François Caron
École des Ponts ParisTech · Navier Laboratory, Architected Materials and Strucures team

Pr. PhD
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About

175
Publications
43,834
Reads
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1,980
Citations
Citations since 2016
62 Research Items
1111 Citations
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Introduction
leader of the Architected Materials and Structures (MSA) department of the Navier Laboratory and is Professor at Ecole des Ponts Paristech. Modelling of multilayered structures and composites, and innovative composite structures. Member of the European working group for a composite Material Eurocode. Focuses also on digital construction, 3D printing and robot for construction. In charge of the project DiXite https://dixite.future-isite.fr/ and of Build'In Platform https://en.buildin-enpc.fr/
Additional affiliations
January 2000 - present
University of Paris-Est
Position
  • Research Director

Publications

Publications (175)
Article
Structures that are 3D printed by an extrusion process have periodic geometrical heterogeneity whose influence on the final stiffness properties is not extensively discussed in the existing literature. The objective of this article is to quantify the effect of local lace geometry on the anisotropy of extrusion-based 3d printed structures. A numeric...
Article
Full-text available
The detection of anomalies is at the basis of any 3D printing control. In this paper, we propose a methodology for detection of anomalies based on computer vision. This methodology is composed of three modules: (1) image acquisition, (2) interlayer line and layer segmentation and (3) characterization of the local geometry and texture of the layers...
Poster
Full-text available
Various technologies of in-line reinforcement for extrusion-based 3D printing have been proposed in the recent years. With such techniques, knowledge of the dynamic rheological properties of the extruded material is a key point for several issues, such as its ability to properly impregnate reinforcement, and possibly to pull the reinforcement thank...
Chapter
The issue of reinforcement for 3D concrete printing has received considerable attention, as constructions have to comply with reliability principles and building standards. Here a specific process called Flow-Based Pultrusion for additive manufacturing (FBP), inspired by pultruded composite manufacturing and built on existing extrusion-based 3D pri...
Chapter
The adoption of FRP materials for the construction of new bridges has become a challenge to traditional bridge engineers who need to become familiar with the materials itself but also with the code to design efficient FRP structures. Today, there is various available FRP design guidelines all around the world and in Europe, thus, the CEN/TC 250 sho...
Conference Paper
Full-text available
This study aims to design a topological interlocking structure which can be constructed without any formwork. According to studies, the cost of material and labour for formworks often consumes up to 50% of the total project cost (Hack et al)[1]. The construction industry, being one of the largest in the world economy with about 10 trillion USD (McK...
Article
This study was undertaken in the context of Cigéo project to investigate the use of geopolymer for potential applications in high level waste cell. The aim was to evaluate the structural evolution of potassium metakaolin based geopolymer as a function of time and temperature for geological nuclear waste disposal applications. The evolution of mecha...
Article
Important developments in additive manufacturing with concrete have been achieved in the past decades. Yet, printed components usually do not comply with building standards or basic reliability principles, and are not commonly used as load-bearing components. A gap between research and practice exists and despite several attempts, off-the-shelf com...
Article
This paper introduces a novel rheological technique allowing for the assessment of printable materials yield stress at nozzle exit in the case of extrusion-based 3D printing. This technique is derived from the analysis of the specific gravity-induced non-Newtonian flow that takes place at nozzle exit, which is at the origin of the formation of mate...
Article
An original experimental setup, dedicated to the measurement of the dynamic response of structures, is presented. Called the Robotized Laser Doppler Vibrometer (RLDV), it consists in the assembly of a fixed point Laser Doppler Vibrometer (LDV) on a 6-axis industrial robot arm. This allows to measure the 3D velocity on the surface of objects with a...
Article
Full-text available
This work aims at proposing a strategy for 3D-printing geopolymer composite structures at a half-meter scale, without using organic additives. An original printing device based on cartridges is developed and adapted to a 6-axis robot. The yield stress, working time and apparent Young modulus of the extruded material are measured. A devoted software...
Article
The vast majority of applications of extrusion-based concrete additive manufacturing deal with unreinforced mortar. The lack of reinforcement is a serious limitation for the industrial development of 3d printed concrete, because of the brittleness and lack of tensile strength of unreinforced mortar. In this paper, a new reinforcement method inspire...
Article
This work aims to synthetize geopolymer composites and study the influence of the aluminum concentration, wollastonite and glass fibers on the properties of the fresh and hardened material. To this end, different metakaolin, wollastonite and glass fibers contents were used to synthesize geopolymer composites. The effect of reinforcement elements on...
Article
This work aims to shape a hollow cylinder with a geopolymer and an additive manufacturing process (3D printing) without organic additives. The formulation of a geopolymer composite using only mineral parts is proposed and the parameters of the 3D printing process were optimized. The mechanical properties, the microstructure, and the adhesion of the...
Article
This work aims to adapt a formulation of a geopolymer composite to elaborate complex shapes. Here a hollow cylinder is chosen to investigate different possible solutions: building process according to the formulation. To this end, different content of metakaolin, wollastonite, and glass fibers was used to identify the feasibility of shaping of the...
Conference Paper
Full-text available
The embodied energy of a building is not only but essentially determined by the quantity of material in its structure. Current fabrication techniques of optimised reinforced concrete (RC) structural elements have not proved sufficient economic competitiveness to be broadly accepted by the construction industry. This partly explains why the construc...
Chapter
Successful and efficient fabrication using robotic extrusion of cementitious materials mainly relies on the mastering of the printable material fresh state behavior. This paper tackles this aspect by introducing a novel rheological apparatus dedicated to the yield stress measurement at nozzle exit in extrusion-based manufacturing. It is based on th...
Chapter
Full-text available
This paper proposes a specific extrusion method for 3D printing of mortar called free deposition by the authors. It consists in letting a fine mortar flow through a moving nozzle above a support, here EPS foam. The aim is to obtain a regular lace, thus to avoid instability phenomena like coiling, and ensure a regular diameter, without stretching th...
Article
The paper presents new results about the geometry of topological interlocking masonries and some possibilities they present to build without formwork. Construction without the use of formwork may be an important issue concerning both productivity increase and decreasing of waste generated on a construction site. Due to the development of computatio...
Article
For the last decades, new reparation or fabrication processes have been studied to replace traditional rebar by roving of different mineral or organic fibres to avoid corrosion issues. Such materials refer to the family of cementitious composite. Their tensile strength would directly depend on the proportion of reinforcement and strongly on the int...
Article
Full-text available
For the tens past years, important development has been achieved on the adaptation of additive manufacturing to the construction industry using concrete. They mostly concerns control rheology at fresh state, setting time, and technology advances. Nevertheless, the reinforcement of 3D printed part remains an open question. Different reinforcement pr...
Article
Full-text available
The goal of Zero Energy Buildings represents a challenge for designers: in order to meet required performance, a wide range of technologies and solutions is needed, and interactions with other stakeholders can limit productivity of building process. In this context, early-design stage plays a key role in building lifecycle: at this point, choices d...
Article
Full-text available
City revegetation strategies seem appealing to mitigate urban heat island effects through shading and transpirational cooling. Moreover, other potential benefits that may derive, e.g. biodiversity enhancement, the reduction in buildings energy consumption, stormwater management, acoustic insulation or air purification, earned them the designation ‘...
Article
Full-text available
The High Resolution Wavevector Analysis (HRWA) is presented and its application illustrated. Extending the High Resolution Wavenumber Analysis method [1] to 2D signals, it allows the wide-band and local characterization of the linear elastic behavior of anisotropic plates. The method belongs to the family of experimental wavenumber-based characteri...
Chapter
The aim of this paper is to discuss the dialectic form-finding of a complex timber structure based on an innovative structural system: shell-nexorade hybrids. Nexorades, also known as reciprocal frames are elegant structures that suffer from a relatively poor structural behavior due to in-plane shear and bending of the members. Introducing plates a...
Article
In the framework of sustainable development policies, it is essential that infrastructure owners can rely on effective repair or strengthening solutions, designed and tested in relevance to actual service conditions. In the case of steel structures, fatigue damage is a major concern that can significantly affect the lifespan of the structure, and s...
Article
The High-Resolution Wavenumber Analysis (HRWA) is presented. It identifies complex wavenumbers and amplitudes of waves composing the harmonic response of a beam. Based on the frequency dependence of these wavenumbers, experimental dispersion equations of various beam mechanisms (e.g bending, torsion) can be retrieved. The HRWA method is compared to...
Preprint
Full-text available
"Metal Euplectella Folie" is a prototype which explores an innovative design and manufacturing method for free-form architecture. Four 40m long by 0.4m wide by 1.5mm thick steel sheets, each cut to a unique pattern and then spiral-wrapped, form a sculptural tube assembled without the need for any adjustment, plans or jigs. This experimental constru...
Chapter
Full-text available
Navier laboratory, a joint research unit between the Ecole des Ponts ParisTech, IFSTTAR, and CNRS, gathers about 50 permanent scientists, 120 Ph.D.’s and general skills in the mechanics and physics of materials and structures, in geotechnics, and their applications to, in particular, civil engineering and petroleum geophysics. For last 15 years, Na...
Chapter
This study focuses on deployable systems actuated by shape memory alloys in the perspective of designing adaptive sun shading devices for building facades. We first set the context of smart materials for adaptive facades and underline the remarkable characteristics of shape memory alloys for mechanical actuation purposes. After outlining the constr...
Article
Adhesive joints are increasingly used in bridges and buildings construction thanks to their high mechanical properties and their ease of implementation. However, the load transfer mechanism within adhesive joints is complex and has been the subject of several studies since 1938. Several models have been developed to quantify the stress distribution...
Article
In the framework of sustainable development policies, it is essential that infrastructure owners can rely on effective repair or strengthening solutions, designed and tested in relevance to actual service conditions. In the case of steel structures, fatigue damage is a major concern that can significantly affect the lifespan of the structure, and s...
Conference Paper
Full-text available
p>By reinforcing the links between mechanics of materials, structural engineering and applied mathematics at a sufficiently high level, new paths may be explored and building innovations proposed, making complex structures more affordable constructions. Three main keys are explained and illustrated with examples. The first key is a deep knowledge o...
Conference Paper
p>“Metal Euplectella Folie” is a prototype which explores an innovative design and manufacturing method for free-form architecture. Four 40m long by 0.4m wide by 1.5mm thick steel sheets, each cut to a unique pattern and then spiral-wrapped, form a sculptural tube assembled without the need for any adjustment, plans or jigs. This experimental cons...
Article
Full-text available
In this paper phenomenological observations of the creep rupture under maintained combined traction and torsion loading are first presented. They show the importance of the matrix's behavior in the long-term durability of the material. Understanding and foreseeing creep rupture of unidirectional fiber reinforced polymers (UD FRP) involves comprehen...
Article
This study gives a detailed analysis on estimating the ultimate tensile strength of unidirectional fiber reinforced composites and its creep behavior under sustained tension load. We develop two different micromechanical models that allow us to estimate the longitudinal tensile strength and the evolution with time of fiber and matrix stresses aroun...
Article
Full-text available
Gridshells are lightweight structures made of interconnected slender beams. Due to large displacements, high interaction between the beams, and bending–torsion coupling, modeling gridshells requires specific non-linear numerical tools to reach convergence within a reasonable time. In this article, the development of such a tool is presented. It is...
Article
Full-text available
The aim of this paper is to present some innovative strategies for the design of plated shell structures. Fabrication constraints are carefully considered, as the obtained shapes are covered with planar quadrilateral facets only. Different corrugation strategies are investigated, and our method guarantees extension of the shape generation to comple...
Article
This paper proposes a new layerwise model for multilayered plates. The model, called SCLS1 for Statically Compatible Layerwise Stresses with first-order membrane stress approximations per layer in thickness direction, complies exactly with the 3D equilibrium equations and with the free-edge boundary conditions. As in the LS1 model initially propose...
Article
Full-text available
The Ephemeral Cathedral of Créteil at Paris, France, is a gridshell structure made of composite materials. Built in 2013, this 350 m2 religious edifice is a temporary church meant to gather the parishioners during the two year renovation of their permanent cathedral. This large-scale prototype represents a first in the building industry which still...
Technical Report
Full-text available
Over the last twenty years, many innovative solutions have confirmed the usefulness of composite structures realized with FRPs (Fibre Reinforced Polymer or Plastic). The need of European standards for use of fibre reinforced polymer composites in civil engineering was justified in 2007 in the JRC Report EUR 22864 EN. The new European technical rule...
Article
Clay-polymer nanocomposites were prepared by living free radical photopolymerization initiated from a lamellar clay-anchored photoiniferter resulting from a cation exchange reaction of sodium by diethyldithiocarbamate benzyldiazonium tetra-fluoroborate salt. The success of the cation exchange process, followed by iniferter graft polymerization of g...
Article
Full-text available
The design of free-form structures is governed by structural and geometric considerations, the latter ones being closely linked to the costs of fabrication. If some construction constraints have been studied extensively, the question of the repeatability of nodes in free-form structures has rarely been addressed yet. In this paper, a family of surf...
Article
Full-text available
The paper presents a completely novel approach to model elastic gridshells with a 4-DoF element based on recent advances in the field of hair modelling [1]. This element, based on Kirchhoff's beam theory, can account for both bending and torsion behaviours. The reduction from 6 to 4 degrees of freedom is achieved with an appropriate curve framing i...