David Crepin

David Crepin
Ecole d'ingénierie et d'innovation textile | ENSAIT

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28
Publications
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244
Citations

Publications

Publications (28)
Article
In an effort to increase junction toughness in foam core sandwich panels, improved designs of revolution inserts are detected through a simple energy approach. The main idea of this numerical study involves lowering the small-crack thermodynamic driving force using concepts of finite fracture mechanics and asymptotic expansion methods. For panels s...
Article
This paper presents a multi-scale model that can predict the ballistic impact behavior of multi-layer plain-woven fabrics using the finite element method (FEM). Multi-layer fabrics of 30.5×30.5 cm, woven by high performance yarns Kevlar 3000 denier, are impacted by a 0.3 fragment simulating projectile (FSP). Using a multi-scale approach, behavior o...
Article
Full-text available
In Phlebology, compression therapy is a widely used protocol either alone or in combination with other procedures. The goal of this article is to propose a summary of technical considerations which describe the phenomenon of interface pressure exerted on the skin by external compression provided by means of elastic materials. We focus our task only...
Conference Paper
The NUMTISS project aims at providing a numerical chain of simulation in order to obtain the more accurate geometry of a woven structure. This numerical chain is composed of three different parts: numerical simulation of the kinematic weaving process, numerical simulation of the Representative Elementary Volume of the weave diagram coupled with E-g...
Article
Full-text available
A weaving process simulation of fabrics, used as fibrous reinforcements in composite applications, is presented in this article. The mechanical modelling of textile structures requires an accurate geometric representation of the woven elementary cell including complex interlacements of yarns and compactions. Using an explicit finite element solver,...
Conference Paper
Full-text available
Due to advancements made in 3D weaving process and, in order to develop 3D textile structure as reinforcement of composite material for aeronautic application, a good prediction of the geometry and the mechanical properties of the 3D woven unit cell is required. The aim of the proposed study is to “numerically” mimic the motions of the main mechani...
Conference Paper
Full-text available
1 General Introduction The complexity of fibrous structures architectures (especially for 3D woven or braided preforms), used as reinforcements for composites in structural applications (mainly in aeronautics), leads to simulations performed at an elementary cell level (the so-called VER) [1, 2, 3, 4-6, 7, 8, 9]. Many studies have shown significan...
Conference Paper
Full-text available
This project is directly attached to the challenge in the aerospace industry to meet the new environmental requirements as the Kyoto Protocol [1]. One of the potential axis being explored through various national and European programs is the global reduction of the structure's mass when economic conditions are met. One of the mass reduction's solut...
Conference Paper
Full-text available
A good prediction of geometry and of the mechanical properties of the unit cell is necessary to develop 3D reinforcements in composite materials for aeronautical applications. There is a difficulty to get realistic geometries for these unit cells because of the complexity of these architectures. We can observe that existing tool which model 3D fabr...
Article
Due to advancements made in 3D weaving process and, in order to develop 3D textile structure as reinforcement of composite material for aeronautic application, a good prediction of the geometry and the mechanical properties of the 3D woven unit cell is required. The aim of the proposed study is to "numerically" mimic the motions of the main mechani...
Article
The goal of this article is to propose practical and scientific explanations about the mechanics of compression by the medical compression stocking (MCS) to the phlebologist and angiologist societies. The first part presents the principle of pressure generated by the MCS. We explain how the surface of MCS fabric is structured from the yarn scale an...
Conference Paper
A numerical model of ballistic impact on a 2D Kevlar KM2® plain-woven fabric has been validated by the experiment. This paper shows that it is necessary to experimentally measure material constants of yarns for having good input parameters of the model. Effects of yarn Poisson’s ratio, transverse and shear modulus on impact behaviors of a simple cr...
Article
A numerical model of ballistic impact on a two-dimensional Kevlar KM2® plain-woven fabric has been validated by experiment. This paper shows that it is necessary to experimentally measure material constants of yarns for having good input parameters of the model. Effects of yarn Poisson’s ratio, transverse and shear modulus on impact behaviors of a...
Conference Paper
Full-text available
In order to develop 3D carbon textile structure for civil airplanes application as a turbine blade, we have to predict its geometry and its mechanical properties. NUMTISS project aims to develop a modelling approach of the exact geometry of 3D fabrics taking into account both parameters of the weaving process until those of the resin infusion. Carb...
Conference Paper
This paper presents a multi-scale model that can predict the ballistic impact behaviour of multi-layer plain-woven fabrics using the finite element method. Multi-layer fabrics of 30.5×30.5 cm, woven by high performance yarns Kevlar® 29 3000 denier, are impacted by a 0.3 FSP projectile (Fragment Simulating Projectile). Using a multi-scale approach,...
Conference Paper
In order to develop 3D carbon textile structure into turbine blade for civil airplanes, we have to predict its geometry and its mechanical properties. NUMTISS project aims to develop a model for composite production, from the weaving process until the resin infusion. Carbon fibres are damaged during the weaving process which leads to mechanical str...
Conference Paper
In order to develop carbon reinforced fabric multi-plies into turbine blade for civil airplanes, we have to predict its geometry and its mechanical properties. NUMTISS project aims to develop a model for composite production, from the weaving process until the resin infusion. Carbon fibres are damaged during the weaving process which leads to mecha...
Conference Paper
The paper focuses on the experimental study of impact behaviour of a 3D woven fabric in two cases: perforation and no perforation. A gas guns have been performed for impact tests between 300 and 400 m/s on 3D 4-layers-warp-interlock-woven fabric using a FSP projectile. Fabrics were fixed in the frame with a specific technique using cylinders in ord...
Article
Ce travail porte sur le développement d'une famille d'éléments finis mixtes tridimensionnels, bien adaptés à l'étude des concentrations de contraintes dans les structures en matériaux composites. Dans une première partie, on propose un code précis de calcul de concentrations de contraintes couvrant une large gamme de situations singulières rencontr...
Article
In this paper, damage mechanisms of a 3D interlock woven fabric subjected to ballistic impact were analyzed using a numerical model. Two impact configurations were carried out in order to validate the numerical model with experimental observations: perforation (900m/s) and no-perforation (90m/s). Global deformation of the fabric during impact is de...
Conference Paper
3D interlock woven fabrics are promising material to replace 2D structures in ballistic protection. Structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply mechanic...
Conference Paper
Textile 3D warp interlock structures are a new material applied in ballistic protection [1]. However, the advantages of this material over 2D structures have been confirmed [1, 2, 3, 4, and 5]. We can summarize two main advantages of 3D textile structures in comparison with the 2D ones: (1) Higher resistance to multi-impacts (less damage for an imp...
Article
3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid element...
Conference Paper
A numerical model performed on Radioss, finite element code, was done to study a ballistic impact on a 2D Kevlar KM2 plain-woven fabric. A good agreement between numerical and experiment results show the validation of the numerical model constructed. This paper focused on studying the effect of Poisson’s ratio and transverse modulus of bundle on im...
Article
An optimization procedure using a genetic algorithm has been applied to define the optimum orientation of fibres in a uni-directional laminate in which the fibres were allowed to vary continuously across the domain. The domain was divided into two-dimensional finite elements and anisotropic properties corresponding to a carbon fibre laminate with a...
Conference Paper
If the design of laminates can be considered as globally mastered, the one of junctions still holds unsolved difficulties. In this work, we developed a hybrid finite element to compute accurately the Stress Intensity Factors associated to the singularities around lines at the junction between different anisotropic or/and isotropic materials. After...
Article
An original mixed finite element well suited to stress intensity factor extraction in 3D composite structures is proposed in this study. A numerical example of insert/sandwich junction illustrates the approach.

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Project (1)
Project
To develop and better understand the 3D warp interlock fabric properties to be used as fibrous reinforcement for composite material