Sofiane Guessasma

• PhD
• Researcher at French National Institute for Agriculture, Food, and Environment (INRAE)

Flax fibers, while offering numerous benefits, are susceptible to mechanical weakening due to the presence of kink-bands within their structure. The novelty of this study lies in linking mechanical behavior to fiber morphology and defects at multiple scales by utilizing X-ray microtomography to generate detailed 3D images of elementary flax fibers,...

Cellulose-based hydrogels (cellulose nanocrystals – CNC & xyloglucans – XG) are processed to obtain new alternatives to synthetic fibers or resource-consuming ones. A flow-focusing method, is used to align CNC & obtain high performances: an external sheath flow focuses the CNC suspension central flow. To qualify orientations, polarized microscope...

Identifying elastic parameters such as Young’s modulus and Poisson’s ratio is an important step in analysing material properties. They can be obtained by different ways : using extensometer, strain gauge, laser or more complex approach such as Digital Image Correlation (DIC). This last technology is getting more notoriety in recent years. DIC has t...

This study investigated how printing conditions influence the fracture behaviour of 3D-printed acrylonitrile butadiene styrene (ABS) under tensile loading. Dog-bone-shaped ABS specimens were produced using the fusion filament fabrication technique, with varying printing angles. Tensile tests were conducted on pre-notched specimens with consistent p...

The emergence of additive manufacturing is an opportunity to process customized parts to control the release of active substances. The hot melt deposition followed by fast stiffening upon cooling leads to structures that closely match numerical models. But, setting edible and resorbable materials is a challenge and some natural biopolymers may be r...

In this study, digital light processing (DLP) was utilized to generate 3D-printed blends composed of photosensitive acrylate-modified polylactic acid (PLA) resin mixed with varying weight ratios of lignin extracted from softwood, typically ranging from 5 wt% to 30 wt%. The microstructure of these 3D-printed blends was examined through X-ray microto...

This work emphasizes an innovative approach utilizing 3D imaging technology based on synchrotron radiation to assess the microstructure of second-phase iron particles and the porous structure within 3D-printed PLA/magnetic iron composites at different printing angles. The study examines how these observations relate to the material’s ductility when...

Dear Colleagues, The full range of uses for symmetry in material structuring by additive manufacturing (AM) processes has not yet been discovered in terms of its potential in driving the performance of designed parts. According to an optimized selection of AM process parameters for a wide variety of materials, we can expect to see tremendous effec...

This research investigates the microstructure and mechanical behaviour of a polylactic acid (PLA)-iron (PLI) composite designed to enable magnetic actuation. Tensile specimens of PLI are produced through Fused Filament Fabrication, incorporating diverse printing angles ranging from 0° to 90°, thereby facilitating the creation of a variety of layups...

This study aims to relate the microstructural arrangement, in particular the symmetry materialized by filament sequencing in the fused filament fabrication process, to the mechanical behavior of printed polyamide. Dog-bone structures were printed using various printing temperatures ranging from 250 °C to 280 °C, which were combined with part orient...

This study aims at relating the microstructural arrangement, in particular the symmetry materialised by filament sequencing in fused filament fabrication process on mechanical behaviour of printed polyamide. Dogbone structures are printed using various printing temperatures, which are combined with part orientation and raster angle that represent t...

Zein, a biopolymer from corn, was plasticized by glycerol and an Active Pharmaceutical Ingredient-Ionic Liquid (API-IL) for its melt processing at 130 °C. In order to enhance the rheological properties of the formulation for 3D printing, the ratio of glycerol to API-IL was adjusted while maintaining a consistent addition of 20% plasticizer. A 50/50...

This study was aimed at considering the potential of wood-based composites processed using additive manufacturing as insulators in the building sector. A polylactic acid blend with 30% wood particles was used as a feedstock material in fused filament technology. Its thermal and mechanical properties were determined for various processing conditions...

This study aims at better understanding the damage and fracture kinetics in flax fibre elements at both the unitary and bundle scales, using an experimental setup allowing optical observation at high recording rate in the course of tensile loading. Defects and issues from flax unitary fibre extraction are quantitated using polarized light microscop...

This study aims at better understanding the damage and fracture kinetics in flax fibres elements at both the unitary and bundle scales using an experimental setup allowing optical observation at high recording rate in the course of tensile loading. Defects issues from flax unitary fibre extraction are quantitated using polarized light microscopy. T...

The orientation of cellulose microfibrils within plant fibres is one of the main factors influencing their mechanical properties. As plant fibres are more and more used as reinforcement for agro-composites, their mechanical properties have a strong influence on the final composite properties. It is, therefore, of interest to obtain reliable informa...

The microdroplet test is commonly used to determine the apparent interfacial shear strength (IFSS) of fibre-reinforced microcomposites. A deeper analysis of the test outcome can provide meaningful information about the fibre / matrix interface behaviour if a predictive approach is adopted. In this study, this predictive approach was used to investi...

Additive manufacturing is a modern manufacturing technology allowing the material structuring at a fine scale. This structuring affects the performance of printed parts. In this study, the quantification of the material arrangement in 3D printed ceramic on the mechanical performance is tackled. The experimental layout considers two main printing pa...

In this study, we propose to revisit the mechanical anisotropy inferred to printed ABS polymers using fused deposition modelling by combining digital image correlation (DIC), mechanical testing and finite element computation. Tensile specimens are printed using different design orientations and raster angles. Monitoring of deformed samples is perfo...

In this work, we propose to study the mechanical anisotropy inferred in printed acrylonitrile butadiene styrene polymer using fused deposition modelling by combining digital image correlation and mechanical testing. Tensile specimens are printed utilising different design orientations and raster angles. Monitoring of deformed samples is performed a...

Tensile properties of elementary flax fibres were investigated through in situ Synchrotron X-ray diffraction in order to understand the effect of tensile loading, on the internal reorganisation of crystalline cellulose; for the first time, these experiments were conducted for different RH conditions. Synchrotron radiation experiments were considere...

Tuning the infill pattern is one of the key features in additive manufacturing to optimise part weight. In this work, the effect of the infill strategy, including rate and pattern type, is studied on the mechanical performance of polylactic acid (PLA)-carbon composite. In particular, three types of patterns and four filling levels are combined. The...

Pulses extruded foods can be envisaged asall solid foams with voids and walls, the latter being considered as a dense starch/protein composite. Pea flour (PF) and blends of pea starch and pea protein isolate (PPI) with different protein contents (0.5-88% dry basis) were extruded to obtain models of dense starch-protein composites. Their morphology...

This paper describes a novel voxel-based technique to accurately model 3D printed continuous yarns of fibre composites at printed filament scale. To cater for the constraints of continuous filament printing, the design strategy here makes use of a set of variables that fully define the printing path as input in the model. A voxel-based algorithm is...

In this study, digital light processing (DLP) was used to achieve 3D-printed composite materials containing photosensitive resin blended with starch and hemp fibers. The synthesis of 3D-printed composites was performed without heating, according to various material combinations ranging from pure photosensitive resin to a mixture of three phases, in...

The viscous sintering kinetics of thermoplastic polymers is generally studied by monitoring the evolution of the bonding neck between two particles (spherical, or cylindrical) and using a refined Frenkel-Eshelby’s model. Recently, we showed that the entire contour of sintering filaments could be modelled by lemniscates as figure-eight shape curves...

This study addresses the potential of using ceramics-based filaments as a feedstock material in an additive manufacturing process. Tensile specimens of PLA-ceramic (PLC) material are manufactured using a fused deposition modelling process, applying various printing parameters including printing angle and part orientation. Mechanical testing is perf...

The cellulose microfibril realignment of unitary flax fibres with contrasted density of structural defects, which are also known as dislocations and defined as zones of microstructure heterogeneities, was investigated upon tensile testing by means of X-ray diffraction performed on SWING beamline at synchrotron SOLEIL. The in situ continuous tensile...

The external shape and internal lumen of flax fibres are investigated using X-ray microtomography (µ-CT) and finite element (FE) modelling. µ-CT reveals an intricate flax fibre and lumen morphology, with mean porosity contents between 0 and 7.2%. The FE model is based on 3D volumes obtained by X-ray µ-CT and tensile testing in the elastic domain. N...

This study aims at showing the potential of additive manufacturing as a new processing route for designing future insulators in the building sector. Polycarbonate (PC) is studied as a possible candidate for designing these new insulators. This polymer offers several advantages, among them fire resistance and stability of its physical properties at...

Biopolymer composites based on pea starch-protein blends and pea flour are processed using extrusion at various levels of specific mechanical energy (SME). Their morphology was a continuous matrix phase of starch with embedded protein particles, as revealed by Confocal Laser Scanning Microscopy (CLSM). The motivation is to correlate the local Young...

Additive manufacturing has attracted keen interest in the medical field in recent decades, especially for bone regeneration. Many additive manufacturing processes have been used to print medical devices such as implants, prostheses, and surgical guides, and for surgical planning in different medical fields, especially orthopedic, maxillofacial and...

The aim of this work is to explore the manufacturing of insulation structures using fused filament deposition of biosourced materials. The approach considers printing of Polylactic acid (PLA) and PLA-flax (PF) structures using varied infill density and printing temperatures. Differential Scanning Calorimetry and Thermal Gravimetry analysis are perf...

In this study, we show the extent of interfacial behaviour in the mechanical performance of thermoplastic polyurethane elastomer (TPU)/acrylonitrile butadiene styrene (ABS) composite material manufactured using droplet-based additive manufacturing. Both the interface orientation and the interface strength are varied during the processing. Prior to...

The use of natural fiber-reinforced polymer composites has been the subject of many research projects, for the development of environment-friendly materials, in recent years. Hence, this paper focuses on the identification of the parameters of mechanical behavior for a PA6/flax fiber composite. Therefore, experimental setups composed of static tens...

Few studies have reported the performance of Polylactic acid (PLA) flax feedstock composite for additive manufacturing. In this work, we report a set of experiments conducted by fused filament technology on PLA and PLA-flax with the aim of drawing a clear picture of the potential of PLA-flax as a feedstock material. Nozzle and bed temperatures are...

Prompted by environmental legislation and citizens’ awareness induced by global warming effects, the market for plant-fibre reinforced composites has been growing steadily for the past 10-20 years, as observed by the substantial increase in academic and industrial research developments. However, the transition to larger production still requires se...

Plant fibres and especially flax can be distinguished from most synthetic fibres by their intricate shape and intrinsic porosity called lumen, which is usually assumed to be tubular. However, the real shape appears more complex and thus might induce stress concentrations influencing the fibre performance. This study proposes a novel representation...

Fibres from annual plants are a sustainable alternative to glass fibres in composite manufacturing. However, both synthetic fibres, such as carbon fibres, and cellulosic fibres exhibit heterogeneities along their lengths, which appear as localised morphological misorientations known as kink-bands. In plant fibres, kink-bands occur due to growing co...

Advances in the additive manufacturing (AM) processes have opened up the possibilities of widely using them in various structural sectors. Since 1980s this technology has been in permanent mutations. The ramification of the AM technology makes it difficult to obtain a clear impression of its potentialities. Predicting and controlling the mechanical...

The aim of this study is to investigate on the compression performance of cellular Polylactic Acid (PLA) manufacturing while using Fused Deposition Modelling. Computer Aided Design (CAD) models of cellular structures are designed using the sequential addition of spherical voids with porosity content varying from 10% to 60%. The three-dimensional (3...

The present investigation aims at the thermal conditions for the printability of nylon using fused deposition modeling (FDM). Dog‐bone like specimens are manufactured under two printing temperatures to measure the tensile performance of 3D printed nylon with respect to the feedstock material properties. Both Scanning Electron Microscopy (SEM) and X...

Résumé L’objectif de ce travail était de comprendre les mécanismes de déstructuration et de formation du bol alimentaire chez le sujet âgé, pour deux aliments céréaliers (brioche et génoise) enrichis en protéines de légumineuses (pois et fève), afin de développer des aliments adaptés au sujet âgé. La déstructuration orale (FOP) de ces aliments a ét...

The influence of the microstructural arrangement of 3D-printed polylactic acid (PLA) on its mechanical properties is studied using both numerical and experimental approaches. Thermal cycling during the laying down of PLA filament is investigated through infra-red measurements for different printing conditions. The microstructure induced by 3D print...

The mechanical properties of sponge cake (SC) and brioche (B), and their pulse protein fortified version (FSC and FB) have been characterized under compression (>90% in height reduction); during recording the evolution of their cellular structure was recorded using high resolution X-ray tomography. Due to protein reinforcement, FB had smaller gas c...

This study reports the combined effect of fly ashes, hemp fibres and shives on strength performance of modified mortars. Fly ashes are firstly processed using a high intensity mechanical milling. Natural fibres are observed using X-ray micro-tomography to reveal the microstructural arrangement. Preliminary formulations are attempted with different...

The mechanical property of 3D-printed components often exhibits anisotropic behaviors and a strong dependence on printing orientations and process parameters. In this study, computational models based on microstructures of 3D-printed ABS polymers are developed using micromechanics of a representative volume element (RVE) to investigate the orthotro...

Besides experimental approaches, the development of new products by extrusion requires the support of theoretical approaches that provide information on process conditions and their effects on product characteristics. Instead of tedious trial and error procedures, process modeling may rapidly help to avoid inappropriate solutions and to focus on es...

The microstructure and mechanical performance of wood-based filament is investigated in the case of Fused Deposition Modelling (FDM) technique using experimental and numerical approaches. The printing process of wood-PLA/PHA is conducted by varying the printing temperature, typically from 210 °C to 250 °C. The filament temperature during the laying...

The use of models and simulators in food industry remains limited, despite its interest to predict complex situations, as shown by an abundant scientific literature . Although carried out in many establishments and universities, teaching about food modelling faces theoretical hurdles (mathematical formalism ...) who tend to discourage students, who...

Cereal foods may be considered as soft solid foams and the study of their damage mechanisms under mechanical load is essential to better capture their texture and to enlighten the process of human mastication1. This work focuses on two cereal foods, sponge-cake (SC) and brioche (B), with a porosity of about 75%. Their mechanical properties have bee...

Purpose This paper aims to investigate the effect of printing temperature on the thermal and the mechanical behaviour of polylactic acid (PLA)-polyhydroxyalkanoate (PHA) blend printed using fused deposition modelling (FDM). Design/methodology/Approach Because of the use of an infra-red camera, thermal cycling during the laying down is quantified....

Polyethylene terephthalate glycol (PETG) is a thermoplastic formed by polyethylene terephthalate (PET) and ethylene glycol and known for his high impact resistance and ductility. The printability of PETG for fused deposition modelling (FDM) is studied by monitoring the filament temperature using an infra-red camera. The microstructural arrangement...

This study aims at reporting a strategy of designing cellular materials based on Voronoi–Monte Carlo approach for additive manufacturing. The approach is implemented to produce a fully connected cellular structure in the design space without producing material discontinuity. The main characteristics of the cellular structure, such as the density an...

The effect of the substitution by 5%, 15%, 30% and 45% of cement in mortars by milled kaolinite has been studied. Milled Kaolinite clay is obtained by using planetary ball mill. The influence on the mechanical performance and on the pozzolanic reactions are discussed. For both CEM I and CEM II formulations, after only 7 days of curing, the compress...

This study aims at revealing the role of microstructural arrangement on the mechanical behaviour of printed PLA-Hemp using Fused Deposition Modelling (FDM). 3D printing is performed by varying the printing temperature. The laying down process is monitored using infra-red measurement. X-ray micro-tomography is used to acquire the 3D microstructure o...

Fused deposition modeling (FDM) is one of the most popular additive manufacturing techniques for polymers. Despite the numerous works on the printability of various types of polymers, there is a lack in understanding the role of the microstructure on the mechanical performance of printed parts. This work aims at addressing this particular point for...

This study combines experimental testing and computation analysis to reveal the role of defects and sub-micrometric microstructure in tensile behavior of hemp bast fibers. In particular, these structural defects represent the footprint of the processes to which the fibers elements are subject along the whole transformation chain from the plant to t...

Cereal foods can be considered as cellular solids: texture is defined by their structure and mechanical properties. Elderly people show a significant alteration of oral health and salivation, causing difficulties to eat. Therefore, there is a need to understand chewing mechanisms of soft cereal foods in order to develop better food products that ar...

The main purpose of this study is to highlight the thermal and mechanical characterization of printed copolyester-based polymer. The variety of benefits of this material, such as its food contact compliance and important mechanical properties, have proved to be effective in huge field of applications, including medical sector and packaging uses. Ho...

This work tackles crack propagation mechanisms of styrene butadiene and natural rubbers, both subject to cyclic loading under a positive load ratio. The experimental evidence is based on pure shear loading of notched specimens supported by SEM analysis of fracture surfaces. Relationship between crack growth rate and tearing energy is revisited. The...

Purpose Assembling items to achieve bigger parts seems to be the solution to counterbalance the dimension limits of 3D printing. This work aims to propose an approach to achieve optimal assembling. Design/methodology/approach Acrylonitrile butadiene styrene polymer samples were printed using fused deposition modelling (FDM). These samples were a...

The aim of this study is to investigate the printability conditions of a copolyester based polymer that has not received yet much attention. This material presents several advantages over PLA and ABS including its food contact compliance and BPA (Bisphenol A) free formulation. The determination of optimal conditions to print copolyester with FDM pr...

Cereal foods can be considered as cellular solids: texture is defined by their structure and mechanical properties[1] Elderly people show alteration of oral health[2] and salivation[3], causing difficulties to eat There is a need to understand chewing and FOP mechanisms of soft cereal foods in order to develop better food products for the elderly A...

The current applications of 3D printing by Material Extrusion (ME) to biopolymers other than polylactic acid (PLA) are scarce. The present paper reflects on the benefits and challenges of using plant biopolymers in for ME. The challenges are considered on the basis of (1) a review of additive manufacturing (AM) techniques applicable to biopolymers,...

Introduction: Starch-based materials were designed using a special extrusion die in order to obtain a tube-shaped device for application to salivary duct treatment in the field of endoscopy, i.e., sialendoscopy . Methods: Extrusion process was used to produce starch tubes. Mechanical properties of the dry tube before implantation were determined us...

Supplementary file 1 contains Table S1 and Figure S1.

This study aims at implementing an interfacial model to capture the role of interfaces in polyester-based composites reinforced by metallic fibres. A pull-out test of single aluminium and steel fibres embedded in unsaturated polyester matrix is performed. Finite element computation is performed to simulate the typical response of the pull-out test...

A novel experimental setup is presented to reveal damage mechanisms in bast fibers. 3D imaging at submicronic scale based on X-ray micro-tomography is combined with in-situ tensile experiments of both elementary fibers and bundles. The results reveal that the relevant scale that drives failure of hemp lignocellulosic fibers is submicronic. In-situ...

The aim of this work is to deliver a precise statement about the mechanical effect of microstructural defects induced by stereolithography. Design of cellular structures based on a photosensitive resin with varied porosity content is performed up to 60%. The compressive behaviour of these structures is captured and microstructural defects are analy...

The main purpose of this research work is to investigate the mechanical performance of hemp modified mortars. This study focuses on which formulation would entail the best compressive and flexural strengths, as well as the optimal adhesion of fibres and shives with the cementitious matrix. After deciding about the optimal formulation involving mixt...

Technological innovations in the food sector have been driven by high-volume production lines over the past decades. Cost-efficiency of processing and price competitiveness of final products have been major factors. The economics of up-scaling have led to new technologies that are more efficient in terms of throughput and utilization of (homogenous...

In this work, we experimentally evaluate the rendering of topology optimisation through the design of hollow structures manufactured using a 3D printing technique. The moving asymptote method is used as a mathematical optimisation strategy to virtually minimise the volume of 2D designs subject to hydrostatic pressure by half. Designs are converted...

To reveal the potential and limits of multi-material three-dimensional (3D) printed parts in droplet-based additive manufacturing, a study combining tensile experiments and 3D imaging technique is proposed. A polymeric composite structure made of acrylonitrile butadiene styrene and thermoplastic polyurethane is manufactured using a two extrusion he...