Vincent PlacetUniversité de Franche-Comté | UFC · FEMTO-ST Institute Department of Applied Mechanics
Vincent Placet
Dr. Ing.
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Publications (212)
The field of bio-based composites faces challenges in understanding the physical mechanisms providing excellent compromise between stiffness and damping. Potential sources of damping, including the matrix, the fibre, and the interfaces (fibres/fibres and fibres/matrix) are identified in the literature. To better understand damping at the composite...
Previously, we developed a series of processes that involved chemical and enzymatic treatments to extract and separate the fibers from alfa leaves, while also preserving their native mechanical properties, by optimizing the implementation parameters. In this study, we describe the morphology of the alfa leaf, characterize the alfa fibers, and study...
Marginal lands have been proposed to produce non-food crop biomass for energy or green materials. For this purpose, the selection, implementation, and growth optimization of plant species on such lands are key elements to investigate to achieve relevant plant yields. Stinging nettle (Urtica dioica) is a herbaceous perennial that grows spontaneously...
This study describes the production of a new biobased epoxy thermoset and its use with long hemp fibres to produce high-performance composites that are totally biobased. The synthesis of BioIgenox, an epoxy resin derived from a lignin biorefinery, and its curing process have been optimised to decrease their environmental impact. The main objective...
This study investigates the suitability of two thermoplastic polymers that are non-toxic and environmentally friendly, namely polylactic acid (PLA) and recycled maleic anhydride-grafted polypropylene (rMAPP), as potential alternatives to formaldehyde-based adhesives in plywood production. Two types of rotary cut wood veneers, beech and Douglas fir,...
While plant fibers find extensive use across numerous applications, their transverse behavior and mechanical properties lack direct and fiber-scale characterization, posing a significant knowledge gap. This paper investigates, for the first time, the transverse behavior of flax, hemp and nettle fibers through Single Fiber Transverse Compression Tes...
Epoxy resin thermosets (ERTs) are an important class of polymeric materials. However, owing to their highly cross-linked nature, they suffer from poor recyclability, which contributes to an unacceptable level of environmental pollution. There is a clear need for the design of inherently recyclable ERTs that are based on renewable resources. We pres...
In this study, the influence of "bear claw" or indented growth ring anatomical patterns on the vibro-mechanical behavior of spruce wood have been investigated , particularly in the context of utilizing these singu-larities/specific features for the construction of violins. By employing vibrometry and modal analysis followed by finite element model...
In the literature, hemp shives have been proposed as adsorbents capable of effectively complexing metals in aqueous solution. However, studies on the localization of metals in these multicell type lignocellulosic materials are scarce and further description of adsorption sites are required for better optimization of adsorbent capacity. In this arti...
Analytical models of Single Fiber Transverse Compression Tests (SFTCTs) are commonplace for the identification of a fiber’s apparent transverse elastic modulus ET\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength...
This paper aims to present a hemp-based natural fibres composite value chain that could be implemented in biocomposite structures and replace synthetic fibres. Life cycle assessment (LCA) allows the assessment of the environmental footprint of the hemp fibre reinforcement value chain. This general case is complemented with two hemp fibre reinforcem...
In this last decade, numerous works have been published on the use of metal organic frameworks (MOFs) for applications in adsorption field to remove contaminants from aqueous solutions. However, little is known about MOFs as adsorbents for the removal of fluoride ions from real effluents. In this work, a highly porous MOF, UiO-66-NH 2 , was used fo...
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...
Structural Health Monitoring (SHM) and Natural Fibres Composites (NFC) have lived
since early 2000’s important progress due to the needs of reducing material consumption and
weight in operating structures while limiting the environmental footprint and increasing the
safety of such structures. Acoustic Emission (AE) is one of the numerous solutions...
Structural Health Monitoring (SHM) and Natural Fibres Composites (NFC) have livedsince early 2000’s important progress due to the needs of reducing material consumption andweight in operating structures while limiting the environmental footprint and increasing thesafety of such structures. Acoustic Emission (AE) is one of the numerous solutions tha...
This work describes a new class of sandwich panels made of hemp fibre composites and eco-friendly core materials (balsa, paper honeycomb and recycled polyethylene terephthalate foam). The biobased panels are designed to replace analogous glass fibre mat solutions widespread in the automotive sector. Compared to their fossil benchmarks, these panels...
Damping properties of plant fiber composites have been quite widely investigated based on macroscale techniques. Considering their heterogeneous and hierarchical microstructure, it is also necessary to study their damping behavior at the microscale to provide better insight into the dissipation origins and mechanisms. This article proposes a charac...
Various papers in the open source literature have shown that the tensile properties of plant fibres are very scattered. To date, this difference has been viewed as an obstacle to the use of biobased composites in structural applications. However, this question of dispersion has yet not been extensively addressed at the composite scale. Therefore, t...
Sandwich panels are structures employed in many different applications. Here, sandwich panels with the core made of Arundo donax rings and the skins made of flax fibre reinforced epoxy composites are proposed. The influence of the surface roughness of the rings on the mechanical properties is investigated. Pull-off tests between the ring and the sk...
The stinging nettle Urtica dioica L. is a perennial crop with low fertilizer and pesticide requirements, well adapted to a wide range of environmental conditions. It has been successfully grown in most European climatic zones while also promoting local flora and fauna diversity. The cultivation of nettle could help meet the strong increase in deman...
Transverse compression tests are the established way to identify the transverse mechanical properties of single fibers. However, to the authors knowledge, the influence of an angle between the two compression platens has never been studied or quantified. In this paper, the importance of platen parallelism is studied for the first time through: nume...
Hemp-based materials have been recently proposed as adsorbents for metals present in aqueous solutions using adsorption-oriented processes. This study aims to reveal the adsorption mechanism of materials prepared from hemp shives as co-products of the hemp industry, namely sodium carbonate-activated (SHI-C) and polycarboxylic agent-grafted (SHI-BTC...
Monitoring integrity of operating structures has become a crucial need in industrial applications while motivation for more sustainable materials pushes forward the development of natural fibre composites (NFC). The complexity and variability of their failure behaviour and mechanical properties still limit the exploitation of their full potential....
Hemp is a sustainable source of natural fibres that can contribute to meet the increasing demand for technical applications in the textile and the composite sectors. Continuous reinforcements can be produced using the existing flax machinery, initially developed for textile purposes. To achieve competitive and economically viable fibre yields and a...
In this study, a series of hemp shives (chènevotte) with different chemical compositions and properties, namely a raw (SHI-R), a washed with water (SHI-W), three samples chemically modified with KOH (SHI-OH), Na2CO3 (SHI-C) or H3PO4 (SHI-H), and a hemp shives sample prepared by grafting of carboxylic groups (SHI-BTCA), were used as adsorbents for t...
Treatment of wastewater pollution is a critical issue in the context of growing population and industrialization. Actual treatment methods are expensive and not fully effective and rely on fossil fuel-derived chemicals, thus calling for alternative adsorption methods on natural materials such as hemp. Industrial hemp (Cannabis sativa Linn) is a hig...
Despite the increased use of hemp fiber, negligible attention has been given to upgrade the hemp hurd, which constitutes up to 70 wt % of the hemp stalk and is currently considered a low-value byproduct. In this work, valorization of hemp hurd was performed by reductive catalytic fractionation (RCF) in the presence of a metal catalyst. We found an...
The development of sustainable sandwich materials is needed in the transportation sector to address environmental concerns related to the production and operation of vehicles. In addition to biobased composite skins, alternatives to classic synthetic core materials must be found to reduce the ecological footprint of whole sandwich-structured compos...
Increasing the production of high-performance natural fibres that minimise their impact on the environment is a challenge that flax (Linum usitatissinum L.) cannot address alone. In flax traditional production territories, hemp (Cannabis sativa L.) can be a complementary source of high added value fibres if their yield of long line fibres can be ma...
Flax has a long and fascinating history. This plant was domesticated around 8,000 bce1 in the Fertile Crescent area2, first for its seeds and then for its fibres1,3. Although its uses existed long before domestication, residues of flax yarn dated 30,000 years ago have been found in the Caucasus area4. However, Ancient Egypt laid the foundations for...
FINEAU (2021–2024) is a trans-disciplinary research project involving French, Serbian, Italian, Portuguese and Romanian colleagues, a French agricultural cooperative and two surface-treatment industries, intending to propose chènevotte, a co-product of the hemp industry, as an adsorbent for the removal of pollutants from polycontaminated wastewater...
Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Report...
Lignocellulosic fibers extracted from plants are considered an interesting raw material for environmentally friendly products with multiple applications. This work investigated the feasibility of using hemp- and flax-based materials in the form of felts as biosorbents for the removal of metals present in aqueous solutions. Biosorption of Al, Cd, Co...
It is generally alleged that the design choices of acoustic guitar bracing patterns lead to a specific sound of the instrument. However, in the presence of strong uncertainties due to variability of material properties and climatic conditions, the robustness of the soundboard dynamics has yet to be investigated. In this study, three types of bracin...
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...
This paper reviews the damping characteristics of plant fiber composites (PFCs) with particular attention regarding their performance with respect to that of synthetic fiber composites (SFCs). Indeed, PFCs have become increasingly popular in many application fields. Their specific characteristics when compared to those of synthetic fibers, such as...
Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Report...
[This paper was initially published in PHME conference in 2016, selected for further publication in International Journal of Prognostics and Health Management.] This paper describes an Autoregressive Partially-hidden Markov model (ARPHMM) for fault detection and prognostics of equipments based on sensors' data. It is a particular dynamic Bayesian n...
Retting of fibrous plants such as flax is an essential step in the extraction of fibre bundles and their transformation into textiles and reinforcement fabrics for use in garments and composites. Dew-retting is traditionally performed from Northwest France to the Netherlands, as the climate is highly favourable for this process. Hemp is a plant tha...
The use of recycled and renewable components in structural applications supports the development of sustainable lightweight structures. Disposed bottle caps can be used to generate eco-friendly honeycomb cores, especially when combined with other eco-friendly components. A natural fibre-based laminate represents an alternative to synthetic fibres,...
This paper investigates the influence of the stress level and hygrothermal conditions on the creep/recovery behaviour of three high-grade composites made of GreenPoxy and flax and hemp fibres. The results show that the levels of instantaneous, time-delayed and residual strains increase with the applied load and the severity of the environment. The...
Quel est l’état mécanique d’un objet conservé dans les collections patrimoniales ? Cet état mécanique est-il compatible avec la valeur d’usage que les musées d’instruments de musique ont pour mission de conserver ? Afin de garantir des modalités déontologiques de conservation des instruments de musique à cordes, une plateforme numérique d’aide à la...
This work describes the bending and shear mechanical properties of a novel concept of sustainable sandwich panel made from unidirectional prepreg flaxtape skins and bamboo rings as a circular core material. A Design of Experiment (DoE) is used to determine the influence of the bamboo diameter and the type of adhesive bonding between core and skins...
Nowadays, the virtual prototyping method is widely used for industrial applications and can lead to a powerful tool for musical instruments making and conservation. Nevertheless, physics-based models of musical instruments are barely developed for this purpose and the confrontation between model predictions and experiments have been the focus of ve...
This study focuses on the development and mechanical testing of a quasi-unidirectional woven hemp fabric for composite
applications. The fabric is designed to combine the advantages of easy handling, impregnability by resin and fiber
alignment. In this sense, low twisted rovings, low crimping characteristics and a high roving density in the main di...
This work investigates the effects of ageing on autoclaved composites made with unidirectional prepreg epoxy and flax tape in environments with 50% and 100% of relative humidity. A Design of Experiment (DoE) has been used first to determine the effect of the ageing time (0, 2, 4, 6, 8 and 16 days), type of bending (3-point and 4-point bending) and...
The ability of Capacitive Micromachined Ultrasonic Transducer (CMUTs) to design broadband sensors for Structural Health Monitoring (SHM) is studied through both multi-frequency and bandwidth aspects. Elementary cells are composed of circular membranes fabricated using the standard MUMPS Process. The multi-frequency aspect, which involves different...
This work describes the physical and mechanical characterisation of unidirectional [0]12 and crossply [(0/90)3/0 " ]S flax fibre reinforced composites fabricated in autoclave using a prepreg flax tape impregnated with fire retardant epoxy polymer. Tensile, bending and impact properties are evaluated along the longitudinal and transverse fibre direc...
This work explores the use of supercritical carbon dioxide (sc-CO2) conditions as an innovative and environmentally friendly treatment of plant fibres to optimize their performance for integration into composite materials. This study evaluates, in particular, the influence of this treatment on the mechanical, thermal, hygroscopic properties and bio...
Acoustic emission (AE) is a passive monitoring technique used for learning about the behaviour of an engineered system. The streaming obtained by continuously recording AE transient signals is treated by a four steps procedure: 1) The detection of salient AE signals by distinguishing noise against non-noise signals using wavelet denoising, 2) the s...
Substitution of fossil energy sources for bio-based ones will require development of efficient processes that can convert inedible and preferably low-value fractions that currently are not used into high-value products. It is desirable that such processes are developed so that both current logistics and infrastructure can be used. Bark, which is th...
This work assesses the potential of nettle (Urtica dioica L.) fibers produced on contaminated lands for composite applications. The nettles studied in this work grew spontaneously and in a prevalent manner in poplar short rotation coppice planted for the phytomanagement of a land contaminated by traces of metals. Results show that the contaminant c...
The literature focusing on the transverse mechanical properties of single fibers is very sparse compared to those related to longitudinal properties. An original characterization method is proposed herein, relying on a micro mechatronics device to implement a transverse compression test which is monitored using 2D full-field measurements. This is s...
The present work investigates the effects of an environmentally friendly treatment based on supercritical carbon dioxide (scCO2) on the interfacial adhesion of flax fibers with thermoset matrices. In particular, the influence of this green treatment on the mechanical (by single yarn tensile test), thermal (by TGA), and chemical (by FT-IR) propertie...
Epoxy resin plays a key role in composite matrices and DGEBA is the major precursor used. With the aim of favouring the use of bio resources, epoxy resins can be prepared from lignin. In particular, diglycidyl ether of isoeugenol derivatives are good candidates for the replacement of DGEBA. This article presents an effective and eco-friendly way to...
This chapter is dedicated to the dynamical mechanical thermal analysis of shape-memory polymers. Temperature obviously plays a major role in the mechanical properties of these materials; hence, the understanding of the physical phenomena driving the shape-memory effect is of first importance for the design of practical applications in which shape-m...