Rostand MOUTOU Pitti

Rostand MOUTOU Pitti
Université Clermont Auvergne | Univ BPC · Polytech’ Clermont-Ferrand

Associate Professor, HDR

About

230
Publications
23,785
Reads
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812
Citations
Introduction
I am the coordinator of the current project CLIMBOIS (2013-2017) “Effects of climatic and mechanical variations on durability of timbers structures”. This project is financially supported by the National Research Agency (ANR). This work aims to improve the analytical formulation of invariant integrals, commonly used to describe the fracture process in wood material, in order to take into account effects of thermal loading and moisture content variation.
Additional affiliations
September 2018 - September 2022
Polytech Clermont-Ferrand
Position
  • Head of Department
July 2015 - present
Université Clermont Auvergne
Position
  • HDR - Researcher
January 2013 - present
French National Centre for Scientific Research
Position
  • Researcher
Education
September 2009
Université Clermont Auvergne
Field of study
  • Civil Engineering, Mechanics

Publications

Publications (230)
Article
Full-text available
This work presents the experimental study of natural drying and cracking of green wood slices of two tropical species. The tests were carried out on slices of Aucoumea klaineana P. and Pterocarpus soyauxii at uncontrolled temperature and relative humidity. To follow the strains, specifical targets were drawn on the slice in the radial and circular...
Article
The present work deals with the beginning of the Eurocode 5 (EC5) generalization to tropical hardwoods loaded in tropical environment. For three (3) years, creep tests were performed on two types of tropical hardwoods beams, Dacryodes Buettneri (Ozigo) and Baillonella Toxisperma (Moabi) from Gabon. Three (3) environments were selected: (i) the shel...
Conference Paper
Full-text available
This paper presents an experimental investigation on Glued Laminated Timber (GLT) beams made with two tropical woods species, for structural purposes. Two tropical wood species with different density and under-exploited were chosen. These are Dacryodes buettneri (Ozigo) and Pterocarpus osun (Padouk), Ozigo species was taken as a reference species....
Article
This work highlights the effect of temperature on the modulus of elasticity following the orthotropic axis of six species of tropical woods: assamela, bibolo, doussié, iroko, movingui, and sapelli of scientific names Afzelia, Pericopsiselata, Distemonanthus benthamianus, Entandrophragma cylindricum, Miliciaexcelsa, and Lovoatrichilioides, respectiv...
Article
Full-text available
This paper deals with an innovative experimental study performed on glued-laminated timber (GLT) beams, machined and made with three tropical hardwood species. Defect-free beams were obtained by combining alternatively the lamellas taken from the densest to the least dense species, to have TRIO and DUO specimens. Then, static 3-point bending tests...
Article
La durabilité des structures dans le génie civil est confrontée à des problèmes de fissurations sous chargements mécaniques complexes associées souvent à des variations climatiques sévères. L'objectif principal de ce travail est de présenter une nouvelle modélisation mathématique pour les problèmes de fissurations tridimensionnelle sous chargement...
Book
Full-text available
The investigation of wood mechanical response in outdoor conditions, subjected to environmental changes, long-term loadings, and time effects, show a complex behavior of this material. This behavior is characterized by a dimensional change which, in most cases, causes initiations and crack propagation until the total collapse of timber structures....
Conference Paper
Full-text available
This paper investigates cracking in opening mode 1 of tropical multi species Glued Laminated Timbers (GLT). The objective is to assess the influence of strength of glue joints on such assemblies. Specimens are tested in Double Cantilever Bending (DCB), and a crack is initiated on the glue joint to facilitate the delamination under a quasi-static lo...
Conference Paper
Full-text available
RESUME Ce travail présente une étude sur l'intégrité des joints de colle entre deux essences de bois tropicaux différent. Les joints sont collés avec un adhésif au Phénol Résorcinol Formaldéhyde (PRF). Les éprouvettes munies de différents joints de colle ont été prélevées sur des poutres en Bois Lamellés Collé (BLC) combinées. Des essais de cisaill...
Article
Full-text available
An innovative experimental protocol is presented, linking a nondestructive (on computed tomography scanner) and destructive approach (bending test on electrostatic press). This study aimed to evaluate the annual growth ring's impact on the mechanical behavior of wood. The tests were carried out on temperate specimens (Pseudotsuga menziesii and Abie...
Article
Full-text available
Chloride-induced corrosion and load induced concrete cracking affect the serviceability and safety of reinforced concrete (RC) structures. Once these phenomena occur simultaneously, the prediction of RC structures' lifetimes becomes a major challenge. The objective of this paper is to propose a methodology to evaluate the effect of loading and crac...
Article
This paper deals with the experimental study devoted to cyclic compressive loading of three tropical species (Aucoumea Klaineana Pierre (AKP), Milicia Excelsa (ME) and Pterocarpus Soyauxii (PS)) at different moisture content (MC) levels. According to the French requirement, NF EN 408, 90 samples are taken from these three species. The experimental...
Conference Paper
Full-text available
Ce travail présente l'étude de la fissuration de Bois Massif Reconstitués (BMR) TRIO et DUO multi essences d'origine tropicale, l'adhésif utilisé est au phénol. Des essences tropicales disponibles et peu exploitées au Gabon ont été utilisées, il s'agit de Staustia kamernesis (Niové), le Dacryodes buettneri (Ozigo) et le Pterocarpus osun (Padouk). U...
Article
h i g h l i g h t s Investigation of environmental and mechanical impact on notched beam used in building. We propose a methodology for the following of deflection, crack and climatic parameters. A mathematical expression of the Module of Elasticity with the shear effects is proposed. Investigation of Thermo-hydro-mechanical behavior of Pseudotsuga...
Conference Paper
Full-text available
The aim of this study is to show the principal advantages brought by the use of thermally modified wood on the field of construction and to develop mathematical models able to predict the structural long time behaviour of this type of material.
Conference Paper
Full-text available
Under mechanical and environmental changes, the behaviour of wood material is very significant. In this case, the modifications due to these impacts can also compromise the durability of timber structures. The present work consists in investigating the damage of green wood tropical Gabonese (Milicia excelsa - Iroko, Aucoumea klaineana – Okoume, and...
Conference Paper
Full-text available
The wood material and timber structures play an important role in the limitation of greenhouse effects (Pambou Nziengui et al. 2017). But in service, their modification and their durability are affected by the mechanical loadings and the environmental conditions (Angellier et al. 2017). Hence, the damage of two European beam species of Pseudotsuga...
Article
Full-text available
The thermo-visco-hydromechanical properties of Abies alba Mills (white fir of Massif Central) are investigated in this paper. These properties are generally complex to study and model because of various couplings that exist between underlying phenomena. In addition, wood is heterogeneous by species, but these properties are generally studied at the...
Conference Paper
Full-text available
Contexte objectifs Dans leur utilisation en structure, les poutres en bois sont soumises, à des sollicitations mécaniques et environnementales qui ont des effets limitant sur leur durée de vie. En effet, la littérature montre que ce couplage amplifie, dans le temps, le vieillissement du bois (Manfoumbi, 2012 ; Saifouni, 2014) et donc de la structur...
Article
Full-text available
Cracking initiation and propagation are frequently recognized as main causes leading to failure of timber structures. Since the kinematics of both processes is largely influenced by environmental conditions, a comprehensive reliability assessment of notched structures should take into account such environmental factors. The main purpose of this pap...
Conference Paper
Full-text available
L'objectif de ce papier est d'étudier la fissuration des essences tropicales gabonaises telles que le Milicia excelsa (iroko), l'Aucoumea klaineana (okoumé) et le Pterocarpus soyauxii (padouk) par une méthode de mesure sans contact. Le taux de restitution d'énergie critique est calculé avec une éprouvette modifiée Mixed Mode Crack Growth (MMCG). Le...
Conference Paper
Full-text available
The following study, shows on the basis of a series of tests carried out on samples of White fir species of the central massif and okume of Gabon, a database of the different physical and mechanical properties of these species. The tests are carried out indoors at room temperature, on specimens sized according to the French standard [AFN 06]. These...
Conference Paper
Full-text available
The complex mechanical loading and high climatic variations on bio-sourced materials as wood implies having a better understanding of their fracture mechanical behavior. The main goal of this work is to present a new mathematical modeling for three-dimensional crack problems under mixed mode loading. The model is based on a new parameter integral e...
Conference Paper
Full-text available
Civil engineering and mechanical structures are usually submitted to mixed mode loading. As a consequence, a mixed mode crack path process occurs. In three-dimensional crack problem, the study of this problem is very important due to multiple problems that require more understanding of the corner point effect and the local effect due to the torsion...
Conference Paper
Full-text available
Moisture levels are considered as a critical environmental impacting factor for wood and its components, as the moisture content (MC) influences virtually all the physical and mechanical properties. Adsorbed moisture is known to cause significant dimensional changes, as well as changes in mechanical properties such as the modulus of elasticity, str...
Conference Paper
Full-text available
Local approach is based on the definition of the local mechanical field near the crack front. This approach allows us to determine the stress intensity factor and compliances. For plan problem, the description of the stress singularity along the crack front is obtained using the Airy stress function. Most of the literature studies carried out deal...
Conference Paper
Full-text available
The mixed mode crack growth process of three tropical species of the Gabonese forest, namely Iroko (Milicia Excelsa), Okume (Pierre Aucoumea klaineana), and Padouk (Pterocarpus soyauxii) is investigated. Various tests were performed at room temperature for two different thicknesses. A field-measurement technique, namely the grid method, was used in...
Article
The cracking properties in opening mode of three tropicals species from the Gabonese forest, namely Iroko (Milicia Excelsa), Okume (Aucoumea klaineana Pierre), and Padouk (Pterocarpus soyauxii), were investigated in this study. Various tests were performed at room temperature and for two different thicknesses. A full-field measurement technique, na...
Chapter
The present study consists in studying the initiation and propagation of cracks at room temperature of three tropical species: Okume (Aucoumea Klaineana), Iroko (Pterocarpus Soyauxii) and Padouk (Malicia Excelsa). A short review of the literature shows that only few studies dealing with the fracture mechanics properties of this type of wood species...
Chapter
In this paper a numerical approach coupling independent path integrals, such as M-integral, to compute the crack driving forces namely the stress intensity factors, and empirical models, for instance Paris-Erdogan’s law, to assess the cumulative fatigue damage (i.e. crack size) during the crack growth process, is proposed. The M-integral derived fr...
Article
Full-text available
This paper focuses on the theoretical and numerical development of the J-integral concept for three-dimensional problems. A new integral parameter, developed for the real three-dimensional case, computes the combined energy release rate for an arbitrary crack front. A path-independent integral is verified in both the static and crack propagation ca...
Article
Full-text available
The process of mixed-mode crack growth of three tropical species of the Gabonese forest, namely iroko (Milicia Excelsa), okume (Pierre Aucoumea klaineana), and padouk (Pterocarpus soyauxii) is studied in this paper. Different tests were carried out at room temperature for different thicknesses. A full-field measurement technique, namely the grid me...
Article
In this study, crack length evolutions evaluated from both experimental analysis (cluster analysis of acoustic emission activity) and numerical modelling are compared. The highlight of the work presented herein is to show the good ability of acoustic emission technique (AET) combined with statistical tools to monitor the crack tip growth within woo...
Conference Paper
Full-text available
One of the main causes of cracking problem is related to water and thermal effects. The wood structures are particularly concerned. The complex mechanical loading and high climatic variations on wood structures implies having a better understanding of their fracture mechanical behavior (Angellier et al. 2017). However, the water and thermal effects...
Chapter
With the environmental impacts coupled with mechanical loadings, the micro-cracks can propagate and drive the collapse of wood materials or timber-based structures. In this case, the rupture in mixed mode coupling mechanical hydric and thermal loads for orthotropic materials is studied. The analytical formulation of the energy release rate is intro...
Conference Paper
Full-text available
Wood is considered as an orthotropic hydro-mechanical material whose mechanical behavior strongly depends on the moisture content and the temperature. Taking into account humidity and temperature variation, the mechanical behavior assessment becomes more complex due to the coupling effect between the mechanical stress and the hydric state (Thermo-H...
Conference Paper
Full-text available
This paper deals with the numerical development of the J-integral concept for three dimensional problems. A new integral parameter in real three-dimensional case, which computes the energy release rate combining an arbitrary crack front, is developed. The Independence of path integral is verified in quasi-static condition. The generalization of the...
Conference Paper
Full-text available
The main goal of this work is to present a new integral for three dimensional crack problems under mixed mode loading. This work is based on a generalization of the M integral proposed initially by Chen and Shield [1] and developed by Moutou Pitti et al. [2] to visco el-stic crack growth process. The aim of this generalization is to propose a new p...