SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 14 Oct 2024 17:15:40 GMT2024-10-14T17:15:40ZA self-affine geometrical model of dynamic RT-PMMA fractures: implications for fracture energy measurements
http://hdl.handle.net/10985/9600
A self-affine geometrical model of dynamic RT-PMMA fractures: implications for fracture energy measurements
SCHMITTBUHL, Jean; NOEL, Olivier; FOND, Christophe; KOPP, Jean-Benoit
Profilometric imaging of fracture surfaces of rubber toughened polymer has been performed at two different resolutions (a) at large scales [10 μ\upmu m–25 mm] using an opto-mechanical profilometer and (b) at small scales [0.195 μ\upmu m–0.48 mm] using an interferometric optical microscope. We introduced a self-affine geometrical model using two parameters: the Hurst exponent and the topothesy. We showed that for rubber toughened materials the approximation of the created surface by a mean flat plane leads to a poor estimation of the dynamic fracture energy GIdcG_{Idc}. The description of the created rough fracture surface by a self-affine model is shown to provide a significantly better approximation. A new and original geometrical method is introduced to estimate self-affine parameters: the 3D surface scaling method. Hurst exponents are shown to be unique, χ=0.6±0.1\chi =0.6\pm 0.1 for the different fracture zones and measurement scales. Topothesy ratios indicate a significant difference of fracture surface roughness amplitude depending on the observation resolution when the detrending technique is not correctly introduced.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/96002015-01-01T00:00:00ZSCHMITTBUHL, JeanNOEL, OlivierFOND, ChristopheKOPP, Jean-BenoitProfilometric imaging of fracture surfaces of rubber toughened polymer has been performed at two different resolutions (a) at large scales [10 μ\upmu m–25 mm] using an opto-mechanical profilometer and (b) at small scales [0.195 μ\upmu m–0.48 mm] using an interferometric optical microscope. We introduced a self-affine geometrical model using two parameters: the Hurst exponent and the topothesy. We showed that for rubber toughened materials the approximation of the created surface by a mean flat plane leads to a poor estimation of the dynamic fracture energy GIdcG_{Idc}. The description of the created rough fracture surface by a self-affine model is shown to provide a significantly better approximation. A new and original geometrical method is introduced to estimate self-affine parameters: the 3D surface scaling method. Hurst exponents are shown to be unique, χ=0.6±0.1\chi =0.6\pm 0.1 for the different fracture zones and measurement scales. Topothesy ratios indicate a significant difference of fracture surface roughness amplitude depending on the observation resolution when the detrending technique is not correctly introduced.Experimental Investigation and Discrete Element Modelling of Composite Hollow Spheres Subjected to Dynamic Fracture
http://hdl.handle.net/10985/17021
Experimental Investigation and Discrete Element Modelling of Composite Hollow Spheres Subjected to Dynamic Fracture
CORE, Arthur; CHARLES, Jean-Luc; VIOT, Philippe; DAU, Frédéric; KOPP, Jean-Benoit
This paper deals with the characterization and the numerical modelling of the collapse of composite hollow spherical structures developed to absorb energy during high velocity impacts. The structure is composed of hollow spheres (ϕ=2–30 mm) made of epoxy resin and mineral powder. First of all, quasi-static and dynamic (v=5 mm·min−1 to v=2 m·s−1) compression tests are conducted at room temperature on a single sphere to study energy dissipation mechanisms. Fracture of the material appears to be predominant. A numerical model based on the discrete element method is investigated to simulate the single sphere crushing. The stress-strain-time relationship of the material based on the Ree-Eyring law is numerically implemented. The DEM modelling takes naturally into account the dynamic fracture and the crack path computed is close to the one observed experimentally in uniaxial compression. Eventually, high velocity impacts (v>100 m·s−1) of a hollow sphere on a rigid surface are conducted with an air cannon. The numerical results are in good agreement with the experimental data and demonstrate the ability of the present model to correctly describe the mechanical behavior of brittle materials at high strain rate.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/170212017-01-01T00:00:00ZCORE, ArthurCHARLES, Jean-LucVIOT, PhilippeDAU, FrédéricKOPP, Jean-BenoitThis paper deals with the characterization and the numerical modelling of the collapse of composite hollow spherical structures developed to absorb energy during high velocity impacts. The structure is composed of hollow spheres (ϕ=2–30 mm) made of epoxy resin and mineral powder. First of all, quasi-static and dynamic (v=5 mm·min−1 to v=2 m·s−1) compression tests are conducted at room temperature on a single sphere to study energy dissipation mechanisms. Fracture of the material appears to be predominant. A numerical model based on the discrete element method is investigated to simulate the single sphere crushing. The stress-strain-time relationship of the material based on the Ree-Eyring law is numerically implemented. The DEM modelling takes naturally into account the dynamic fracture and the crack path computed is close to the one observed experimentally in uniaxial compression. Eventually, high velocity impacts (v>100 m·s−1) of a hollow sphere on a rigid surface are conducted with an air cannon. The numerical results are in good agreement with the experimental data and demonstrate the ability of the present model to correctly describe the mechanical behavior of brittle materials at high strain rate.Strain rate effect on the mechanical properties of a glass fibre reinforced acrylic matrix laminate. An experimental approach
http://hdl.handle.net/10985/17357
Strain rate effect on the mechanical properties of a glass fibre reinforced acrylic matrix laminate. An experimental approach
CADIEU, Lucien; JUMEL, Julien; BEGA, Jéremy; FROUSTEY, Catherine; KOPP, Jean-Benoit
The aim of this study is to evaluate the effect of the loading rate on the mechanical properties and damage mechanisms of a Glass/Elium150 laminate composite. Quasi-static indentation (QS) and low energy dynamic impact (DYN) tests which simulate lifetime structural loadings (dropped tool, gravel impacts, …) are lead. A specific experimental approach is developed to compare results of both experiments. The effect of the loading rate on the structural response (stiffness, dissipated energy) of the composite is highlighted. The numerous damage mechanisms involved in the collapse of the material are observed at a microscopic scale using both optical and scanning electron microscopy (SEM). Finally an intra-laminar crack propagation mechanism is described based on post-mortem observations at ply scale to explain the formation of interlaminar cracks
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/173572019-01-01T00:00:00ZCADIEU, LucienJUMEL, JulienBEGA, JéremyFROUSTEY, CatherineKOPP, Jean-BenoitThe aim of this study is to evaluate the effect of the loading rate on the mechanical properties and damage mechanisms of a Glass/Elium150 laminate composite. Quasi-static indentation (QS) and low energy dynamic impact (DYN) tests which simulate lifetime structural loadings (dropped tool, gravel impacts, …) are lead. A specific experimental approach is developed to compare results of both experiments. The effect of the loading rate on the structural response (stiffness, dissipated energy) of the composite is highlighted. The numerous damage mechanisms involved in the collapse of the material are observed at a microscopic scale using both optical and scanning electron microscopy (SEM). Finally an intra-laminar crack propagation mechanism is described based on post-mortem observations at ply scale to explain the formation of interlaminar cracksDynamic fracture in a semicrystalline biobased polymer: an analysis of the fracture surface
http://hdl.handle.net/10985/19855
Dynamic fracture in a semicrystalline biobased polymer: an analysis of the fracture surface
KOPP, Jean-Benoit; GIRARDOT, Jeremie
The fracture behaviour of a semi-crystalline bio-based polymer was studied. Dynamic fracture tests on strip band specimens were carried out. Fracture surfaces were observed at different scales by optical and electron microscopy to describe cracking scenarios. Crack initiation, propagation and arrest zones were described. Three distinct zones are highlighted in the initiation and propagation zone: a zone with conical markings, a mist zone and a hackle zone. The conical mark zone shows a variation in the size and density of the conical marks along the propagation path. This is synonymous with local speed variation. Microcracks at the origin of the conical marks in the initiation zone seem to develop from the nucleus of the spherulites. In the propagation zone with complex roughness, the direction of the microcracks and their cracking planes are highly variable. Their propagation directions are disturbed by the heterogeneities of the material. They branch or bifurcate at the level of the spherulites. In the arrest zone, the microcracks developed upstream continue to propagate in different directions. The surface created is increasingly smoother as the energy release rate decreases. It is shown that the local velocity of the crack varies in contrast to the macroscopic speed. A specific setup allowing to estimate the minimum fracture energy of the material in order to maintain the rapid propagation of the crack is proposed for materials with antagonistic behaviour: ductile at initiation and brittle in propagation.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/198552020-01-01T00:00:00ZKOPP, Jean-BenoitGIRARDOT, JeremieThe fracture behaviour of a semi-crystalline bio-based polymer was studied. Dynamic fracture tests on strip band specimens were carried out. Fracture surfaces were observed at different scales by optical and electron microscopy to describe cracking scenarios. Crack initiation, propagation and arrest zones were described. Three distinct zones are highlighted in the initiation and propagation zone: a zone with conical markings, a mist zone and a hackle zone. The conical mark zone shows a variation in the size and density of the conical marks along the propagation path. This is synonymous with local speed variation. Microcracks at the origin of the conical marks in the initiation zone seem to develop from the nucleus of the spherulites. In the propagation zone with complex roughness, the direction of the microcracks and their cracking planes are highly variable. Their propagation directions are disturbed by the heterogeneities of the material. They branch or bifurcate at the level of the spherulites. In the arrest zone, the microcracks developed upstream continue to propagate in different directions. The surface created is increasingly smoother as the energy release rate decreases. It is shown that the local velocity of the crack varies in contrast to the macroscopic speed. A specific setup allowing to estimate the minimum fracture energy of the material in order to maintain the rapid propagation of the crack is proposed for materials with antagonistic behaviour: ductile at initiation and brittle in propagation.Rapid crack propagation in PA11: An application to pipe structure
http://hdl.handle.net/10985/17335
Rapid crack propagation in PA11: An application to pipe structure
FOND, Christophe; HOCHSTETTER, Gilles; KOPP, Jean-Benoit
Dynamic fracture mechanism in Polyamide 11 (PA11) material has been described at laboratory scale to access to an intrinsic material parameter. A liquid transportation application is considered with polymer pipes. A preliminary numerical analysis of the rapid crack propagation (RCP) in polymer pipe is firstly realised. Two boundary conditions, imposed displacement or pressure, are numerically investigated. The work of external forces is not negligible for pressurized polymer pipe. A reliable estimate of the dynamic energy release rate GId is in this last case not guaranteed. To limit unwanted structural effects a specific experimental device has been used to ensure a permanent regime of RCP in Pre-Stressed Pipe Specimen (PS2). Experimental dynamic fracture tests are realised with Polyamide 11 PS2. Dynamic instabilities inducing “ring-off” and “snake” mechanisms which could appear during full-scale test are not observed with this new test. A finite element procedure is used to estimate the material toughness GID of PA11. Knowing the crack tip location during RCP inertia effects (i.e. kinetic energy) are quantified. The mean crack tip velocity is observed not to change in PA11 whatever the crack configuration (branching or not). This velocity is known to be the crack branching velocity (≈0.6cR). The average dynamic energy release rate 〈GID〉 is equal to 1.5± 0.1 kJm−2 at the crack branching velocity. The nontrivial fracture surface roughness is observed with a scanning electron microscope.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/173352018-01-01T00:00:00ZFOND, ChristopheHOCHSTETTER, GillesKOPP, Jean-BenoitDynamic fracture mechanism in Polyamide 11 (PA11) material has been described at laboratory scale to access to an intrinsic material parameter. A liquid transportation application is considered with polymer pipes. A preliminary numerical analysis of the rapid crack propagation (RCP) in polymer pipe is firstly realised. Two boundary conditions, imposed displacement or pressure, are numerically investigated. The work of external forces is not negligible for pressurized polymer pipe. A reliable estimate of the dynamic energy release rate GId is in this last case not guaranteed. To limit unwanted structural effects a specific experimental device has been used to ensure a permanent regime of RCP in Pre-Stressed Pipe Specimen (PS2). Experimental dynamic fracture tests are realised with Polyamide 11 PS2. Dynamic instabilities inducing “ring-off” and “snake” mechanisms which could appear during full-scale test are not observed with this new test. A finite element procedure is used to estimate the material toughness GID of PA11. Knowing the crack tip location during RCP inertia effects (i.e. kinetic energy) are quantified. The mean crack tip velocity is observed not to change in PA11 whatever the crack configuration (branching or not). This velocity is known to be the crack branching velocity (≈0.6cR). The average dynamic energy release rate 〈GID〉 is equal to 1.5± 0.1 kJm−2 at the crack branching velocity. The nontrivial fracture surface roughness is observed with a scanning electron microscope.Dynamic Fracture of a Semi-Crystalline Bio-Based Polymer Pipe: Effect of Temperature
http://hdl.handle.net/10985/21417
Dynamic Fracture of a Semi-Crystalline Bio-Based Polymer Pipe: Effect of Temperature
KOPP, Jean-Benoit; GIRARDOT, Jeremie
The influence of temperature on the resistance to rapid crack propagation of a semi-crystalline bio-based polymer was studied. The experimental results described in this study allow to initiate a first discussion on the role of viscos-ity and its link with the fracture behaviour and a heterogeneous microstruc-ture such as the semi-crysalline polymer. Dynamic fracture tests on pipes were carried out. It would appear that a temperature decrease of approx-imately 40 ̊C relative to ambient has no significant influence on the average crack propagation velocity (≈0.6cR), fracture energy and surface roughness. On the contrary, crack propagation paths seem to vary with temperature. The difference in fracture behaviour between the amorphous and crystalline phase varies significantly as a function of temperature. The difference between the initiation resistance and the rapid propagation also varies. This difference seems to be significantly reduced by lowering the temperature. The mechan-isms of cavitation damage and plastic flow are increasingly limited by the de-crease in temperature (and therefore in macromolecular mobility). Crack propagation in the pipe is more extensive and therefore more critical. This is emphasised in particular by the probability of the material to be macro-branched as the temperature decreases.
Fri, 01 Jan 2021 00:00:00 GMThttp://hdl.handle.net/10985/214172021-01-01T00:00:00ZKOPP, Jean-BenoitGIRARDOT, JeremieThe influence of temperature on the resistance to rapid crack propagation of a semi-crystalline bio-based polymer was studied. The experimental results described in this study allow to initiate a first discussion on the role of viscos-ity and its link with the fracture behaviour and a heterogeneous microstruc-ture such as the semi-crysalline polymer. Dynamic fracture tests on pipes were carried out. It would appear that a temperature decrease of approx-imately 40 ̊C relative to ambient has no significant influence on the average crack propagation velocity (≈0.6cR), fracture energy and surface roughness. On the contrary, crack propagation paths seem to vary with temperature. The difference in fracture behaviour between the amorphous and crystalline phase varies significantly as a function of temperature. The difference between the initiation resistance and the rapid propagation also varies. This difference seems to be significantly reduced by lowering the temperature. The mechan-isms of cavitation damage and plastic flow are increasingly limited by the de-crease in temperature (and therefore in macromolecular mobility). Crack propagation in the pipe is more extensive and therefore more critical. This is emphasised in particular by the probability of the material to be macro-branched as the temperature decreases.A thick cellular structural adhesive: Identification of its behavior under shear loading
http://hdl.handle.net/10985/24586
A thick cellular structural adhesive: Identification of its behavior under shear loading
WETTA, Maxime; KOPP, Jean-Benoit; LE BARBENCHON, Louise; VIOT, Philippe
This study focuses on the link between the microstructure and the mechanical behavior under shear loading of a thick cellular structural adhesive (TCSA). X-ray microtomography and image post-processing were first used to perform 3D-quantitative microstructure analysis. The cells morphometric parameters and their orientations were studied. The foaming process boundary conditions seems to create local density gradients changing the cells dimensions and shape. The cells are more spherical in the core of the material whereas being more ellipsoidal close to the upper and lower faces of the samples creating a skin layer. The effect on the strain field of this skin layer has then been highlighted. Secondly, a shear test method using an Arcan setup coupled with digital image correlation was used and allowed to observe the mechanical behavior of the material under shear loadings. Instead of the material being cellular and heterogenous, it has been found that the strain field can be considered homogeneous at macroscopic scale to extract the properties on a homogeneous equivalent material. Shear test on samples with different densities were performed. Using the relation developed by Gibson and Ashby linking the shear modulus to the density squared is a first approximation, at this scale, to predict and describe the mechanical behavior under shear loading.
Thu, 01 Jun 2023 00:00:00 GMThttp://hdl.handle.net/10985/245862023-06-01T00:00:00ZWETTA, MaximeKOPP, Jean-BenoitLE BARBENCHON, LouiseVIOT, PhilippeThis study focuses on the link between the microstructure and the mechanical behavior under shear loading of a thick cellular structural adhesive (TCSA). X-ray microtomography and image post-processing were first used to perform 3D-quantitative microstructure analysis. The cells morphometric parameters and their orientations were studied. The foaming process boundary conditions seems to create local density gradients changing the cells dimensions and shape. The cells are more spherical in the core of the material whereas being more ellipsoidal close to the upper and lower faces of the samples creating a skin layer. The effect on the strain field of this skin layer has then been highlighted. Secondly, a shear test method using an Arcan setup coupled with digital image correlation was used and allowed to observe the mechanical behavior of the material under shear loadings. Instead of the material being cellular and heterogenous, it has been found that the strain field can be considered homogeneous at macroscopic scale to extract the properties on a homogeneous equivalent material. Shear test on samples with different densities were performed. Using the relation developed by Gibson and Ashby linking the shear modulus to the density squared is a first approximation, at this scale, to predict and describe the mechanical behavior under shear loading.A damaging beam-lattice model for quasi-brittle fracture
http://hdl.handle.net/10985/21460
A damaging beam-lattice model for quasi-brittle fracture
SAGE, Margaux; GIRARDOT, Jeremie; KOPP, Jean-Benoit; MOREL, Stéphane
This work aims to propose a new damaging beam-lattice model using the Discrete Element Method paradigm dedicated to the simulation of quasi-brittle fracture under complex loadings. Enrichment of the elastic Euler–Bernoulli beam link, inspired by the cohesive zone models, is proposed to provide a damageable behavior in mixed mode and contribution of frictional behavior is not considered in this first version of the damage model. The tensile contribution on the beam link is taken into account from the first order elongation of the beam while all other contributions, i.e. bending, shear, and torsion are considered from the second-order elongation of the beam. These orders of elongation refer to beam theory, where the first elongation is induced by a force normal to the cross-section and the second is the elongation of the curvilinear length of the beam resulting from shear, bending and torsion loads. As these two kinematics do not correspond to the conventional modes I, II, and III, a deep checking step of the model is undertaken. First, mixed-mode testing on a single beam is performed to monitor the energy components dissipated in each mode and to ensure that energy dissipated in mixed mode exhibits a monotonic evolution between boundary values related to pure modes. Based on this first verification, a tensile test and a compression one are simulated on a cylinder specimen to evaluate the model capabilities to qualitatively describe the well-known characteristics of quasi-brittle fracture such as failure facies, unilateral effect, and the ratio between the compression and tensile strength. Finally, the model is used to simulate a complex crack propagation test coming from the recent international Carpiuc benchmark.
Sat, 01 Jan 2022 00:00:00 GMThttp://hdl.handle.net/10985/214602022-01-01T00:00:00ZSAGE, MargauxGIRARDOT, JeremieKOPP, Jean-BenoitMOREL, StéphaneThis work aims to propose a new damaging beam-lattice model using the Discrete Element Method paradigm dedicated to the simulation of quasi-brittle fracture under complex loadings. Enrichment of the elastic Euler–Bernoulli beam link, inspired by the cohesive zone models, is proposed to provide a damageable behavior in mixed mode and contribution of frictional behavior is not considered in this first version of the damage model. The tensile contribution on the beam link is taken into account from the first order elongation of the beam while all other contributions, i.e. bending, shear, and torsion are considered from the second-order elongation of the beam. These orders of elongation refer to beam theory, where the first elongation is induced by a force normal to the cross-section and the second is the elongation of the curvilinear length of the beam resulting from shear, bending and torsion loads. As these two kinematics do not correspond to the conventional modes I, II, and III, a deep checking step of the model is undertaken. First, mixed-mode testing on a single beam is performed to monitor the energy components dissipated in each mode and to ensure that energy dissipated in mixed mode exhibits a monotonic evolution between boundary values related to pure modes. Based on this first verification, a tensile test and a compression one are simulated on a cylinder specimen to evaluate the model capabilities to qualitatively describe the well-known characteristics of quasi-brittle fracture such as failure facies, unilateral effect, and the ratio between the compression and tensile strength. Finally, the model is used to simulate a complex crack propagation test coming from the recent international Carpiuc benchmark.Influence of the microstructure on the compressive behaviour of porous aluminas: From microstructural characterisation to fracture mechanisms
http://hdl.handle.net/10985/24883
Influence of the microstructure on the compressive behaviour of porous aluminas: From microstructural characterisation to fracture mechanisms
HENRY, Quentin; VIOT, Philippe; LE BARBENCHON, Louise; COSCULLUELA, Antonio; KOPP, Jean-Benoit
The mechanical response of porous aluminas under compressive loading was studied and compared with the fracture mechanisms. Aluminas with a wide range of pore sizes and porosity rates (1–60%) were produced to deconvolve the effects of pore rate, size and morphology on mechanical response. A transition from brittle to quasi-brittle behaviour appears when the porosity rate reaches 60% and a decrease in mechanical properties as the porosity rate increased. At a porosity rate of 20%, a first alumina was produced with micrometric, interconnected pores, while a second was produced with isolated spherical and mesometric pores. The Young’s modulus is little affected by pore size and morphology, while failure stress decreases with increasing pore size. At iso-density, different grain arrangements lead to different fracture mechanisms despite a similar mechanical response: the more compact the grain arrangement, the more transgranular the crack propagation.
Sat, 01 Jun 2024 00:00:00 GMThttp://hdl.handle.net/10985/248832024-06-01T00:00:00ZHENRY, QuentinVIOT, PhilippeLE BARBENCHON, LouiseCOSCULLUELA, AntonioKOPP, Jean-BenoitThe mechanical response of porous aluminas under compressive loading was studied and compared with the fracture mechanisms. Aluminas with a wide range of pore sizes and porosity rates (1–60%) were produced to deconvolve the effects of pore rate, size and morphology on mechanical response. A transition from brittle to quasi-brittle behaviour appears when the porosity rate reaches 60% and a decrease in mechanical properties as the porosity rate increased. At a porosity rate of 20%, a first alumina was produced with micrometric, interconnected pores, while a second was produced with isolated spherical and mesometric pores. The Young’s modulus is little affected by pore size and morphology, while failure stress decreases with increasing pore size. At iso-density, different grain arrangements lead to different fracture mechanisms despite a similar mechanical response: the more compact the grain arrangement, the more transgranular the crack propagation.Comparing failure tests on pharmaceutical tablets: Interpretation using experimental results and a numerical approach with cohesive zone models
http://hdl.handle.net/10985/25021
Comparing failure tests on pharmaceutical tablets: Interpretation using experimental results and a numerical approach with cohesive zone models
MAZEL, Vincent; GIRARDOT , Jeremie; KOPP, Jean-Benoit; MOREL, Stéphane; TCHORELOFF, Pierre
The mechanical strength is an important quality attribute of pharmaceutical tablets. It can be determined using different failure tests like the Brazilian test or the three-point bending test. Nevertheless, literature shows that different failure tests often give conflicting values of tensile strengths (TS), which are generally calculated using the maximum stress criterion as a failure criterion. This work started from the hypothesis that these discrepancies are in fact due to the application of this criterion which is not suited to study pharmaceutical tablets, first due to heterogeneity of the stress distributions during the tests and second due to the quasi-brittle nature of pharmaceutical tablets. As an alternative, a numerical fracture criterion which is known to be well-suited for quasi-brittle solids (cohesive zone model, CZM) was used and calibrated using experiments. Using this approach, the breaking forces obtained numerically were shown to be in fair agreement with the experimental ones. Above all, the numerical results made it possible to catch the trends when comparing the different failure tests one to another. Especially, the model made it possible to retrieve the factor 2 between the TS obtained by three-point bending and by diametral compression found in the literature.
Sat, 01 Jul 2023 00:00:00 GMThttp://hdl.handle.net/10985/250212023-07-01T00:00:00ZMAZEL, VincentGIRARDOT , JeremieKOPP, Jean-BenoitMOREL, StéphaneTCHORELOFF, PierreThe mechanical strength is an important quality attribute of pharmaceutical tablets. It can be determined using different failure tests like the Brazilian test or the three-point bending test. Nevertheless, literature shows that different failure tests often give conflicting values of tensile strengths (TS), which are generally calculated using the maximum stress criterion as a failure criterion. This work started from the hypothesis that these discrepancies are in fact due to the application of this criterion which is not suited to study pharmaceutical tablets, first due to heterogeneity of the stress distributions during the tests and second due to the quasi-brittle nature of pharmaceutical tablets. As an alternative, a numerical fracture criterion which is known to be well-suited for quasi-brittle solids (cohesive zone model, CZM) was used and calibrated using experiments. Using this approach, the breaking forces obtained numerically were shown to be in fair agreement with the experimental ones. Above all, the numerical results made it possible to catch the trends when comparing the different failure tests one to another. Especially, the model made it possible to retrieve the factor 2 between the TS obtained by three-point bending and by diametral compression found in the literature.