Thickness influence on a structural methacrylate adhesive behavior

Jaillon, Agathe

Jumel, Julien

Lachaud, Frédéric

Paroissien, Eric

Renart, Jordi

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											 	   		 	  	     	 			 									 an author's https://oatao.univ-toulouse.fr/19884Jaillon, Agathe and Jumel, Julien and Lachaud, Frédéric and Paroissien, Eric and Renart, Jordi Thickness influence ona structural methacrylate adhesive behavior. (2018) In: 6th World Congress on Adhesion and Related Phenomena(WCARP 2018), 25 February 2018 - 1 March 2018 (San Diego, United States). (Unpublished)www.institut-clement-ader.org Toulouse, Albi, Tarbes Thickness influence on a structural methacrylate adhesive behavior 1. Institut Clément Ader (ICA), Université de Toulouse, CNRS, INSA, ISAE-SUPAERO, MINES ALBI, UPS, F-31400 Toulouse, France 2. Université de. Bordeaux, Arts et Metiers ParisTech, CNRS, I2M, UMR 5295, F-33400 Talence, France  3. Universitat de Girona · Department of Mechanic Engineering and Industrial Construction · AMADE, Spain · Girona  Presented by: Agathe Jaillon1 WCARP 2018 – February 28  Co-authors: Julien Jumel2, Frédéric Lachaud1, Eric Paroissien1, Jordi Renart3 • agathe.jaillon@isae.fr • +335 61 17 12 14  2 www.institut-clement-ader.org Toulouse, Albi, Tarbes Context • Global project To develop an adhesive bond manufacturing process which ensure its reliability through supervision and numerical simulation of the part life cycle        • Scientific problematic • Characterization approaches for the evaluation and modeling of adhesive thickness influence on adhesive bond failure behavior Optimal design Charactérization Supervision Automated manufacturing Conformity control eMethacrylate structural adhesive 3 www.institut-clement-ader.org Toulouse, Albi, Tarbes Content • Context  • Experimental studies • Bulk adhesive tests • Arcan tests • DCB tests  • Numerical modeling of a DCB test  • Comparison between experimental and numerical test results   • Conclusions and perspectives  4 www.institut-clement-ader.org Toulouse, Albi, Tarbes Bulk adhesive manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Adhesive specification • Methacrylate structural adhesive SAF30MIB (Bostik)  • Bi composants thermoplastic adhesive in paste • Polymerization at room temperature for 24h   • Manufacturing protocol • PTFE mould • Specimen’s size 150x10x4mm [NF ISO 527-2] • Recovered by a polypropylene film  Bulk specimen manufacturing Cured specimen Inhibited by oxygen 5 www.institut-clement-ader.org Toulouse, Albi, Tarbes Bulk adhesive tensile tests Experimental Study Numerical Analysis Conclusions Results Comparison • Test condition • Monotonic test on an Instron 100kN • Speed rate : 5mm/min  • Measurements made by 3D digital image correlation (DIC)  E (MPa) υ ( - ) Smax (MPa) 614 (±143) 0.37 (±0,02) 11.8 (±1,6) 024681012140% 5% 10% 15% 20% 25% 30% 35%Stress (MPa) Strain ( % ) 6 www.institut-clement-ader.org Toulouse, Albi, Tarbes ARCAN specimen manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Specimen specifications • Massive adherends  • Round beaks [Cognard2005] • Bonded surface :  • 21x40mm • Surface preparation :  • degreasing with isopropanol • Calibrated thicknesses :  • 0.2mm and 1mm • Excess adhesive removed with a cylindrical spatula 7 www.institut-clement-ader.org Toulouse, Albi, Tarbes ARCAN specimen manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Specimen specifications • Massive adherends  • Round beaks [Cognard2005] • Bonded surface :  • 21x40mm • Surface preparation :  • degreasing with isopropanol • Calibrated thicknesses :  • 0.2mm and 1mm • Excess adhesive removed with a cylindrical spatula 8 www.institut-clement-ader.org Toulouse, Albi, Tarbes ARCAN specimen manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Specimen specifications • Massive adherends  • Round beaks [Cognard2005] • Bonded surface :  • 21x40mm • Surface preparation :  • degreasing with isopropanol • Calibrated thicknesses :  • 0.2mm and 1mm • Excess adhesive removed with a cylindrical spatula Thickness calibrator Positioning axis 9 www.institut-clement-ader.org Toulouse, Albi, Tarbes ARCAN specimen manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Specimen specifications • Massive adherends  • Round beaks [Cognard2005] • Bonded surface :  • 21x40mm • Surface preparation :  • degreasing with isopropanol • Calibrated thicknesses :  • 0.2mm and 1mm • Excess adhesive removed with a cylindrical spatula Adhesive 10 www.institut-clement-ader.org Toulouse, Albi, Tarbes 01002003004005006007000 5 10 15 20Von Mises Stress (MPa) Abscissa along the overlap (mm) No BeakTriangular beakRound Beak020040060080010001200no beak triangular beak round beakVon Mises stresses (MPa) Curved adhesiveStraight adhesive• Advantages of round beaks • Decrease edge’s stress concentration • Increase length where stress is constant  • Advantages of curved adhesive • Decrease stress concentration   validation of specimen geometry – FE model Experimental Study Numerical Analysis Conclusions Results Comparison • Stress at the edge  • Stress distribution Adherend Adhesive Adherend Adhesive L=15.7mm 11 www.institut-clement-ader.org Toulouse, Albi, Tarbes ARCAN tests Experimental Study Numerical Analysis Conclusions Results Comparison • Test conditions • Modified Arcan on Zwick 10kN • Digital image correlation on the adherends • Speed rate for t = 0.2mm: 0.1mm/min • Speed rate for t = 1mm: 0.2mm/min • Loadings : tension, shear and tension-shear • Matlab analysis Arcan experimental set-up DIC analysis Image correction Results Fixed substrat Movable substrat α Shear Tension 12 www.institut-clement-ader.org Toulouse, Albi, Tarbes Tension 024681012140 0.1 0.2 0.3 0.4Stress (Mpa) Strain ( % ) • Tension: α=0°   ARCAN Results Experimental Study Numerical Analysis Conclusions Results Comparison t (mm) Yt (MPa) Smax (MPa) 0.253(±0.06) 1650(±850) 10.56 (±0,24) 0.796 (±0.04) 1750 (unk.) 13.07 (±0,14) t=1mm t=0.2mm 13 www.institut-clement-ader.org Toulouse, Albi, Tarbes 024681012140% 10% 20% 30% 40%Stress (Mpa) Strain ( % ) 02468101214-5% 45% 95% 145% 195% 245% 295%Stress (MPa) Strain (%) Tension-shear • Tension: α=0°   ARCAN Results Experimental Study Numerical Analysis Conclusions Results Comparison • Shear α=90°   t=1mm t=0.2mm t=1mm t=0.2mm 45° t=1mm t (mm) Smax (MPa) εr (%) 0.183(±0.01) 12,51 (±0,11) 250 (±54) 0.765 (±0.21) 13.21 (±0,10) 119(±8) 14 www.institut-clement-ader.org Toulouse, Albi, Tarbes Tension-shear 024681012140 5 10 15Tensile stress (MPa) Shear stress (MPa) t=0.2mmt=1mm024681012140% 10% 20% 30% 40%Stress (Mpa) Strain ( % ) 02468101214-5% 45% 95% 145% 195% 245% 295%Stress (MPa) Strain (%) • Tension: α=0°   ARCAN Results Experimental Study Numerical Analysis Conclusions Results Comparison • Shear α=90°   • Failure envelope t=1mm t=0.2mm t=1mm t=0.2mm 0° 45° 90° t=1mm 15 www.institut-clement-ader.org Toulouse, Albi, Tarbes DCB specimen manufacturing Experimental Study Numerical Analysis Conclusions Results Comparison • Specimen specification • Adherends’ size : 195x15x10mm • Overlap length : 145mm • Initial crack : 35mm   • Calibrated thickness :  • 0.2mm and 1mm   DCB specimen assembly tool DCB adherends with PTFE film for thickness calibration PTFE film 16 www.institut-clement-ader.org Toulouse, Albi, Tarbes DCB tests Experimental Study Numerical Analysis Conclusions Results Comparison • Test conditions • On a Zwick 10kN • Speed rate: 2mm/min • Digital image correlation on both sides • Cohesive failure  DCB experimental set-up Full DCB specimen Adherend displacement Adherend rotation Openning measurement Crack tip initial crack tip taken up close 17 www.institut-clement-ader.org Toulouse, Albi, Tarbes  DCB results Experimental Study Numerical Analysis Conclusions Results Comparison • Load displacement curves • Hypothesis :  • No plastic strain in adherends • Adhesive behavior not time dependent  02004006008001000120014000 5 10 15Load (N) Opening at loading point δ (mm) t=0.35mm t=1mm Schematic representation of a DCB test θ θ h F F t 𝑎0 𝐿 𝛿 Adherends Adhesive • Comments:  • Modulus not thickness-dependent  • Crack propagation thickness-dependent  propagation initiation 18 www.institut-clement-ader.org Toulouse, Albi, Tarbes • Energy release rate • J integral computation   0246810120% 20% 40% 60% 80%Stress (MPa) Strain ( % ) ModelDCB 7DCB 5DCB 1θ θ h F F t 𝑎0 𝐿 𝛿 Adherends Adhesive 𝑱 =𝟐𝑭𝜽𝒃  DCB results Experimental Study Numerical Analysis Conclusions Results Comparison 00.511.522.533.544.550 5 10 15J (N/mm) Opening at loading point δ (mm) t=0.35mm t=1mm • Traction-separation law • Stress computation for t=0.2mm   𝝈 =𝒅𝑱𝒅𝜹 t  (mm) Yt  (MPa) Smax (MPa) GIc (J/m²) 𝜺𝒑  (%) 0.35  (±0,06) 762  (±162) 9.4  (±1,3) 1691  (±99) 82 (±19) t (mm) GIc (J/m²) 0.35 (±0,06) 1730 (±347) 1.31 (unk.) 4270 (±180) GIc [Andersson2004] 19 www.institut-clement-ader.org Toulouse, Albi, Tarbes  Strain-stress curves comparison Experimental Study Numerical Analysis Conclusions Results Comparison Test t  (mm) Yt  (MPa) Smax (MPa) A  (MPa) Tensile 3,96 (±1.6) 614 (±143) 11.8 (±1,6) 3.93 (±0.12) DCB 0.35  (±0,06) 762  (±162) 9.4  (±1,3) 4.83  (±0.8) ARCAN 0.253 (±0.06) 1650 (±850) 10.56 (±0,24) 2.57 (±1.8) • Comments • 3 kind of tests with different stress state • All tests have similar tendencies  • Modulus of the linear part are similar for DCB an tensile test • Arcan tests have a significantly higher Modulus • DCB and ARCAN tests have a similar plastic plateau • Softening part only measurable during DCB test 024681012140% 10% 20% 30% 40% 50% 60% 70%Stress (MPa) Strain (%) DCB ModelArcan testUni-axial tensil testWhich experimental results should be used for the numerical modeling of the adhesive failure behavior ? 20 www.institut-clement-ader.org Toulouse, Albi, Tarbes • Macro element [Lelias2015]  • 1D Implemented in scilab • 200 BBE in overlap length  • Cohesive zone model • Bilinear law as first approximation • Trapezoid law identified in DCB tests Damage initiation Strain Damage propagation GIc Yt Stress Smax Beam Element DCB models Experimental Study Numerical Analysis Conclusions Results Comparison Bonded Beam Element (BBE) 1st  BBE ith  BBE Damage initiation Strain Damage propagation GIc Yt Stress Smax 𝜀𝑝 𝜀𝑝 𝜀𝑠 𝜀𝑖  𝜀𝑖  (σ, ε) (σ, ε) 21 www.institut-clement-ader.org Toulouse, Albi, Tarbes 0200400600800100012000 1 2 3 4Load (N) Openning at loading point (mm) EXP EXPBilinear CZM Bilinear CZMTrilinear CZM Trilinear CZMt = 1 mm t = 0.2 mm 0123456789100 25 50 75 100 125Stress (MPa) Strain (%) BilinearTrilineart = 0.2 mm Stress (MPa) Bilinearili Trilineart = 1 mm 02004006008001000120014000 5 10 15Applied Load(N) Opening at loading point (mm) Experimental dataBilinear CZMTrilinear CZM02004006008001000120014000 5 10 15Applied Load(N) pening at l a i g i t ( ) Experi ental data Experimental dataBilinear CZ Bilinear CZMTrilinear CZ Trilinear CZMNumeric VS experimental Experimental Study Numerical Analysis Conclusions Results Comparison • Traction-separation law • Propagation correctly predicted  • Stiffness correctly predicted • Inverse method to find CZM for 1mm-bond • Load-openning curves Adhesive thickness (mm) Yt  (MPa) Smax (MPa) GIc  (J/m²) 0.35 710 9.5 1950 1.31 710 9.5 4000 0123456789100% 20% 40% 60% 80% 100% 120%Stress (MPa) Strain (%) BilinearTrilinear100200300400500600700800900Load (N) 22 www.institut-clement-ader.org Toulouse, Albi, Tarbes Conclusions & prospects Experimental Study Numerical Analysis Conclusions Results Comparison • Experimental results • Characterization of the adhesive failure behavior  • 3 differents tests : tensile on bulk adhesive, ARCAN  and DCB  • 2 thicknesses: 0.2mm and 1mm • Identifiaction of different stress-strain curves dependant on the stress state of the test • Adhesive thickness influence on the failure behavior ? • Increase of the energy release rate GIc • Increase of plastic plateau value • Increase of strain at failure in shear • Numerical modeling • Implementation of a bilinear and trilinear TS law in a ME model • TS law identified for 0.2mm-bond not directly usable for 1mm-bond • Perspectives • Experimental Identification of 1mm to 5mm-bond traction separation law • Sensivity study of CZM parameters • Implementation of a elasto-viscoplatic cohesive element   www.institut-clement-ader.org Toulouse, Albi, Tarbes Thank you for your attention 24 www.institut-clement-ader.org Toulouse, Albi, Tarbes References 1. Norme, N.F EN ISO 527-2, Plastiques-Détermination des propriétés en traction-Partie 2: Conditions d'essai des plastiques pour moulage et extrusion, 2012  2. Cognard, J. Y.; Davies, P.; Gineste, B. & Sohier, L. Development of an improved adhesive test method for composite assembly design, Composites Science and Technology, 2005, 65, 359-368  3. Andersson, T. & Stigh, U. The stress--elongation relation for an adhesive layer loaded in peel using equilibrium of energetic forces, International Journal of Solids and Structures, 2004, 41, 413-434  4. Lelias, G.; Paroissien, E.; Lachaud, F.; Morlier, J.; Schwartz, S. & Gavoille, C. An extended semi-analytical formulation for fast and reliable mode I/II stress analysis of adhesively bonded joints, International Journal of Solids and Structures, Elsevier, 2015, 62, 18-38     

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Thickness influence on a structural methacrylate adhesive behavior

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