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  • 1.
    Islam, Md Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Blekinge Institute of Technology.
    Fracture and Delamination in Packaging Materials: A Study of Experimental Methods and Simulation Techniques2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Packages are the means of preservation, distribution and convenience of use for food, medicine and other consumer products. The introduction of a new package-opening technique for a better opening experience requires additional prototype development and physical testing. In order for the design process to be more rapid and robust, finite element (FE) simulations are widely used in packaging industries to compliment and reduce the amount of physical testing.

    The goal of this work is to develop some building blocks for complete package-opening FE-simulation. To begin with, the study focuses on mechanical testing of packaging materials’ fracture and delamination; especially shear fracture. Use of tools like digital image correlation (DIC) and scanning electron microscope (SEM) greatly aided to the strain measuring technique and observation of fractured and delaminated surfaces respectively.

    A modified shear test specimen for polymer sheet testing was developed and its geometry was optimized by FE-simulation. A geometry correction factor of shear fracture toughness for the proposed specimen was derived based on linear elastic fracture mechanics (LEFM). It was found that the specimen ligament length should vary between twice the thickness and half the ligament width of the modified shear specimen to measure the essential work of fracture.

    Thin-flexible laminate of low-density polyethylene (LDPE) and aluminium (Al) is another key packaging material addressed in this study. The continuum and fracture testing of individual layers provided the base information and input for FE-modelling. The FE-simulation material parameters were calibrated from the physical test response through inverse analysis. Identification process of the laminate interface fracture energy (Gc) from peel tests was studied experimentally and theoretically. A successful FE-simulation optimization framework using artificial neural network and genetic algorithm was developed for the calibration of Gc. To address the challenge in quantifying shear Gc of laminate with very thin substrates, a convenient test technique was proposed. In a separate case, the tearing response of LDPE/PET (polyethylene terephthalate) laminate was studied to examine crack propagation, crack path deviation and delamination of the laminate in mode III fracture. Several tear EWF evaluation theories were proposed along with a cyclic tear test method.

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    fulltext
  • 2.
    Islam, Md. Shafiqul
    Blekinge Institute of Technology.
    Shear Fracture and Delamination in Packaging Materials: A study of Experimental Methods and Simulation Techniques2016Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Packages are the means of preservation, distribution and convenience of use for food, medicine and other consumer products. Package opening is becoming complicated in many cases because of cutting cost in design and production of opening techniques. Introduction of new package opening technique, material or geometry for better opening experience, forces new design measurements which require a large number of prototype developments and physical testing. In order to achieve more rapid and accurate design, Finite Element Method (FEM) Simulations are widely used in packaging industries to compliment and reduce the number of physical testing.

    The goal of this work is to develop the building blocks towards complete package opening simulation. The study focuses on testing and simulation of shear fracture and shear delamination of packaging materials. A modified shear test specimen was developed and optimized by finite element simulation. Test method was validated for High-density polyethylene (HDPE) and Polypropylene (PP). The developed method has been accepted by international standards organization ASTM. Based on linear elastic fracture mechanics, a geometry correction factor of shear fracture toughness for the proposed specimen was derived. The study concluded that, for ease of opening, HDPE is a more favorable material for screw caps than PP. When performing the experiment with the shear specimen to find essential work of fracture, the ligament length should be varied between twice of the thickness and half of the width of the specimen ligament.

    Multi-layered thin laminate of Low-density polyethylene (LDPE) and aluminum (Al), also known as Al/LDPE laminate, is another key object addressed in this study. Continuum and fracture testing of individual layers provided the base information and input for numerical modeling. The propagation of an interfacial pre-crack in lamination in Al-LDPE laminate was simulated using several numerical techniques available in the commercial FEM solver ABAQUS, and it was concluded that using the combination of VCCT technique to model the interfacial delamination and coupled elasto-plastic damage constitutive for Al and LDPE substrates can describe interfacial delamination and failure due to necking. It was also concluded that the delamination mode in a pre-crack tip is influenced by the ratio of fracture energy release rate of mode I and II. To address the challenge in quantifying shear energy release rate of laminate with very thin substrate, a convenient test technique is proposed. Additionally, scanning electron microscopic study provided useful information on fractured and delaminated surfaces and provided evidence that strengthened the conclusions of this work.

    The proposed test methods in this work will be crucial to measure the shear mechanical properties in bulk material and thin substrates. Laminates of Al and LDPE or similar material can be studied using the developed simulation technique which can be effectively used for decision support in early package development.

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    fulltext
  • 3.
    Islam, Md. Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Simulation of Laminates and a Modified Shear Test Specimen2015Övrigt (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    Poster
  • 4.
    Islam, Md Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Blekinge Institute of Technology.
    Alfredsson, Svante
    Univ Skovde, SWE.
    Peeling of metal foil from a compliant substrate2019Ingår i: The journal of adhesion, ISSN 0021-8464, E-ISSN 1563-518XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for 180degree being slightly higher than for 90degree. The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent.

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    Article_Peel
  • 5.
    Islam, Md. Shafiqul Islam
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Zhang, Defeng
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mehmood, Nasir
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Study of Shear Dominant Delamination in Thin Brittle-High Ductile Interface2015Ingår i: National Agency for Finite Element Methods and Standards (NAFEMS), 2015Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Thin laminates of Aluminum (Al) and Low Density Polyethylene (LDPE) is an essential constituent of food packages where these two substrates are bonded together with a thin layer of LDPE acting as adhesive. Noticeably, Al is a low ductile/quasi brittle material whereas, LDPE is highly ductile.  The mechanism of delamination and strength of bond between the interfaces dictates the continuum and damage behaviour of this composite. However, measuring the shear delamination is challenging as conventional test methods have limitations when the substrates are very thin. This study explains a method that uses uniaxial tensile testing on the pre-cracked specimen of this composite to find energy dissipation due to shear delamination and successfully use it in Finite Element Simulation in Abaqus. The delamination was observed in a narrow strip region close to fracture surfaces and measured with special visualization aid. Similar response was found in FEM simulation. Scanning Electron Microscopic (SEM) study of delaminated interface confirms the domination of shearing. In a cohesive zone modelling in Finite Element Simulation software, the shear delamination energy was used as input parameter along with an arbitrary bi-linear cohesive law. The substrates’ constitutive response was modelled considering non linear plasticity and softening. Finally proposed delamination energy separation method was validated with comparison between the physical tests and FEM simulations.

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    fulltext
  • 6.
    Islam, Md Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Blekinge Institute of Technology.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Trouser tear testing of thin anisotropic polymer films and laminates2019Ingår i: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 219, nr 2, s. 187-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This research has investigated the essential work of fracture (EWF) from trouser tear test of polyethylene terephthalate (PET), low-density polyethylene (LDPE) films and their corresponding laminate using a convenient cyclic tear test method. Propagation of tear crack in these thermoplastics deflects from the initial crack path due to the material anisotropy. An improvement to a two-zone tear model for determining tear EWF was proposed for LDPE-like materials. Energy dissipation due to non-uniform bending of the trouser-legs was determined to be significant in EWF calculation of tearing and this was therefore considered in this study. To measure the tear EWF in laminates, contribution from delamination energy dissipation was accounted for.

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    Trouser tear testing_Islam
  • 7.
    Islam, Md. Shafiqul
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Chen, Xin
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Deng, Hong Yu
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Innovation for and by the People with Disabilities: A Case Study in Improvement of the Manual Wheelchair2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper focuses on information-driven engineering, where information is gathered by means of innovation for people and by the people. This case study was carried out on innovation of a manual wheelchair. Through active participation of person with disability (direct users) and their carers (indirect user), knowledge awareness of the early design was increased. Computer aided engineering tools were used for the development of virtual prototype (VP) and after further feedback from direct and indirect users design was adjusted. Additionally, Physical prototype was built to practically demonstrate the new features to users and finally the prototype was readjusted to bridge user requirement even more. This innovation process identifies additional improvement aspects and contributes beyond fundamental personal needs and increases well being.

    Ladda ner fulltext (pdf)
    fulltext
  • 8.
    Islam, Md. Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Jian, Li
    Mehmood, Nasir
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Study of Shear Property of HDPE by Experiment and Simulation2014Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Syftet med detta arbete är att utvärdera effekten av olika provdimension och spricka längden på de mekaniska egenskaperna hos HDPE (High Density Polyethylene) som ofta används inom förpackningsindustrin. I den experimentella delen, är två exemplar som valts. En är hund-ben formade drag exemplar för att hitta dragmaterialegenskaper. Den andra är modifierad skjuvning exemplar för att studera skador skjuvning. En motsvarande numerisk simulering görs genom att tillämpa en kommersiell Finite Element Analysis (FEA)-programmet ABAQUS. Vidare har den mikroskopiska analysen utförs för att observera frakturytan av provet efter testet med svepelektronmikroskop (SEM). En serie experiment och simulering bearbetades och resultaten visar att fraktur initiering och utbredningsbeteende i skjuvning provet är känslig för storleken på den pre-crack (hack) och skjuvtöjning vid brott.

    Ladda ner fulltext (pdf)
    fulltext
  • 9.
    Islam, Md. Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Shanghai Second Polytechnic Univ., Faculty of Mech. & El. Eng., 201209, Shanghai, China.
    Yang, Geng
    Kungliga Tekniska högskolan, SWE.
    Study of Ligament Length Effect on Mode Mix of a Modified In-Plane Shear Test Specimen2016Ingår i: Materials Performance and Characterization, E-ISSN 2165-3992, ISSN 2165-3992, Vol. 5, nr 3, s. 249-259Artikel i tidskrift (Refereegranskat)
    Abstract [sv]

    Shear brottseghet är ett viktigt material beteende som måste bestämmas och beaktas i många industriella områden. Samtidigt, testar skjuvning en av de komplexa materialtestområden där tillgängliga metoder är få, ofta behöver specialarrangemang, och de flesta av de metoder som inte strikt uppfyller definitionen av ren skjuvning. I denna studie var en modifierad skjuvning provstycket föreslås att mäta skjuv-brottsegheten genom enaxlig belastning i en dragprovningsmaskin. Högdensitetspolyeten (HDPE) användes som testmaterial för experimenten. Provet skapades för att passa den vanligaste använda dragtestmaskin. Provet därefter optimeras med användning av finit elementanalys (FEA) för att hitta den geometrin och storleken av för-hack för att undvika den blandat läge lastning och minimera effekterna av normala påkänningar. För provet i diskussionen kan hittas en övre och undre gräns för användbar ligament längd. En metod för att bestämma brottsegheten diskuterades i enlighet med den väsentliga brottarbetet. Slutligen ett exempel på en speciell tillämpning av den föreslagna provet presenteras där variationen av skjuvhållfastheten kontrollerad delamineringsmaterial (CDM) mättes.

    Ladda ner fulltext (pdf)
    Submitted version
  • 10.
    Islam, Md. Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Zhang, Defeng
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mehmood, Nasir
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Study of Shear Dominant Delamination in Thin Brittle-High Ductile Interface2016Ingår i: 21ST EUROPEAN CONFERENCE ON FRACTURE, (ECF21) / [ed] Francesco Iacoviello, Elsevier, 2016, Vol. 2, s. 152-157Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Tunna laminat av aluminium (Al) folie och lågdensitetspolyeten (LDPE) film är väsentliga beståndsdelar i livsmedelsförpackningar, där dessa två substrat är sammanbundna med ett tunt skikt av LDPE som fungerar som bindemedel. Märkbart är Al en låg segt / kvasi sprött material, medan LDPE är mycket formbart. Mekanismen för delaminering och styrka bindningen mellan gränssnitten dikterar kontinuum och skador beteende denna komposit. Men mäta skjuvning delamineringsegenskaper är utmanande som konventionella testmetoder har begränsningar när substraten är mycket tunn och flexibel. Denna studie förklarar en preliminär metod som använder enaxlig dragprovning på förhand spruckna exemplar av denna komposit för att hitta energiupptagning på grund av skjuvning delaminering och framgångsrikt använder den i finita elementsimulering i Abaqus. Delamineringen observerades i en smal remsliknande region nära brottytor och mättes med särskild visualisering stöd. Ett liknande svar återfanns i FEM simulering. Svepelektronmikroskop (SEM) studie av delaminerat gränssnitt bekräftar delaminering att vara skjuvning i naturen. I en sammanhängande zon modellering i Abaqus, var den uppmätta skärdelaminering energi som används som inparameter tillsammans med en godtycklig bilinjär sammanhängande lag för validering av experimentella mätningen.

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    Published ECF21
  • 11.
    Islam, Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Yang, Geng
    Measuring Shear Fracture Toughness with a Modified Shear Test Specimen2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Shear fracture toughness is an important material behavior that needs to be determined and considered in many industrial fields. At the same time, shear testing is one of the complex material testing areas where available methods are few and often need special arrangements. In this study, a modified shear test specimen was proposed to measure the shear fracture toughness by uniaxial loading in a tensile testing machine. High Density Polyethylene (HDPE) was used as test material for the experiments. The specimen was created in order to suit the most common used tensile test machine. The specimen was than optimized by using Finite Element Analysis (FEA) to find the geometry and the size of the pre-crack to avoid the mixed mode loading and minimize effect of normal stresses. For the specimen in discussion, an upper and lower limit of useable ligament length can be found. Finally, a method for determining the fracture toughness was discussed according to essential work of fracture.

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    fulltext
  • 12.
    Islam, Shafiqul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Khan, Abdullah
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Jian, Li
    A Study of Shear Stress Intensity Factor of PP and HDPE by a Modified Experimental Method together with FEM2013Ingår i: International Journal of Mechanical, Aerospace, Industrial and Mechatronics Engineering, ISSN 2010-376X, Vol. 7, nr 11Artikel i tidskrift (Refereegranskat)
    Abstract [sv]

    Shear testning är en av de mest komplexa testområden där tillgängliga metoder och prov geometrier skiljer sig från varandra. Därför en modifierad skjuvförsök exemplar (MSTS) kombinerar det enkla enaxlade test med en zon av intresse (ZOI) testas som ger nästan ren skjuvning. I denna studie är materialparametrar av polypropen (PP) och polyeten med hög densitet (HDPE) först mätt med dragprov med en hundbensformade prov. Dessa parametrar används sedan som underlag för den finita elementanalys. För det andra är en specialdesignad exemplar (MSTS) som används för att utföra de skjuvning stresstester i en dragprovmaskin för att få resultat i form av krafter och förlängning, sprickinitiering etc. Svepelektronmikroskopi (SEM) utförs också på skjuvbrott ytan för att finna material beteende. Dessa experiment sedan simuleras genom finita elementmetoden och jämföras med de experimentella resultaten i syfte att bekräfta den simuleringsmodell. Shear spänningstillstånd inspekteras för att hitta användbarheten av de föreslagna bryt provet. Slutligen kan ett geometrikorrektionsfaktor fastställas för dessa två material i detta specifika lastning och geometri med nagg använder Linear Elastic Brottmekanik (LEFM). Av dessa resultat, stam energi av skjuvbrott och spänningsintensitetsfaktor (SIF) i skjuvning av dessa två polymerer diskuteras i särskild ansökan av skruvkork öppnandet av medicinska eller matpaket med ett temperament bevis säkerhetslösning.

    Ladda ner fulltext (pdf)
    fulltext
  • 13.
    Shahmardani, Mahdieh
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Ståhle, Per
    Lund University, SWE.
    Islam, Md Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Numerical simulation of buckling and post-buckling behavior of a central notched thin aluminum foil with nonlinearity in consideration2020Ingår i: Metals, ISSN 2075-4701, Vol. 10, nr 5, artikel-id 582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In thin notched sheets under tensile loading, wrinkling appears on the sheet surface, specifically around the cracked area. This is due to local buckling and compression stresses near the crack surfaces. This study aims to numerically study the buckling behavior of a thin sheet with a central crack under tension. A numerical model of a notched sheet under tensile loading is developed using the finite element method, which considers both material and geometrical nonlinearity. To overcome the convergence problem caused by the small thickness-to-length/width ratio and to stimulate the buckling, an imperfection is defined as a small perturbation in the numerical model. Both elastic and elasto-plastic behavior are applied, and the influence of them is studied on the critical buckling stress and the post-buckling behavior of the notched sheet. Numerical results for both elastic and elasto-plastic behavior reflect that very small perturbations need more energy for the activation of buckling mode, and a higher buckling mode is predominant. The influences of different parameters, including Poisson’s ratio, yield limit, crack length-to-sheet-width ratio, and the sheet aspect ratio are also evaluated with a focus on the critical buckling stress and the buckling mode shape. With increase in Poisson’s ratio. First, the critical buckling stress reduces and then remains constant. A higher yield limit results in increases in the critical buckling stress, and no change in the buckling mode shape while adopting various crack length-to-sheet-width ratios, and the sheet aspect ratio changes the buckling mode shape.

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    Numerical simulation of buckling and post-buckling behavior of a central notched thin aluminum foil with nonlinearity in consideration
  • 14.
    Zhang, De-Feng
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Islam, Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Modeling and Study of Fracture and Delamination in a Packaging Laminate2016Ingår i: PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON MATERIAL ENGINEERING AND APPLICATION (ICMEA 2016) / [ed] Jou, J H, ATLANTIS PRESS , 2016, s. 408-414Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work, a packaging laminate consisting of LDPE (Low Density Polyethylene), Alfoil (Aluminum foil) is focused, and failure due to necking in substrates and interfacial delamination under loading are considered. A coupled elasto-plasticity damage and fracture constitutive model is combined. The proposed constitutive model is incorporated into the FEM code ABAQUS and utilized to simulate a uniaxial tension in the laminate with an interfacial pre-crack. The simulation results show deformation of the laminate agrees well with theoretical results. The new combined constitutive model is proper to study the failure due to necking and interfacial delamination in the laminate. And the interfacial delamination mode in pre-crack tip could be influenced by fracture toughness ratio of mode I, II.

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    fulltext
  • 15.
    Zhang, Defeng
    et al.
    College of Mech. Eng., Quzhou University, 324000 Quzhou, China.
    Mao, Kunming
    Dassault Systemes SIMULIA Corp, West Lafayette, Indiana, USA.
    Islam, Md. Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Tetra Pak Packaging Solutions AB.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Fac. of Mech. & El. Eng., Shanghai Second Polytechnic Univ., 201209 Shanghai, China.
    Powerful Modelling Techniques in ABAQUS to Simulate Failure of Laminated composites2016Rapport (Refereegranskat)
    Abstract [en]

    In this study, laminated composites consisting of LDPE (Low Density Polyethylene), Al-foil (Aluminum foil)and an adhesive interface layer is focused. The defects like necking in LDPE, Al-foil layer and interfacial delaminationcan significantly impact the loading capacity of the laminated material. However, the influence mechanisms of thedefects are still unclear, and no appropriate research tool is available. Therefore, the FEM model based on alreadyavailable techniques in ABAQUS is developed in this work. The aim with the model is to create a robust numericalanalysis tool for further research work.In the modelling process, possibility of necking in substrates and interfacial delamination between material layers isconsidered. A coupled elasto-plasticity damage constitutive model, based on Hooke’s Law, the J2 yield criterion,isotropic hardening, associated flow-rule and ductile damage model, is formulated to demonstrate necking behaviorof substrates. In ABAQUS, three modelling techniques, namely VCCT, Cohesive Element, and XFEM, have been usedto simulate interfacial delamination. The simulation results are compared with the theoretical results.A uniaxial tension test consisting of a two material laminate is simulated by using these three modelling techniques.The special modelling skills for respective modelling techniques, element type, meshing technique of each model, arealso introduced. The comparison with the theoretical results shows necking in substrates and interfacial delaminationare also achieved in all three models as expected. Deformation results of the simulation are very close to that of thetheoretical analysis. Technique features of VCCT, Cohesive Element and XFEM in modelling of interfacialdelamination are analyzed and concluded. These three FEM models can all be utilized according to the requirementsof subsequent research.

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  • 16.
    Zhang, Defeng
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mao, Kunming
    Dassault Systemes SIMULIA Corp.
    Islam, Md. Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mehmood, Nasir
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Powerful Modelling Techniques in Abaqus to Simulate Necking and Delamination of Laminated Composites2015Övrigt (Övrigt vetenskapligt)
    Abstract [en]

    In this study, laminated composites consisting of LDPE (Low Density Polyethylene), Al-foil (Aluminum foil) and an adhesive interface layer is focused. The defects like necking in LDPE, Al-foil layer and interfacial delamination can significantly impact the loading capacity of the laminated material. However, the influence mechanisms of the defects are still unclear, and no appropriate research tool is available. Therefore, the FEM model based on already available techniques in ABAQUS is developed in this work. The aim with the model is to create a robust numerical analysis tool for further research work.

    In the modeling process, possibility of necking in substrates and interfacial delamination between material layers is considered. The constitutive material behaviour is elastic-plastic complemented with progressive damage, based on Hooke’s Law, the J2 yield criterion, isotropic hardening, associated flow-rule and ductile damage model are formulated to demonstrate necking behavior of substrates. In ABAQUS, three modeling techniques, namely VCCT, Cohesive Element, and XFEM, have been used to simulate interfacial delamination. The simulation results are compared with the theoretical results.

    A uniaxial tension test consisting of a two material laminate is simulated by using these three modeling techniques. The special modelling skills for respective modeling techniques, element type, meshing technique of each model, are also introduced. The comparison with the theoretical results shows necking in substrates and interfacial delamination are also achieved in all three models as expected. Deformation results of the simulation are very close to that of the theoretical analysis. Technique features of VCCT, Cohesive Element and XFEM in modelling of interfacial delamination are analyzed and concluded. These three FEM models can all be utilized according to the requirements of subsequent research.

    Ladda ner fulltext (pdf)
    Powerful Modelling Techniques in Abaqus to Simulate Necking and Delamination of Laminated Composites by Zhang-20151008
  • 17.
    Zhang, Tianqi
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Xu, Weilong
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Islam, Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Wu, Xing
    Kunming Inst Sci & Technol, CHN.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Handy Wheel Chair to help Disabled People Get into the Car2016Ingår i: PROCEEDINGS OF THE 2015 INTERNATIONAL SYMPOSIUM ON MATERIAL, ENERGY AND ENVIRONMENT ENGINEERING (ISM3E 2015), Atlantis Press , 2016, , s. 3Konferensbidrag (Refereegranskat)
    Abstract [en]

    A wheelchair with a gear system was designed and analysed in order to find a good solution for people with wheelchair to move into the car. This gear system has been designed to be installed in the car and the whole wheelchair can be moved into the car automatically even with the people on it. The three dimensional design have been done in a CAD commercial program with this the solid mechanics analysis was also performed. Volvo XC 60 and V60 as well as a foldable wheelchair have been chosen in this work.

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