Pub Date : 2021-09-01DOI: 10.23967/composites.2021.050
S. Arnold-Keifer, M. Imbert, N. Gross, M. May
Organosheets are multi-layer thermoplastic composites rapidly gaining interest in the automotive industry due to their ability to replace metallic sheets in lightweight applications. However, the current recycling approach for these materials mainly consists in strongly damaging mechanical processing such as grinding or shredding [1]. This leads to the loss of fibre length and alignment, which were causing the high mechanical properties of the original material. Therefore, the recycled material cannot be reused for the same application. However, the thermoplastic composites feature the major advantage of being reprocessable which would for example enable to reuse laminae (in polymer embedded unitary reinforcement layers) for the same application or as reinforcing patches if they could be recovered without significant damage from the multi-layer structure. In this context, the motivation of the presented work is to use a fracture mechanics framework to design a new high-quality recycling process based on the controlled delamination of organosheet laminae. The focus of this work is the use of peeling to recover minimally damaged laminae. To reach this goal, an analytical model describing the peeling process, accounting for the cohesive zone ahead of the crack tip as well as for the loading state and damage in the peeling arm is developed. The model is used to investigate the relative influence of the material properties and applied loads on crack propagation. For various sets of material properties, various types of loads as axial loads or normal loads located at various positions on the peel arm are tested. Crack propagation and potential damages induced in the peel arm by the applied loads are outputs of the sensitivity analyses. These analyses enable identifying quantitatively the loading conditions ensuring separation with a minimal damage of the recovered lamina.
{"title":"Towards Controlled Peeling as a Process to Recover Reusable Organosheet Laminae","authors":"S. Arnold-Keifer, M. Imbert, N. Gross, M. May","doi":"10.23967/composites.2021.050","DOIUrl":"https://doi.org/10.23967/composites.2021.050","url":null,"abstract":"Organosheets are multi-layer thermoplastic composites rapidly gaining interest in the automotive industry due to their ability to replace metallic sheets in lightweight applications. However, the current recycling approach for these materials mainly consists in strongly damaging mechanical processing such as grinding or shredding [1]. This leads to the loss of fibre length and alignment, which were causing the high mechanical properties of the original material. Therefore, the recycled material cannot be reused for the same application. However, the thermoplastic composites feature the major advantage of being reprocessable which would for example enable to reuse laminae (in polymer embedded unitary reinforcement layers) for the same application or as reinforcing patches if they could be recovered without significant damage from the multi-layer structure. In this context, the motivation of the presented work is to use a fracture mechanics framework to design a new high-quality recycling process based on the controlled delamination of organosheet laminae. The focus of this work is the use of peeling to recover minimally damaged laminae. To reach this goal, an analytical model describing the peeling process, accounting for the cohesive zone ahead of the crack tip as well as for the loading state and damage in the peeling arm is developed. The model is used to investigate the relative influence of the material properties and applied loads on crack propagation. For various sets of material properties, various types of loads as axial loads or normal loads located at various positions on the peel arm are tested. Crack propagation and potential damages induced in the peel arm by the applied loads are outputs of the sensitivity analyses. These analyses enable identifying quantitatively the loading conditions ensuring separation with a minimal damage of the recovered lamina.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126309677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.094
M. Richter, H. Dell, G. Oberhofer, H. Gese, F. Duddeck
{"title":"Material Modling of Textile Reinforced Composites with Respect to Fracture Initiation and Strain Rate Sensitivity","authors":"M. Richter, H. Dell, G. Oberhofer, H. Gese, F. Duddeck","doi":"10.23967/composites.2021.094","DOIUrl":"https://doi.org/10.23967/composites.2021.094","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125161016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.043
B. Tijs, A. Turón, C. Bisagni
This presentation summarizes the numerical and experimental evaluation of the failure behavior of thermoplastic composites, which are joined by means of conduction welding. The research supports the development of a next generation thermoplastic multi-functional fuselage [1]. The use of these new materials and fastener-free joints introduces new challenge as the strength of the welded joint is highly dependant on the strength and failure behavior of the thermoplastic matrix. A simplified modelling strategy that only accounts for a cohesive zone at the weld is compared to a high-fidelity model that takes into account the physical failure mechanisms at the lamina level. It was found that the joint strength is highly influenced by the failure mechanisms of not only the welded interface but also the surrounding plies. The high-fidelity modelling methodology is able to predict the failure mode of these welded joints with high accuracy with respect to the results obtained experimentally as shown in Figure 1.
{"title":"Failure of Thermoplastic Composite Welded Joints","authors":"B. Tijs, A. Turón, C. Bisagni","doi":"10.23967/composites.2021.043","DOIUrl":"https://doi.org/10.23967/composites.2021.043","url":null,"abstract":"This presentation summarizes the numerical and experimental evaluation of the failure behavior of thermoplastic composites, which are joined by means of conduction welding. The research supports the development of a next generation thermoplastic multi-functional fuselage [1]. The use of these new materials and fastener-free joints introduces new challenge as the strength of the welded joint is highly dependant on the strength and failure behavior of the thermoplastic matrix. A simplified modelling strategy that only accounts for a cohesive zone at the weld is compared to a high-fidelity model that takes into account the physical failure mechanisms at the lamina level. It was found that the joint strength is highly influenced by the failure mechanisms of not only the welded interface but also the surrounding plies. The high-fidelity modelling methodology is able to predict the failure mode of these welded joints with high accuracy with respect to the results obtained experimentally as shown in Figure 1.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122138771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.055
K. Yamamoto, M. Somemiya, S. Matsubara, N. Hirayama, K. Terada
{"title":"Distortional Hardening Material Model for Unidirectioally Reinforced CFRTP Considered from the Results of Numerical Material Testing","authors":"K. Yamamoto, M. Somemiya, S. Matsubara, N. Hirayama, K. Terada","doi":"10.23967/composites.2021.055","DOIUrl":"https://doi.org/10.23967/composites.2021.055","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133993639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.070
M. Fagerstr¨om, G. Catalanotti, P. K. Dileep, Stefan Hartmann, Tobias Fischer, Gerhard Ziegmann, Wei Hua, Heinz Palkowski
The practical application of light-weight structures in the form of sandwich structures is of particular interest in structural, automotive, marine, and aviation industries. We investigate metal/polymer/metal (MPM) sandwich structures, which show complex response when subjected to metal forming processes due to varying material characteristics within the layers. To evaluate the forming processes of sandwich structures, constitutive models for the face sheets made of heat treated steel of deep drawing quality and the core layer made of PA6 polymer are a prerequisite. For a first instance, a finite strain viscoplasticity model as proposed in [1, 2] is chosen. For the core layer, an extended constitutive model as shown in [3] will be proposed. This is based on a thermo-mechanically consistent finite strain overstress-type viscoplasticity model representing the material behavior of PA6. In this regard, a number of experiments are shown, which are the basis of the model. Both constitutive models contain material parameters, which are identified by tensile tests investigating rate-dependent, long term relaxation, and multi-step relaxation behavior performed at room temperature, see for a possible procedure [4]. In the final step, the constitutive models for steel and PA6 are numerically validated using deep drawing and bending experiments of MPM sandwich structures.
{"title":"Constitutive Modeling and Finite Element Simulation of Metal-Polymer-Metal Sandwich Structures","authors":"M. Fagerstr¨om, G. Catalanotti, P. K. Dileep, Stefan Hartmann, Tobias Fischer, Gerhard Ziegmann, Wei Hua, Heinz Palkowski","doi":"10.23967/composites.2021.070","DOIUrl":"https://doi.org/10.23967/composites.2021.070","url":null,"abstract":"The practical application of light-weight structures in the form of sandwich structures is of particular interest in structural, automotive, marine, and aviation industries. We investigate metal/polymer/metal (MPM) sandwich structures, which show complex response when subjected to metal forming processes due to varying material characteristics within the layers. To evaluate the forming processes of sandwich structures, constitutive models for the face sheets made of heat treated steel of deep drawing quality and the core layer made of PA6 polymer are a prerequisite. For a first instance, a finite strain viscoplasticity model as proposed in [1, 2] is chosen. For the core layer, an extended constitutive model as shown in [3] will be proposed. This is based on a thermo-mechanically consistent finite strain overstress-type viscoplasticity model representing the material behavior of PA6. In this regard, a number of experiments are shown, which are the basis of the model. Both constitutive models contain material parameters, which are identified by tensile tests investigating rate-dependent, long term relaxation, and multi-step relaxation behavior performed at room temperature, see for a possible procedure [4]. In the final step, the constitutive models for steel and PA6 are numerically validated using deep drawing and bending experiments of MPM sandwich structures.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126002344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.067
C. Schneider, G. Pinter
{"title":"Optimization of Specimen and Tabs Geometry for Quasi-Static and Fatigue Testing of Composites in UD 90° Laminates","authors":"C. Schneider, G. Pinter","doi":"10.23967/composites.2021.067","DOIUrl":"https://doi.org/10.23967/composites.2021.067","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131850979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.102
F. Turon, F. Otero, J. Freitas, van Hengel, H. C. D. Frel, X. Martinez
Glass Laminate Aluminum Reinforced Epoxy (GLARE) is a laminate within the Fibre Metal Laminates (FML) family which consists in a combination of very thin aluminium sheets and composite glass-fibre/epoxy-resin layers. This FML is widely used in the aeronautical sector because, compared to aluminium material, it provides a better structural strength and fatigue resistance, along with a better impact and corrosion resistance.
{"title":"The Impact of the Curing and Post-Stretching Process on the Stresses Distribution Around an Open Hole in Glare Laminate","authors":"F. Turon, F. Otero, J. Freitas, van Hengel, H. C. D. Frel, X. Martinez","doi":"10.23967/composites.2021.102","DOIUrl":"https://doi.org/10.23967/composites.2021.102","url":null,"abstract":"Glass Laminate Aluminum Reinforced Epoxy (GLARE) is a laminate within the Fibre Metal Laminates (FML) family which consists in a combination of very thin aluminium sheets and composite glass-fibre/epoxy-resin layers. This FML is widely used in the aeronautical sector because, compared to aluminium material, it provides a better structural strength and fatigue resistance, along with a better impact and corrosion resistance.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129947414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.118
T. Ata, D. Coker
{"title":"Investigation of Three-Dimensional Dynamic Delamination in Curved Unidirectional CFRP Laminates","authors":"T. Ata, D. Coker","doi":"10.23967/composites.2021.118","DOIUrl":"https://doi.org/10.23967/composites.2021.118","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121905130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.121
Pierre M. Daniel, Johannes Fr¨amby, Pere Maim´ı, Martin Fagerstr¨om
It is well known that the mechanical response of laminated composite materials is greatly affected by out-of-plane failures. The traditional numerical modelling of these interface cracks, where each ply is discretized separately, leads to an unbearable computational cost for large structures. The present work outlines a method for the efficient modelling of delamination initiation and propagation under dynamic loading conditions. The crack initiation is detected, in an unrefined state, by the mean of a Stress Recovery method for arbitrarily curved laminates [1]. Where necessary, the model is refined through an adaptive strategy to kinematically describe the interface discontinuity [2, 3]. The delamination propagation is determined by the Virtual Crack Closure Technique to which an energy dissipation mechanism has been added. The resulting model is efficient as it allows the use of large elements and therefore also a large stable time step in explicit analysis. It also demonstrates similar accuracy compared to the traditional cohesive approach.
{"title":"Efficient Modelling of Delamination Initiation and Propagation in Large Structures","authors":"Pierre M. Daniel, Johannes Fr¨amby, Pere Maim´ı, Martin Fagerstr¨om","doi":"10.23967/composites.2021.121","DOIUrl":"https://doi.org/10.23967/composites.2021.121","url":null,"abstract":"It is well known that the mechanical response of laminated composite materials is greatly affected by out-of-plane failures. The traditional numerical modelling of these interface cracks, where each ply is discretized separately, leads to an unbearable computational cost for large structures. The present work outlines a method for the efficient modelling of delamination initiation and propagation under dynamic loading conditions. The crack initiation is detected, in an unrefined state, by the mean of a Stress Recovery method for arbitrarily curved laminates [1]. Where necessary, the model is refined through an adaptive strategy to kinematically describe the interface discontinuity [2, 3]. The delamination propagation is determined by the Virtual Crack Closure Technique to which an energy dissipation mechanism has been added. The resulting model is efficient as it allows the use of large elements and therefore also a large stable time step in explicit analysis. It also demonstrates similar accuracy compared to the traditional cohesive approach.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123880603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.23967/composites.2021.116
I. Lopes, P. Camanho, F. Pires
The mechanical behaviour of unidirectional composites is usually modelled under the assumption of infinitesimal strains. Even though this assumption is valid for most applications involving composites based on thermoset polymers, it may become questionable when thermoplastics are employed in the composite matrix. An invariant-based constitutive model at finite strains has been developed taking into account visco-elastic and visco-plastic effects. It is based on the multiplicative decomposition of the deformation gradient and the definition of the isoclinic configuration [1] being the result of the extension of a small strain model [2] to a finite strain framework. It is implemented for a finite element solution and the numerical results are compared to available experimental data.
{"title":"Modelling the Finite Strain Behaviour of Unidirectional Composites: an Invariant-Based Model with Viscous Effects","authors":"I. Lopes, P. Camanho, F. Pires","doi":"10.23967/composites.2021.116","DOIUrl":"https://doi.org/10.23967/composites.2021.116","url":null,"abstract":"The mechanical behaviour of unidirectional composites is usually modelled under the assumption of infinitesimal strains. Even though this assumption is valid for most applications involving composites based on thermoset polymers, it may become questionable when thermoplastics are employed in the composite matrix. An invariant-based constitutive model at finite strains has been developed taking into account visco-elastic and visco-plastic effects. It is based on the multiplicative decomposition of the deformation gradient and the definition of the isoclinic configuration [1] being the result of the extension of a small strain model [2] to a finite strain framework. It is implemented for a finite element solution and the numerical results are compared to available experimental data.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126817879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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