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Shankar Kalyanasundaram - One of the best experts on this subject based on the ideXlab platform.
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deformation Behaviour of steel srpp fibre metal laminate characterised by evolution of surface strains
Advances in aircraft and spacecraft science, 2016Co-Authors: Jae Nam, W.j. Cantwell, Adrian Lowe, Raj Das, Shankar KalyanasundaramAbstract:Climate changes brought on by human interventions have proved to be more devastating than predicted during the recent decades. Recognition of seriousness of the situation has led regulatory organisations to impose strict targets on allowable carbon dioxide emissions from automotive vehicles. As a possible solution, it has been proposed that Fibre Metal Laminate (FML) system is used to reduce the weight of future vehicles. To facilitate this investigation, FML based on steel and self-reinforced polypropylene was stamp formed into dome shapes under different blank holder forces (BHFs) at room temperature and its Forming Behaviour analysed. An open-die configuration was used in a hydraulic press so that a 3D photogrammetric measurement system (ARAMIS) could capture real-time surface strains. This paper presents findings on strain evolutions at different points along and at 45o to fibre directions of circular FML blank, through various stages of Forming. It was found initiation and rate of deformation varied with distance from the pole, that the mode of deformations range from biaxial stretching at the pole to drawing towards flange region, at decreasing magnitudes away from the pole in general. More uniform strain distribution was observed for the FML compared to that of plain steel and the most significant effects of BHF were its influence on Forming depth and level of strain reached before failure.
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Effect of Chemical Treatments on Flax Fibre Reinforced Polypropylene Composites on Tensile and Dome Forming Behaviour
International Journal of Molecular Sciences, 2015Co-Authors: Wentian Wang, Adrian Lowe, Shankar KalyanasundaramAbstract:Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid Forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid Forming of this class of material system
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effect of blank holder force on strain evolution of Forming of steel srpp fibre metal laminate
The 8th Australasian Congress on Applied Mechanics 2014 (ACAM 8), 2014Co-Authors: Jae Nam, W.j. Cantwell, Adrian Lowe, Raj Das, Shankar KalyanasundaramAbstract:Climate changes brought on by human interventions have proved to be more devastating than predicted during the recent decades. Recognition of seriousness of the situation has led regulatory organisations to impose strict targets on allowable carbon dioxide emissions from automotive vehicles. As a possible solution, it has been proposed that Fibre Metal Laminate (FML) system is used to reduce the weight of future vehicles. To facilitate this investigation, FML based on steel and self-reinforced polypropylene was stamp formed into dome shapes under different blank holder forces (BHFs) at room temperature and its Forming Behaviour analysed. An open-die configuration was used in a hydraulic press so that a 3D photogrammetric measurement system (ARAMIS) could capture real-time surface strains. This paper presents findings on strain evolutions at different points along and at 45 to fibre directions of circular FML blank, through various stages of Forming. It was found initiation and rate of deformation varied with distance from the pole, that the mode of deformations range from biaxial stretching at the pole to drawing towards flange region, at decreasing magnitudes away from the pole in general. More uniform strain distribution was observed for the FML compared to that of plain steel and the most significant effects of BHF were its influence on Forming depth and level of strain reached before failure.
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stamp Forming analysis of a fibre metal laminate system consisting of a glass fibre reinforced composite
Proc. 8th Australasian Congress on Applied Mechanics ACAM8, 2014Co-Authors: Shankar Kalyanasundaram, Sivakumar DharmalingamAbstract:In an effort to reduce greenhouse gas emissions from fuel combustion generated by the transportation sector, the use of lightweight materials such as composites is currently being intensively explored. The projected improvement in fuel-economy for passenger vehicles is 6-7% for every 10% of weight reduction. Fibre Metal Laminate (FML) systems are a class of composite materials comprised by alternating aluminium sheets and fibre reinforced composites. The resulting synergy of material Behaviour gives FML systems superior mechanical properties when compared with those of their individual constituent materials. FML systems based on thermoplastic composites have been shown to possess better fracture toughness, shorter processing times, good impact and localised blast resistance compared to metals. These structures have been successfully employed in the aerospace industry. However, the widespread use of these material systems is restricted by the current manufacturing processes required to create components. For the better utilisation of FML systems, it is necessary that the thermal properties of the materials be used in addition to conventional processing. This would involve the heating of the FML prior to Forming. However, a successful approach that includes both metal Forming processes and the composite Forming process is essential to maintain the high manufacturing volumes currently required for industry. It is likely that this approach would be similar to the stamp Forming process used in sheet metal manufacturing with an included pre-heat stage. In this work, results will be presented for FML systems consisting of aluminium/Glass fibre reinforced thermoplastic/aluminium configuration. A Design of Experiments (DOE) methodology was adopted to elucidate the effect of process parameters that included blank holder force, pre-heat temperature and feed rate on dome Forming studies. A real time strain measurement system was used to monitor the strain evolution during Forming. An open die configuration was adopted to facilitate the strain evolution during Forming. Three points of interest were chosen to study the different Forming modes exhibited at different locations in the FML system. The results indicate that the presence of the composite layer modify the Forming Behaviour of the FML system compared to Forming of monolithic aluminium alloy.
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numerical investigation of the effect of temperature on the formability of a thermoplastic fibre metal laminate
Proceedings: the 7th Australasian Congress on Applied Mechanics (ACAM 7) 9-12 December 2012 the University of Adelaide North Terrace Campus National C, 2012Co-Authors: Sivakumar Dharmalingam, Anthony Sexton, Sudharshan Venkatesan, Shankar KalyanasundaramAbstract:Numerical analysis of the stamp Forming of FML systems would provide a powerful tool for the optimisation of the process parameters and a fundamental understanding of the deformation Behaviour of this material system. This study uses the finite element analysis software, LS-DYNA, to simulate the effect of temperature on the stamp Forming of a FML based on a polypropylene based composite. This numerical model is validated through comparison with experiments conducted using a hemispherical punch and non-contact optical measurement system. The combination of real-time optical strain measurement and non-linear FEA to analyse and predict the Forming of this material is a significant advancement in the understanding of FML systems. A major conclusion derived from the FE simulations and experiments is that temperature is an important metric to the Forming Behaviour of the FML.
Heinz Palkowski - One of the best experts on this subject based on the ideXlab platform.
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mechanical properties and Forming Behaviour of laminated steel polymer sandwich systems with local inlays part 2 stretching and deep drawing
Composite Structures, 2017Co-Authors: Mohamed Harhash, Adele Carradò, Heinz PalkowskiAbstract:Abstract In part 1, a fundamental study on mechanical properties and deep drawing of a steel/polymer/steel sandwich (SMs) combination was accomplished investigating one type of reinforced SMs (R-SMs). In this part, the effect of reinforcements (REs) with different geometries, sizes, materials and locations on stretching and deep drawability is introduced. Additionally, the influence of reinforcing SMs with different mechanical properties and skin/core thicknesses is considered. Therefore, a deep drawable steel grade with thicknesses 0.49 mm and 0.24 mm was utilized. For the core polyolefin (PP-PE) foils with thicknesses of 0.3 mm and 0.6 mm were used. Substantial reduction of the deep drawability was found if the RE is located in the Forming region (close to the punch), however, only locally if located in the flange area. Inserting the RE in the flange has no remarkable effect on the drawing force but on the Forming potential represented by the cup height at failure. The stretching results show that increasing the RE size reduces the Forming potential. The RE creates a sharp interface with the neighbour core layer accelerating failure. A negligible effect of the RE geometry was found, however solid REs show reduced Forming limits compared to the mesh-like ones.
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mechanical properties and Forming Behaviour of laminated steel polymer sandwich systems with local inlays part 1
Composite Structures, 2014Co-Authors: Mohamed Harhash, Olga Sokolova, Adele Carradò, Heinz PalkowskiAbstract:Abstract Steel/polymer/steel sandwich materials (SMs) with varying core thickness were produced using the roll bonding technology. At constant skin thickness, the effect of the core thickness change on the mechanical properties, particularly their specific stiffness and strength, was investigated. Additionally, the SMs were locally reinforced with steel inlays to improve their Behaviour against dimension changes or the degradation of the core in case of local loading or joining. The effect of the reinforcement (RE) on the strain distribution under deep drawing conditions was studied. Strains were measured using photogrammetry. To take into account the influence of anisotropy in this sense, an essential anisotropy evaluation was carried out for the SMs to assess their Forming Behaviour. The results revealed an adequate agreement between the measured mechanical properties of SMs and the estimated values following the rule of mixtures. Up to a core volume fraction of approx. 0.37, the specific stiffness and strength values of the SMs are only slightly reduced compared to the monolithic steel material. The deformation analysis shows a significant influence of the inserted REs on the strain distribution and failure and consequently the position of cracking, occurring at the bottom/edge region in front of the RE.
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deep drawing properties of lightweight steel polymer steel sandwich composites
Archives of Civil and Mechanical Engineering, 2012Co-Authors: Olga Sokolova, Ma Kuh, Heinz PalkowskiAbstract:Abstract Due to the wide range of different properties – such as high strength, stiffness, high damping capacity, vibration resistance and the lightweight – metal/polymer/metal sandwich composites find their application as various body-parts in the automotive industry. Nevertheless the Forming potential of layered sandwiches under different loading is not well studied. In this research the formability of 316L/PP–PE/316L sandwich composites with different sample size and core thickness was studied for the deep drawing process using two flat punches of different size and shape. It could be stated that the Forming Behaviour of the three layered sandwiches is strongly influenced by the geometry of the punch and the core thickness. The results were analysed photogrammetrically and metallographically.
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metal polymer metal sandwiches with local metal reinforcements a study on formability by deep drawing and bending
Composite Structures, 2011Co-Authors: Olga Sokolova, Adele Carradò, Heinz PalkowskiAbstract:Abstract The formability of metal–polymer–metal sandwich composites with embedded different solid and mesh steel inlays was investigated with the aim to gain information about their Forming Behaviour by shaping, especially deep drawing and bending. Therefore the geometry and the size of the local inlays have been varied. The reduction in thickness of these composites was quantified by photogrammetry. As a result the formability of sandwich composites with solid steel inlays is lower compared to non-reinforced ones. Sandwiches with mesh inlays showed a slightly increased thinning compared to sandwiches with circular solid inlays. Both variations revealed good formability. The results will be used for future tailoring of sandwich structures with particularly demanded properties.
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press joining rolling process for hybrid systems
Key Engineering Materials, 2010Co-Authors: Adele Carradò, Olga Sokolova, Gerhard Ziegmann, Heinz PalkowskiAbstract:The press joining rolling process used for the production of metal/polymer/metal systems is introduced. In the first step three-layer sandwich sheet, 316L/polypropylene- polyethylene/316L (316L/PP-PE/316L) with and without local reinforcement, were processed by roll bonding at approx. 250°C of two steel sheets with a pre-rolled PP-PE - core sheet. Mechanical and Forming Behaviour of the parts had been investigated by tensile, bending and deep drawing tests. It could be shown that for moderate drawing depths deep drawing Behaviour is close to the one of the mono-material.
Frank Henning - One of the best experts on this subject based on the ideXlab platform.
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nonlinear hyperviscoelastic modelling of intra ply deformation Behaviour in finite element Forming simulation of continuously fibre reinforced thermoplastics
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Dominik Dorr, Frank Henning, Luise KärgerAbstract:Abstract A nonlinear hyperviscoelastic approach for modelling rate-dependent intra-ply deformation Behaviour in FE Forming simulation of continuously fibre-reinforced polymers is presented. This approach follows either a Voigt-Kelvin approach or a generalized Maxwell approach based on a multiplicative decomposition of the deformation gradient. The constitutive equations are implemented in a “Discrete Kirchhoff Triangle” shell formulation within an Abaqus user-element, including a physical decoupling of membrane and bending Behaviour. The approach is parameterized for a thermoplastic UD-tape (PA6-CF) at different strain-rates and temperatures above the crystallization temperature and applied to iso-thermal Forming simulation. Parametrization results reveal that only the generalized Maxwell approach represents the whole material characteristic. Moreover, a difference in Forming Behaviour is observed for the investigated temperatures and constitutive equations. The difference, however, is small, which reveals that iso-thermal Forming simulation following a Voigt-Kelvin approach is suitable for prediction of Forming Behaviour within a suitable process window, where isothermal conditions are assumable.
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A macroscopic approach to simulate the Forming Behaviour of stitched unidirectional non-crimp fabrics (UD-NCF)
Composites Part A: Applied Science and Manufacturing, 2017Co-Authors: F. J. Schirmaier, David Dorr, Frank Henning, Luise KärgerAbstract:Thin composite shell structures manufactured from stitched unidirectional non-crimp fabrics (UD-NCF) in a liquid composite moulding process provide high lightweight design capabilities. For complex geometries, the Forming process of the textile pre-products is challenging and requires intensive investigations to avoid defects like macroscopic wrinkling or fibre gapping. In contrast to biaxial engineering fabrics, UD-NCF has been investigated only sparsely in terms of its Forming Behaviour, both experimentally and numerically. To close this gap, a macroscopic Forming simulation model for UD-NCF is proposed in this work, including a new non-orthogonal and linear strain measure for large strains and the corresponding nominal stress measure. To parameterize the constitutive laws and to investigate the multiaxial deformation Behaviour of UD-NCF, supplementary off-axis-tension tests with optical strain measurement are performed in this work. The new Forming simulation model is validated via Forming simulation of a hemisphere test and of a preForming process of an automotive component.
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characterisation of the draping Behaviour of unidirectional non crimp fabrics ud ncf
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: F. J. Schirmaier, Luise Kärger, Frank Henning, Kay Andre WeidenmannAbstract:Abstract Thin composites shell structures manufactured from stitched unidirectional non-crimp fabrics (UD-NCF) in a liquid composite moulding process provides high lightweight design capabilities. However, draping Behaviour of UD-NCF has been investigated only sparsely, in contrast to research on woven fabrics or biaxial non-crimp fabrics. Hence, this contribution focuses on fundamental investigations of the draping Behaviour of UD-NCF. Within this investigation picture frame tests and uniaxial bias extension tests are performed to examine the in-plane shear Behaviour of UD-NCF. Furthermore, a new method is presented to examine ambivalent tensile Behaviour of UD-NCF transverse to the carbon fibre roving orientation. In particular, the influence of thin glass fibres on transverse tensile Behaviour of UF-NCFs is investigated using a new clamping mechanism in tensile testing. Finally, hemisphere tests are performed to observe the Forming Behaviour of UD-NCF in a realistic Forming process and to evaluate the proposed material characterisation methods regarding its suitability for UD-NCFs.
Luise Kärger - One of the best experts on this subject based on the ideXlab platform.
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nonlinear hyperviscoelastic modelling of intra ply deformation Behaviour in finite element Forming simulation of continuously fibre reinforced thermoplastics
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Dominik Dorr, Frank Henning, Luise KärgerAbstract:Abstract A nonlinear hyperviscoelastic approach for modelling rate-dependent intra-ply deformation Behaviour in FE Forming simulation of continuously fibre-reinforced polymers is presented. This approach follows either a Voigt-Kelvin approach or a generalized Maxwell approach based on a multiplicative decomposition of the deformation gradient. The constitutive equations are implemented in a “Discrete Kirchhoff Triangle” shell formulation within an Abaqus user-element, including a physical decoupling of membrane and bending Behaviour. The approach is parameterized for a thermoplastic UD-tape (PA6-CF) at different strain-rates and temperatures above the crystallization temperature and applied to iso-thermal Forming simulation. Parametrization results reveal that only the generalized Maxwell approach represents the whole material characteristic. Moreover, a difference in Forming Behaviour is observed for the investigated temperatures and constitutive equations. The difference, however, is small, which reveals that iso-thermal Forming simulation following a Voigt-Kelvin approach is suitable for prediction of Forming Behaviour within a suitable process window, where isothermal conditions are assumable.
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A macroscopic approach to simulate the Forming Behaviour of stitched unidirectional non-crimp fabrics (UD-NCF)
Composites Part A: Applied Science and Manufacturing, 2017Co-Authors: F. J. Schirmaier, David Dorr, Frank Henning, Luise KärgerAbstract:Thin composite shell structures manufactured from stitched unidirectional non-crimp fabrics (UD-NCF) in a liquid composite moulding process provide high lightweight design capabilities. For complex geometries, the Forming process of the textile pre-products is challenging and requires intensive investigations to avoid defects like macroscopic wrinkling or fibre gapping. In contrast to biaxial engineering fabrics, UD-NCF has been investigated only sparsely in terms of its Forming Behaviour, both experimentally and numerically. To close this gap, a macroscopic Forming simulation model for UD-NCF is proposed in this work, including a new non-orthogonal and linear strain measure for large strains and the corresponding nominal stress measure. To parameterize the constitutive laws and to investigate the multiaxial deformation Behaviour of UD-NCF, supplementary off-axis-tension tests with optical strain measurement are performed in this work. The new Forming simulation model is validated via Forming simulation of a hemisphere test and of a preForming process of an automotive component.
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characterisation of the draping Behaviour of unidirectional non crimp fabrics ud ncf
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: F. J. Schirmaier, Luise Kärger, Frank Henning, Kay Andre WeidenmannAbstract:Abstract Thin composites shell structures manufactured from stitched unidirectional non-crimp fabrics (UD-NCF) in a liquid composite moulding process provides high lightweight design capabilities. However, draping Behaviour of UD-NCF has been investigated only sparsely, in contrast to research on woven fabrics or biaxial non-crimp fabrics. Hence, this contribution focuses on fundamental investigations of the draping Behaviour of UD-NCF. Within this investigation picture frame tests and uniaxial bias extension tests are performed to examine the in-plane shear Behaviour of UD-NCF. Furthermore, a new method is presented to examine ambivalent tensile Behaviour of UD-NCF transverse to the carbon fibre roving orientation. In particular, the influence of thin glass fibres on transverse tensile Behaviour of UF-NCFs is investigated using a new clamping mechanism in tensile testing. Finally, hemisphere tests are performed to observe the Forming Behaviour of UD-NCF in a realistic Forming process and to evaluate the proposed material characterisation methods regarding its suitability for UD-NCFs.
Olga Sokolova - One of the best experts on this subject based on the ideXlab platform.
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mechanical properties and Forming Behaviour of laminated steel polymer sandwich systems with local inlays part 1
Composite Structures, 2014Co-Authors: Mohamed Harhash, Olga Sokolova, Adele Carradò, Heinz PalkowskiAbstract:Abstract Steel/polymer/steel sandwich materials (SMs) with varying core thickness were produced using the roll bonding technology. At constant skin thickness, the effect of the core thickness change on the mechanical properties, particularly their specific stiffness and strength, was investigated. Additionally, the SMs were locally reinforced with steel inlays to improve their Behaviour against dimension changes or the degradation of the core in case of local loading or joining. The effect of the reinforcement (RE) on the strain distribution under deep drawing conditions was studied. Strains were measured using photogrammetry. To take into account the influence of anisotropy in this sense, an essential anisotropy evaluation was carried out for the SMs to assess their Forming Behaviour. The results revealed an adequate agreement between the measured mechanical properties of SMs and the estimated values following the rule of mixtures. Up to a core volume fraction of approx. 0.37, the specific stiffness and strength values of the SMs are only slightly reduced compared to the monolithic steel material. The deformation analysis shows a significant influence of the inserted REs on the strain distribution and failure and consequently the position of cracking, occurring at the bottom/edge region in front of the RE.
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deep drawing properties of lightweight steel polymer steel sandwich composites
Archives of Civil and Mechanical Engineering, 2012Co-Authors: Olga Sokolova, Ma Kuh, Heinz PalkowskiAbstract:Abstract Due to the wide range of different properties – such as high strength, stiffness, high damping capacity, vibration resistance and the lightweight – metal/polymer/metal sandwich composites find their application as various body-parts in the automotive industry. Nevertheless the Forming potential of layered sandwiches under different loading is not well studied. In this research the formability of 316L/PP–PE/316L sandwich composites with different sample size and core thickness was studied for the deep drawing process using two flat punches of different size and shape. It could be stated that the Forming Behaviour of the three layered sandwiches is strongly influenced by the geometry of the punch and the core thickness. The results were analysed photogrammetrically and metallographically.
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metal polymer metal sandwiches with local metal reinforcements a study on formability by deep drawing and bending
Composite Structures, 2011Co-Authors: Olga Sokolova, Adele Carradò, Heinz PalkowskiAbstract:Abstract The formability of metal–polymer–metal sandwich composites with embedded different solid and mesh steel inlays was investigated with the aim to gain information about their Forming Behaviour by shaping, especially deep drawing and bending. Therefore the geometry and the size of the local inlays have been varied. The reduction in thickness of these composites was quantified by photogrammetry. As a result the formability of sandwich composites with solid steel inlays is lower compared to non-reinforced ones. Sandwiches with mesh inlays showed a slightly increased thinning compared to sandwiches with circular solid inlays. Both variations revealed good formability. The results will be used for future tailoring of sandwich structures with particularly demanded properties.
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press joining rolling process for hybrid systems
Key Engineering Materials, 2010Co-Authors: Adele Carradò, Olga Sokolova, Gerhard Ziegmann, Heinz PalkowskiAbstract:The press joining rolling process used for the production of metal/polymer/metal systems is introduced. In the first step three-layer sandwich sheet, 316L/polypropylene- polyethylene/316L (316L/PP-PE/316L) with and without local reinforcement, were processed by roll bonding at approx. 250°C of two steel sheets with a pre-rolled PP-PE - core sheet. Mechanical and Forming Behaviour of the parts had been investigated by tensile, bending and deep drawing tests. It could be shown that for moderate drawing depths deep drawing Behaviour is close to the one of the mono-material.