Parametric 3D modelling of nonwovens for mechanical and filtration propertie

Emrah Demirci (1256556)

Emrah Sozumert (7206080)

Martin J. Lehmann (7209368)

Memis Acar (1248636)

Vadim Silberschmidt (1248129)

English

Loughborough University Institutional Repository

1 Parametric 3D Modelling of Nonwovens for Mechanical and Filtration Properties  Emrah Sozumert1, Emrah Demirci1, Martin J. Lehmann2 ,  Memis Acar1, V. Vadim Silberschmidt1  1Wolfson School of Mechanical, Electrical and Manufacturing Engineering,  Loughborough University, Leicestershire, UK 2Simulation Filter Elements, MANN+HUMMEL GmbH,  Ludwigsburg, Germany  2 Motivation **http://www.nonwovens-industry.com/ *a2zbabybabydiapers.wordpress.com What does happen to nonwovens under tension and compression?  Does microstructure change? Does this affect mechanical, filtration and absorption properties? 3 Outline   Motivation  Objectives  Material and microstructure  Experiments  Tensile Performance   Out-of-plane Loading  A New Parametric 3D Computational Model  Flow Simulations  Summary and conclusions  i. To predict tensile, compression and filtration performance of nonwovens with computational models.  ii. To develop a new 3D parametric model to simulate compression of nonwovens and its effects on flow properties.  iii. To optimize available nonwovens by means of this new parametric model to enhance filtration and absorption performances.   4 Figure 1: Thermally bonded nonwovens Objectives Material and Microstructure 5 200µm  Bond point Fiber curvature Random orientation Fiber-to-fiber interactions Deep-groved fiber cross-section  Highly complicated materials due to material and microstructural properties Experiments 6 Test Instrument Outcome Scanning electron microscopy (SEM) Carl Zeiss, Leo, 1530VP FEGSEM Fabric characteristics  (bond pattern, shape…etc.) X-ray micro computed tomography (CT) XTEK XT-H 160Xi 3D image, ODF, bond pattern, shape and dimensions…etc. Fiber tensile tests Instron Micro Tester 5848 Elastic properties and rate-dependent flow curve Creep tests Instron Micro Tester 5848 Viscous properties Relaxation tests Instron Micro Tester 5848 Viscous properties Fabric tensile tests Hounsfield Benchtop Tester Mechanical response Experiments- Fiber Orientation Distribution  7 Fiber Orientation Distribution:  Grey-scale 2D images using a Hough-transform-based image processing algorithm (Demirci, 2011) Experiments - Single Fiber Tests 8  Individual fibers extracted from nonwovens and tested under a tensile tester with a ±5N load cell   Fibers exhibit highly time-dependent material behaviour.  Tensile tests with various strain rates  Relaxation tests Tensile Performance - Deformation and Damage Mechanisms 9  Discontinuous models   Continuous models  Out-of-plane Loading - a Falling Ball 10 New Parametric 3D Computational Model 11 50 gsm through air bonded nonwoven model TD Top view  Modelling of nonwoven network using fiber deposition and FE methods.   Multiple fiber types can be generated in the same model (For instance, main and binder fibers) 12 New Parametric 3D Computational Model-Capabilities Short Fibers Continuous  Fibers Various fiber cross-sections: rectangular hollow, round, trilobal, 4DG, etc 13 Flow Simulations – a Case Study  Star CCM+  Laminar air flow   No heat transfer, only continuity equations  8-10 millions cells  (Polyhedral,  tetrahedral elements)  Inlet velocities:  0.1, 0.25, 0.5, 1.0 m/s  No-slip on fibers  A through-air bonded nonwoven (90gsm, PP/PE 60:40) *SEM images  ODF  Nonwoven Model Pout =0 Vin 14 Flow Simulations – a Case Study  A section in the middle along the flow direction  A line of probes marked for calculations  Nonwoven network was compressed 50% in FE software and flow simulations were repeated. 15 Flow Simulations – Pressure Drop Vin , Pin Vout , Pout Vin , Pin Vout , Pout inlet inlet outlet outlet Zero Compression 50% Compression Pressure Drop without/with Compression Air Permeability (Darcy Law) Pressure Drop (Pa) Velocity (m/s) No Compression %50 Compression 0.1 1.64 2.12 0.25 4.23 5.50 0.5 9.09 11.78 1 20.86 26.69 Permeability Velocity  (m/s)  No Compression %50 Compression 0.1 2.17728E-09 8.40586E-10 0.25 2.11155E-09 8.11804E-10 0.5 1.96376E-09 7.57353E-10 1 1.71123E-09 6.68731E-10 Summary and Conclusions 16   A material characterization process in micro and macro scales is necessary to obtain material and geometric properties of nonwovens.    Tensile performance of nonwovens strongly depends on material properties of fibers and their orientation distributions (ODF’s).   Two dimensional continuous and discontinuous FE models, in which ODF was incorporated into, were presented. Their uses in simulating deformation, damage and out-of-plane loading were shown with sample cases.    A new parametric 3D finite-element model with fiber curvature and fiber-to fiber interactions was introduced.    Based on the new parametric model, flow simulations on an uncompressed and 50% compressed nonwoven were conducted. Pressure drop and permeability calculated.   By compressing nonwovens, a significant increase in pressure drop and a decrease in air permeability were observed.   17 Future Work – Compression of Nonwoven due to Fluid Flow h0 h1 h0  > h1 Coupling of Structural Analysis with Computational Fluid Dynamics At initial state At deformed state Acknowledgement 18 We greatly acknowledge support by:  - the Nonwoven Institute North Carolina State University, Raleigh, USA  - Wolfson School of Mechanical and Manufacturing Engineering  - MANN+HUMMEL GmbH,  Ludwigsburg, Germany  - Reicofil GmbH & Co, Germany      

Parametric 3D modelling of nonwovens for mechanical and filtration properties

https://repository.lboro.ac.uk/articles/Parametric_3D_modelling_of_nonwovens_for_mechanical_and_filtration_properties/9554540/files/17186324.pdf

Parametric 3D modelling of nonwovens for mechanical and filtration properties

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