Theoretical Determination of the Mechanical Response of Spun-bonded Nonwovens

Bais-Singh, Smita; Goswami, Bhuvenesh C.

doi:10.1080/00405009508631333

Cited by 41 publications

(26 citation statements)

References 10 publications

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“…The basic principles of this model are similar to the layer theory model we proposed in an earlier publication [ 4 ] . The nonwoven web is assumed to be made up of a number of layers of fibers such that all fibers in a layer are oriented in the same direction, as shown in Figure 2 [ 4 ] .…”

Section: Micromechanical Modelmentioning

confidence: 95%

“…In other words, the stiffness matrix of a material needs to be specified completely without ignoring any components. In the simple strain-based model called the &dquo;layer theory&dquo; [ 4 ] , the stiffness terms relating to transverse and shear stiffness of a layer as well as coupling coefficients between transverse and longitudinal strain of a layer are neglected due to their small magnitude. However, the constitutive model for defining the material behavior in a finite element model cannot neglect any stiffness terms a priori in order to be able to satisfy the force equilibrium and strain compatibility conditions at all times.…”

Section: Micromechanical Modelmentioning

confidence: 99%

“…The nonwoven web is assumed to be made up of a number of layers of fibers such that all fibers in a layer are oriented in the same direction, as shown in Figure 2 [ 4 ] . The web can consist of fibers oriented in various directions.…”

Section: Micromechanical Modelmentioning

confidence: 99%

See 2 more Smart Citations

Finite Element Modeling of the Nonuniform Deformation of Spun-Bonded Nonwovens

Bais-Singh

Biggers

Goswami

1998

Textile Research Journal

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Deformation of a spunbonded nonwoven fabric specimen is extremely nonuniform during a uniaxial tensile test. Complex stress/strain fields are generated in the specimen due to the effect of the jaws, the nonlinear nature of deformation, and the low shear stiffness of the fabric, causing "necking" to take place in the unrestricted region. A finite element model is presented to model the nonuniform deformation of the fabric. Nonuniform stress/strain fields developing in the fabric during a uniaxial test are modeled for the first time. Data from representative tests are reported for comparison to the results. obtained with the model. The model correctly predicts the variation of Poisson's ratio with longitudinal strains. Unlike previous studies, correct boundary conditions and force equilibrium conditions are incorporated in the model. The important effects of fiber buckling and material nonlinearity are discussed.Uniaxial tensile testing is the most commonly used method for characterizing the tensile deformation of a nonwoven fabric. In current practice, a state of uniform stress and strain is assumed in the entire fabric in order to interpret the data from such experiments. For a linear isotropic material, the elffect of the end constraints is expected to vanish away from the jaws. However, in complex fibrous structures such as some nonwovens, unlike the linear elastic materials, deformation is extremely nonuniform. In such structures, for example, the lateral contraction of the specimen does not become constant at some distance away from the jaws, but increases gradually towards the center of the specimen, forming a &dquo;neck.&dquo; The nonlinear stress-strain behavior of the constituent fibers, the significant shear effects existing in a conventional uniaxial test, and the extremely low stiffness of the fabrics under compressive strains are some factors believed to be responsible for this behavior. In this paper, we take all these factors into account to correctly model nonuniform deformation of a fabric. We present analytical and experimental evidence to demonstrate that the stress and strain fields developing in a nonwoven. specimen are not uniform, and we formulate a finite element model to simulate the nonuniform development of stresses and strains in a fabric.

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Section: Micromechanical Modelmentioning

confidence: 95%

Section: Micromechanical Modelmentioning

confidence: 99%

See 1 more Smart Citation

Finite Element Modeling of the Nonuniform Deformation of Spun-Bonded Nonwovens

Bais-Singh

Biggers

Goswami

1998

Textile Research Journal

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“…Cox (1952) presented the first micromechanical modeling approach based on a fiber orientation distribution. In the following decades, various improvements to the material modeling capability were suggested (Bais-Singh and Goswami, 1995;Narter et al, 1999;Kothari and Patel, 2001;Liao and Adanur, 1997;Rawal, 2006). The experiments by Jearanaisilawong (2008) and Chocron et al (2008) et al (2010) on chemically bonded nonwoven felts made from E-glass fibers provide extensive data about deformation and failure behavior.…”

Section: Introductionmentioning

confidence: 96%

A micromechanical model with strong discontinuities for failure in nonwovens at finite deformations

Raina

Linder

2015

International Journal of Solids and Structures

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a b s t r a c tThis paper presents a new methodology to model failure phenomena in nonwoven materials with a random network microstructure at finite deformations. The recently developed homogenization technique for nonwoven materials (Raina and Linder, 2014) is combined with an enhanced deformation gradient arising due to strong discontinuities within the bulk. This allows to capture the anisotropic and nonlinear material bulk response with propagating cracks in the failing nonwoven at finite strains. The homogenization technique averages the microscale one-dimensional linear response over an orientation space to yield an accurate macroscale nonlinear behavior. Fiber reorientation and straightening phenomena are incorporated in an orientation space to account for non-affine deformation in a phenomenological manner. The failure in the form of cracks is incorporated locally as displacement jumps, so-called strong discontinuities. The local nature of displacement jumps allows their static condensation from the global governing equations, resulting in a compact and computationally efficient formulation. The computation of an objective enhanced deformation gradient, at a material point where failure is detected, follows the well-known incorporation of constant and linear separation modes directly into the finite element. The orientation space is subjected to this enhanced deformation gradient to yield the corresponding Kirchhoff stress tensor and elasticity modulus. Based on a micromechanically computed fracture strength, the proposed methodology is verified in terms of quantitative comparisons of the simulation results with experimental data from the literature.

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“…While the significance of the effects of Poisson's ratios on fabric drape and other behaviors is well recognized, their values were mostly estimated, based on those for ordinary solid materials, for fabric modeling and simulations [14,15]. Although a few papers dealt with the theoretical prediction of Poisson's ratios for nonwovens [16,17], there has been little done analytically determining Poisson's ratios for woven fabrics based on the assumption of extensible yarns in fabrics, and discussing the influences of the mechanical properties of yarns and the geometrical parameters of fabrics on the Poisson's values. This paper tries to fill the need.…”

Section: Introductionmentioning

confidence: 99%

On the Poisson's ratios of a woven fabric

Sun

Pan

Postle

2005

Composite Structures

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Although it is undeniable that the Poisson's effect on the behavior of a woven fabric is crucial, there have been relatively few papers devoted to this subject. In this study, a mechanical model for a woven fabric made of extensible yarns is developed to calculate the fabric Poisson's ratios.Theoretical results are compared with the available experimental data. A thorough examination on the influences of various mechanical properties of yarns and structural parameters of fabrics on the Poisson's ratios of a woven fabric is given. The prediction of Poisson's ratios in this paper will enable more rigorous studies on such important issues of fabric bending and draping behaviors.

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Theoretical Determination of the Mechanical Response of Spun-bonded Nonwovens

Abstract: A new theory Is presented to predict the tensile behaviour of spun-bonded nonwoven fabrics from the knowledge of the stress-strain behaviour of its constituent fibers, their orientation angle distribution, the fabric's Poisson's ratio and their shear strains.

Cited by 41 publications

References 10 publications

Finite Element Modeling of the Nonuniform Deformation of Spun-Bonded Nonwovens

Finite Element Modeling of the Nonuniform Deformation of Spun-Bonded Nonwovens

A micromechanical model with strong discontinuities for failure in nonwovens at finite deformations

On the Poisson's ratios of a woven fabric

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