Numerical Modelling and Material Characterisation of Nonwovens
Nonwovens are polymer-based engineered textiles with a random microstructure. They require a numerical model to predict their performance and and make them more cost and time efficient.
In contrast to composites and woven fabrics, nonwoven materials have a unique web structure which is composed of randomly oriented polymer fibres. These fabrics have a wide range of applications including filtration, construction, automotive, medical and hygiene industries.
This project aims to develop a novel approach to simulate behaviour of nonwovens and their complex microstructure as a tool to study the relationship between mechanical properties of thermally bonded nonwovens and their structures. The procedure to determine this relationship begins with obtaining the orientation distribution function (ODF) that quantifies randomness of the microstructure. Then, the direction-dependent mechanical response of these materials are computed based on the ODF of fibres. Additionally, the effect of deformation on the anisotropic parameters is considered based on several experimental case studies, to check the validity of these parameters for large deformations.
The model developed as part of this project will enable advanced design procedures of nonwoven fabrics that are capable of predicting their mechanical performance.
Several research techniques were used in this project combining experimental and numerical tools including:
- Nonlinear Finite Element Analysis (MSC.Marc)
- Digital Image Processing (MATLAB)
- Image/volume acquisition with X-Ray micro CT and SEM
- Micro tensile testing system for testing single fibre mechanical performance
The numerical models developed in this research are effective in predicting the real deformation characteristics of thermally bonded nonwovens, verified with experiments and ready to use for applications in industry and academia. They can be built into any commercial finite element software package capable of implementing orthotropic plasticity procedures such as Hill’s orthotropic yield criterion. This is required to predict the response of various nonwoven materials under arbitrary loading conditions. These numerical models are parametric and scalable based on the manufacturing parameters which will lead to reduction of design time and costs for nonwovens.
Dr Emrah Demirci - Senior Lecturer in Mechanics of Advanced Materials
"This is an outstanding research in collaboration with several nonwoven companies which are members of The Nonwovens Institute, USA. It is really exciting to contribute to the world leading research in nonwovens field."