Simulation of wrinkling during textile composite reinforcement forming. Influence of tensile, in-plane shear and bending stiffnesses

Abstract

Wrinkling is one of the most common flaws that occur during textile composite reinforcement forming processes. These wrinkles are frequent because of the possible relative motion of fibres making up the reinforcement, leading to a very weak textile bending stiffness. It is necessary to simulate their onset but also their growth and their shape in order to verify that they don't extend to the useful part of the preform. In this paper the simulation of textile composite reinforcement forming and wrinkling is based on a simplified form of virtual internal work defined according to tensions, in-plane shear and bending moments on a unit woven cell. The role of the three rigidities (tensile, in-plane shear and bending) in wrinkling simulations is analysed. If in-plane shear stiffness plays a main role for onset of wrinkles in double-curved shape forming, there is no direct relation between shear angle and wrinkling. Wrinkling is a global phenomenon depending on all strains and stiffnesses and on boundary conditions. The bending stiffness mainly determines the shape of the wrinkles and it is not possible to perform a wrinkle simulation using a membrane approach.

Experimental preforming of highly double curved shapes with a case corner using an interlock reinforcement

“…These non-useful zones are cut after the process. Consequently, these wrinkles have no consequences on the quality of the performs, but, these results confirm first the influence of the tension in yarns, due to the blank-holder pressure, on the presence of wrinkle and second the necessity to apply some load to obtain a preform without default [13].…”

“…Numerical simulations have already been extensively used to investigate the viability of fabric forming by optimization of process control parameters, material selection and tool design to avoid production of costly prototypes. Some of these simulations describe the evolution of the dry reinforcement behaviour by mechanical approach [10][11][12][13]. These numerical works must be validated, compared and complemented by experimental results.…”

Towards comprehensive characterisation and modelling of the forming and wrinkling mechanics of engineering fabrics

“…In this investigation it will also be employed to identify both the in-plane bending stiffness (D'Agostino et al, 2015;Dell'Isola and Steigmann, 2014;Ferretti et al, 2014;Giorgio et al, 2016;Harrison, 2016;Scerrato et al, 2016;Turco et al, 2016) and the torsional stiffness of the sheared fabric (Lomov and Verpoest, 2006;Steigmann and Dell'Isola, 2015) by monitoring the sample kinematics, including the shear angle at the centre of the specimen (D'Agostino et al, 2015;Ferretti et al, 2014;Harrison, 2016) and the out-of-plane wrinkling behaviour (Arnold et al, 2016;Boisse et al, 2011;Cherouat and Billoët, 2001;Dangora et al, 2015;Harrison, 2016;ten Thije and Akkerman, 2009;Thompson et al, 2016).…”

“…glass and carbon) is an important topic due to the role of engineering fabrics in manufacturing advanced composite parts (Long, 2005;Boisse, 2011). This investigation demonstrates an approach to characterising their mechanical forming properties using a combination of experimental testing and inverse modelling.…”

Mechanical characterisation of flax-based woven fabrics and in situ measurements of tow tensile strain during the shape forming

“…Uniaxial and biaxial tensile behaviours of the studied flax-based woven fabric can also be used as input data for the sheet forming simulation codes [56][57][58] which could be used in an iterative loop to design and optimise the architecture of new reinforcement material that could be used to form complex shape without defects.…”