scholarly journals A novel discrete method of shear angle measurement for in-plane shear properties of thermoset prepreg using a point-tracking algorithm

2018 ◽  
Vol 53 (14) ◽  
pp. 2001-2013 ◽  
Author(s):  
Corentin Pasco ◽  
Muhammad Khan ◽  
Kenneth Kendall
Keyword(s):  
High Volume ◽  
Angle Measurement ◽  
Shear Angle ◽  
Tracking Algorithm ◽  
Image Correlation ◽  
Plane Shear ◽  
Shear Properties ◽  
Discrete Method ◽  
Point Tracking ◽  
Bias Extension

Determining accurate in-plane shear properties of dry and prepreg fabrics is dependent upon the correct measurement of actual shear angle values. This paper presents a novel discrete method of shear angle measurement for in-plane shear properties of thermoset prepreg using a point-tracking algorithm. Two different reinforcement forms of woven and unidirectional with the same rapid-cure resin system are used in this study. In-plane shear tests of picture-frame and bias-extension are employed to evaluate the new discrete method under conditions representative of high-volume manufacturing, i.e. fast deformation rate and elevated temperature. This study demonstrates that the proposed discrete method is capable of measuring the shear angle correctly until large shear deformation, unlike traditional methods such as digital image correlation and the pin-jointed network approach. Furthermore, the normalised shear force data presents a better correlation of the two tests based on the actual shear angle measurement obtained from this novel discrete method.

scholarly journals The influence of yarn fineness and number of yarn layers on in-plane shear properties of 3-D woven fabric

2020 ◽  
Vol 29 ◽  
pp. 2633366X1989792
Author(s):  
Liuxiang Guan ◽  
Jialu Li ◽  
Ya’nan Jiao
Keyword(s):  
Image Correlation ◽  
Woven Fabric ◽  
Weft Yarn ◽  
Warp Yarn ◽  
Plane Shear ◽  
Shear Properties ◽  
Bias Extension Test ◽  
Application Potential ◽  
Large Application ◽  
Bias Extension

The 3-D layer-to-layer angle-interlock woven fabric (LLAIWF) has good deformability on a complicated contour, which offers them a large application potential in the field of aerospace. This article mainly focuses on the influence of yarn fineness and number of yarn layers on in-plane shear properties of 3-D LLAIWF during bias extension. Two methods of varying the thickness of 3-D LLAIWF were designed: changing yarn fineness and changing the number of yarn layers. The deformation mechanism of LLAIWF in bias-extension test was analyzed. The effects of two methods on in-plane shear deformation were compared and analyzed. In addition to the data processing on the experimental curve, digital image correlation analysis was conducted on the test photographs, from which shear angles in different area shear angle were measured. The mesostructure of fabric during the bias-extension test was observed. The effect of decreasing yarn layers on the mesostructure of fabric was observed by cutting fabric. The results demonstrated that the yarn fineness and the number of yarn layers play a key role in the in-plane shear properties of 3-D LLAIWF. In addition, the changing of fabric thickness causes that the deformation is asymmetrical. The effect of warp yarn fineness is similar to that of weft yarn fineness during the bias-extension test. Reducing the internal yarns of the fabric created a gap, where the yarns were reduced. This gap will affect the deformability of the fabric.

Experimental and finite element analysis of in-plane shear properties of a carbon non-crimp fabrics at macroscopic scale

2017 ◽  
Vol 52 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Samir Deghboudj ◽  
Wafia Boukhedena ◽  
Hamid Satha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Model ◽  
Macroscopic Scale ◽  
Element Analysis ◽  
Plane Shear ◽  
Shear Properties ◽  
Bias Extension Test ◽  
Bias Extension ◽  
Composite Reinforcement

Shear deformation of composite reinforcement is the most significant and important mechanism of material characterization. So, in-plane shear properties of composite reinforcement are important parameters for determining application and use of this category of materials. The bias extension test is frequently employed to investigate the in-plane shear behavior of composites fabrics with a length equal to or greater than twice its width. In the first part of this work, bias extension tests on non-crimp fabrics have been conducted. Force and displacement were measured and registered. From obtained data, shear angles and normalized shear forces were theoretically determined. The second part was a finite element analysis of the same test based on hypo elastic model at macroscopic scale. The software ABAQUS/Explicit was used to carry out the finite element analysis in the work.

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