Finite element analysis of 2-D tubular braided composite based on geometrical models to study mechanical performances

Tubular Braided Composites (TBC) have a higher strength to weight ratio than conventional materials and better mechanical properties compared to laminated composite materials. The optimization of the TBC and the introduction of new applications requires a comprehensive understanding of TBC’s behavior. One efficient way to study the behavior of TBC is using Finite Element Modeling (FEM). This paper will introduce a method for generating geometrical models with different patterns and variables. Micro Computed-Tomography (μCT) is also used for generating an actual 3-D model of a TBC. The geometrical model and the μCT models are visually compared. The geometrical model is inputted into the FEM software package and is studied in different conditions. Finally, the result of FEM is compared against experimental and analytical results.Natural Sciences and Engineering Research Council (NSERC) Canada RGPIN- 2018-05899. CMC Microsystems provided the software used in this study

Experimental evaluation of carbon fibre, fibreglass and aramid tubular braided composites under combined tension-torsion loading

Braided composites are a class of composite materials that feature an inter-woven structure that improves structural stability and damage tolerance. Presently, braided composites under tension and torsion loading have been studied individually. Mechanical behaviour of braided composites under combined tension–torsion loading is common and therefore requires investigation. In this study, mechanical properties of carbon fibre, fibreglass and aramid 2D tubular braided composites (TBCs) were assessed and compared under coupled tension–torsion loading. The plane stress theory investigated the failure mechanism of braids. A contact-free three-dimensional digital image correlation (3D DIC) technique was used to derive detailed and continuous strain maps and understand the buckling behaviour of TBCs.Natural Sciences and Engineering Research Council (NSERC) Canada RGPIN-2018-0589

Fiber identification of braided composites using micro-computed tomography

Braided composites contain interwoven fibers that are embedded in a matrix material. Advanced measurement methods are required to accurately measure and characterize braided composites due to their interwoven composition. Micro-computed tomography (μCT) is an X-ray based measurement method that allows for the internal structure of objects to be examined. High-resolution μCT of braided composites allows for their internal geometry to be accurately measured. Braid samples were measured with a voxel size of 1.0 μm3, which resulted in a field of view of 4.904 x 4.904 x 3.064 mm3. With this field of view, individual fibers within the braid yarns could be identified and measured. The scientific visualization software package Avizo and the XFiber extension was used to identify and measure braid yarn fibers from the collected μCT measurements. Fiber properties such as orientation angles (ϕ and θ), curved fiber length, tortuosity, and fiber diameter were obtained. Additionally, finite element mesh geometries of the braid yarns within a braided structure were created. The presented methodology provides a roadmap for the accurate modeling of braided composite unit cell geometries using high-resolution μCT data.Natural Sciences and Engineering Research Council (NSERC) Canada RGPIN- 2018-05899. CMC Microsystems provided the software used in this study

Continuous Fiber Polymer Composites for Thermal Applications

Paper presented at 2018 Canadian Society of Mechanical Engineers International Congress, 27-30 May 2018.This paper presents an analytical investigation into the effective thermal conductivity of 3D printed continuous fibre polymer composites (CFPCs) using rule of mixture micro-structural analysis. Two fused deposition modelling techniques were utilized using a off-the-shelf printer and a low-cost modified printer. Results demonstrate significant improvement in the effective thermal conductivity of the composite compared to the base polymer. One samples was experimentally tested to examine the veracity of the model predictions

A Comparative Study on the Electromechanical Properties of 3D-Printed Rigid and Flexible Continuous Wire Polymer Composites for Structural Health Monitoring

In this study, the electromechanical properties of two different three-dimensional (3D) printed continuous wire polymer composites (CWPC) were characterized and compared. The two composite materials were copper wire polylactic acid (PLA) composite (rigid material) and copper wire polyurethane (PU) composite (flexible material). The electromechanical measurements were based on piezoresistive properties of the sensor at which the mechanical strain and the electrical resistance were correlated under a uniaxial loading condition. Both types of materials exhibited a direct linear relationship between the two quantities, indicating the ability of CWPC to be used for strain sensing applications. The gauge factor (GF) sensitivity was compared for the two types of materials. It was found that there is no statistical significance difference between the GF of PLA CWPC (1.36 ± 0.14) and PU CWPC (1.29 ± 0.07)); therefore, the sensing property depends mainly on the wire integrated into the 3D-printed structure rather than the matrix. Thus, different matrices can be used to fit different applications. An analytical model for GF showed agreement with the experimental results for both materials. PU CWPC showed significant improvement in both Young’s modulus (E) and ultimate tensile strength (UTS) (210.5 % and 31.86 %, respectively), compared with pure PU, while the change in Poisson’s ratio (ν) was insignificant. Young’s modulus of PLA CWPC was significantly increased by 80.3 % compared with PLA, while UTS and ν did not significantly change. The experimental mechanical properties showed good agreement with data from the analytical models. The outcome of this study focused on the manufacturing of 3D-printed functionalized structure for strain sensing applications with improved mechanical properties. The wide range of attained strain allowed their use in different applications based on the range of strain needed, such as rigid sports equipment and flexible wearable sensors.Natural Sciences and Engineering Research Council Canada (NSERC) RGPIN- 2018-0589