Author(s): Harun Bayraktar, David Ehrlich, George Scarlat, Michael McClain, Nikolay Timoshchuk, Chris Redman Presented At: SAMPE 2015 Publication Date: May 2015 Meso-scale analysis that lines up with ICCM paper on curved beam empirical testing (ASTM D6415); looks at 3D composite corner element testin and performance. Download |
Author(s): Harun Bayraktar, David Ehrlich, Jon Goering, Michael McClain Presented At: 20th International Conference on Composite Materials Copenhagen, 19-24th July 2015 Publication Date: 19-24 July 2015 Presentation on specific energy absorption (SEA) performance of 3D Woven composites, focusing on Finite lement Analysis (FEA) and application to automotive crash structures Download |
Author(s): Christopher Redman, Harun Bayraktar, Michael McClain Presented At: 2014 SAMPE Publication Date: 2014 3D vs. 2D ASTM D6415 comparison - placed beams with 90 degree bends in four point loading. Results demonstrated that certain types of 3D composite support more than two times the load of a quasi-isotropic 2D composite. Keywords: corner element, ASTM D6415, 3D composites. Download |
Author(s): Harun Bayraktar, Igor Tsukrov, Michael Giovinazzo, Jon Goering, Todd Gross, Monica Fruscello, Lars Martinsson Presented At: SAMPE 2012, Baltimore, MD Publication Date: May 2012 Three-dimensional woven composites that are becoming increasingly popular in aerospace applications have superior through-the-thickness strength, stiffness, and thermal conductivity compared to conventional 2D laminated composites. However, despite their advantages, many details regarding the mechanical behavior of 3D woven composites are not as well-known as they are for traditional laminated composites. Microcracking of carbon-epoxy composites during resin curing is one important example. The main goal of this study is to improve the understanding of cure-induced microcracking through the development of realistic numerical models validated with experimental data. Specifically, microcracking predictions of unit cell finite element models of two different fiber architectures are compared with results of micro-computed tomography scans of actual panels with the same fiber architectures. The curing process is simulated using thermal stress analysis and numerical predictions of the stress concentration areas correlate well with the observations of microcracking obtained by micro-computed tomography. Download |
Author(s): Mike McClain and Jonathan Goering Presented At: SAMPE 2012, Baltimore, MD Publication Date: May 2012 3D weaving is a manufacturing technique for producing near net shape fiber preforms. These preforms can be processed into composite components using liquid molding techniques such as resin transfer molding (RTM) or the vacuum assisted process (VAP®). One of the main advantages of 3D woven preforms is that the touch labor required to assemble them is minimal, leading to rapid and highly automated preform construction. This paper describes an application which uses 3D woven preforms as building blocks in a more complicated fiber preform assembly. Details of the construction of the individual 3D woven preforms, their assembly into larger preforms, and estimates of labor savings relative to conventional laminated construction are discussed. Download |
Author(s): Michael McClain and Jonathan Goering Presented At: Society of Manufacturing Engineers’ (SME) Composites Manufacturing 2012 Publication Date: March 2012 Three dimensional woven composite structures are slated to provide significant weight savings
on the next generation of engines for commercial aircraft. The inherent toughness of these
structures, the weight savings and the ability to weave near net shapes were key drivers in their
selection for these applications. This discussion will provide an overview of the 3D weaving process as well as a summary of recent work in the area of 3D composite and preform fabrication. On-going work currently
focuses on using the technology to fabricate beams and frames. Of particular interest is the
fabrication of sine wave beams that do not require the darting associated with prepreg type
structures. Download |
Author(s): Harun Bayraktar, Jon Goering, Monica Fruscello, Lars Martinsson, Michael Giovinazzo, Igor Tsukrov, Todd Gross Presented At: 52nd AIAA Structures, Structural Dynamics and Materials Conference, Denver, CO Publication Date: 2011 Despite their many advantages in performance, manufacturing, and cost, many details regarding the mechanical behavior of 3D woven composites are not as well known as they are for traditional laminated composites. Cure-induced microcracking that can occur in 3D woven composites with certain fiber architectures and resins is one important example. The main goal of this study was to develop experimentally validated realistic finite element models to better understand this phenomenon and predict microcracking. Another goal was to validate the use of micro-computed tomography (μCT) to detect microcracking within 3D woven composites. Our results show that μCT technology can be successfully used to detect microcracking and that microcracking is more prevalent in “orthogonal” fiber architectures with increased through-thickness reinforcement. Consistent with this, the numerical models for “ply-to-ply” architectures with little through-thickness reinforcement do not predict microcracking which was confirmed by μCT scans. Difficulties encountered in modeling orthogonal architectures and future work to overcome these are also discussed. (paper purchased as part of full conference proceedings) Download |
Author(s): Igor Tsukrov, Harun Bayraktar, Michael Giovinazzo, Jon Goering, Todd Gross, Monica Fruscello, Lars Martinsson Published In: International Journal of Fracture, Volume 172, Pages 209-216Publication Date: 2011 Realistic finite element models of 3D woven composites are constructed utilizing micro-scale numerical modeling to accurately represent the geometry of as-woven textile fabrics. The models are used to predict microcracking of carbon fiber / epoxy composites during resin curing. Numerical predictions of the stress concentration areas correlate well with the observations of microcracking obtained by micro-computed tomography. Download |
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