Woven preforms

For nosetip materials 3-directional-reinforced (3D) carbon preforms are formed using small cell sizes for uniform ablation and small pore size. Figure 5 shows typical unit cell dimensions for two of the most common 3D nosetip materials. Carbon-carbon woven preforms have been made with a variety of cell dimensions for different appHcations (27—33). Fibers common to these composites include rayon, polyacrylonitrile, and pitch precursor carbon fibers. Strength of these fibers ranges from 1 to 5 GPa (145,000—725,000 psi) and modulus ranges from 300 to 800 GPa. 

Sol-gel filament winding of a woven preform (reproduced by permission of Chapman Hall)56. 

Non woven preformed Nonwoven, non-preformed Membranes Fixed... 

Yet, to succeed with this mission, textile researchers on one side and textile manufacturers interested in producing 3D woven preforms for composites on the other should conjointly address several serious challenges and remove many technical and industrial hurdles that have been identified and discussed in this chapter. 

Bogdanovich, A.E., 2007. Advancements in manufacturing and applications of 3-D woven preforms and composites. In CD-ROM Proceedings of the 16th International Conference on Composite Materials (ICCM-16), Kyoto, Japan, July 8-13, 2007. 

Bogdanovich, A.E., Wigent III, D.E., Whitney, T.J., 2003. Fabrication of 3-D woven preforms and composites with integrated fiber optic sensors. SAMPE J. 39 (4), 6-15. 

Quinn, J.P., Hill, B.J., McDhagger, R., 2001. An integrated design system for the manufacture and analysis of 3-D woven preforms. Compos. Part A 32, 911-914. 

Quinn, J., Mcllhagger, R., Mcllhagger, A.T., 2003. A modified system for design and analysis of 3D woven preforms. Compos. Part A 34, 503-509. 

Wigent, D., Sharp, K., Bogdanovich, A., Heider, D., Deflor, H., 2006. Integrated thermal management in materials based on 3-D woven preforms and co-infusion RTM. In CD Proceedings of SAMPE 2006 Technical Conference, Long Beach, CA, April 30-May 4, 2006. 

Shape weaving is the latest development in this area and provides a process that is automated and capable of large serial production. Cycle times of shell woven preforms are within some minutes. A textile design of the complicated 3D fabric construction needs to combine geometry and woven fabric requirements and is preferably done by special CAD software. Simulation software enables optimization of the woven 3D reinforcement according to stiffness requirements of a composite application. 

There are various definitions of 3D fabrics and structures because researchers and scientists differ in their opinions (Mohamed, 1990 Islam, 1999a Chen and Hearle, 2008 Khokar, 2008). In this chapter, any fabrics that take the shape of three dimensions are considered to be 3D fabrics. Woven preforms with substantial thicknesses, thick preforms, orthogonal preforms, or ones that have been made using a standard loom or special loom mechanisms and any woven 3D shaped preforms are considered to be 3D woven preforms in this chapter. 

A woven sine-wave structure is shown in Figure 9.40, and a complex woven preform is shown in Figure 9.41. The electronics can be placed into slots for various E-textiles applications. 

D woven preforms are woven directly into net shapes. The advantages of woven 3D preforms are as follows ... 

Figure 9.41 Complex woven preform (Courtesy of Bally Ribbon Mills).

The 2D conventional loom is modified to weave various 3D woven preforms. What kind of modification(s) should be carried out depends on the nature of preforms to be produced. The take-up and shedding motions are modified in many ways along with other tools that are also installed. Modified looms are used to produce thick panels, contour materials, polar materials, and complex 3D preforms. An unlimited number of 3D preforms and complex shapes can be woven on a modified loom with electronic Jacquard. Figure 9.60 shows a narrow fabric shuttle loom weaving a 50-mm-thick carbon panel. An orthogonal weave has been used with a dead pick motion so thatX, Y, and Z fibers are perpendicular to each other. 

One of the easiest 3D weave patterns to design is the 3D orthogonal weave pattern because all fibers are straight in the X, Y, or Z directions fiber crimp is minimal and can be eliminated from the calculatiOTis. To calculate the total number of Z yams required per square inch of 3D orthogonally woven preform, the preform thickness must be taken into account. The following equation assumes each Z fiber travels through the entire preform thickness. 

Development of In Situ Reinforced Polypropylene Fibers for Use in Formable Woven Preforms... 

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