Location

La Jolla, CA

Start Date

1-1-1993 12:00 AM

Description

The use of composite materials is proliferating these days. Their excellent strength-to- weight ratio has been the major reason for their popularity. Other reasons include: tailoring of desired properties, excellent corrosion properties, etc. Use of composites in underwater applications such as submarine hulls, due to their stealth properties, is becoming very attractive. Composites absorb sonar rays, making it difficult to detect submarines. Composites are also being used as pressure vessels and missile bodies. In these applications the structural shape is cylindrical or a surface of revolution. Very large composite cylinders with thickness of 3–4 inches have been manufactured for a variety of applications. These cylindrical shapes, in general, are manufactured by filament winding process. Continuous fiber is dipped in the adhesive and is wound on a mandrel. The fiber has to be under tension for good adhesion and reduced porosity. The cure process is an exothermic reaction and due to fiber tension and cooling, compressive stresses develop in the cylinders. It has been observed that due to these stresses the cylinders develop waviness in the fibers. It is not difficult to see that this waviness in fibers will result in reduced strength, of composites in compression, Garala [1], and increased fiber matrix debonding in tension. Hyer et al. [2] and Telegadas and Hyer [3] have studied the effect of fiber waviness on the stress state in hydrostatically loaded cylinders. The sample used by them had a single wave in a thermoset composite. The civil structural industry is finding new ways to use the composites. Small 3 inch long glass fiber wavy composites, wave length about 1 mm, are being tested as inclusions in reinforced concrete. The motivation for this study comes from the above applications of composites.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12B

Chapter

Chapter 5: Engineered Materials

Section

Composite Defects

Pages

1369-1374

DOI

10.1007/978-1-4615-2848-7_174

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Fabrication and NDE of Multi-Wave Thermoset GR/EP Composites

La Jolla, CA

The use of composite materials is proliferating these days. Their excellent strength-to- weight ratio has been the major reason for their popularity. Other reasons include: tailoring of desired properties, excellent corrosion properties, etc. Use of composites in underwater applications such as submarine hulls, due to their stealth properties, is becoming very attractive. Composites absorb sonar rays, making it difficult to detect submarines. Composites are also being used as pressure vessels and missile bodies. In these applications the structural shape is cylindrical or a surface of revolution. Very large composite cylinders with thickness of 3–4 inches have been manufactured for a variety of applications. These cylindrical shapes, in general, are manufactured by filament winding process. Continuous fiber is dipped in the adhesive and is wound on a mandrel. The fiber has to be under tension for good adhesion and reduced porosity. The cure process is an exothermic reaction and due to fiber tension and cooling, compressive stresses develop in the cylinders. It has been observed that due to these stresses the cylinders develop waviness in the fibers. It is not difficult to see that this waviness in fibers will result in reduced strength, of composites in compression, Garala [1], and increased fiber matrix debonding in tension. Hyer et al. [2] and Telegadas and Hyer [3] have studied the effect of fiber waviness on the stress state in hydrostatically loaded cylinders. The sample used by them had a single wave in a thermoset composite. The civil structural industry is finding new ways to use the composites. Small 3 inch long glass fiber wavy composites, wave length about 1 mm, are being tested as inclusions in reinforced concrete. The motivation for this study comes from the above applications of composites.