Determination of Fiber Volume Fractions by Optical Numeric Volume Fraction Analysis

Waterbury, Mark C.; Drzal, Lawrence T.

doi:10.1177/073168448900800605

Cited by 36 publications

(9 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fiber volume fraction and void content of unidirectional specimens for all the panels tested in this study were determined by optical numeric iolume fraction analysis (ONVFA) that is described in detail in Reference [9]. One sample from each panel uas analyzed and measurements were obtained by averaging 15 images per sample, each containing approximately 1500 fibers.…”

Section: Methodsmentioning

confidence: 99%

Fiber-Matrix Adhesion and Its Effect on Composite Mechanical Properties: II. Longitudinal (0°) and Transverse (90°) Tensile and Flexure Behavior of Graphite/Epoxy Composites

Madhukar

Drzal

1991

Journal of Composite Materials

Self Cite

184

View full text Add to dashboard Cite

East Lansing. MI 48824 (Raeivod December 12. B89) (Revised Augur1 21. 1990)AB!TlXACl': An optimum level of interfacial bond strength between reinforcing fiber and a polymeric matrix in which it is placed is essential for acceptable composite mechanical properties and performance. The interfacial bond strength can be optimized only when the relationship between the level of fiber-matrix adhesion and thc mechanical and fracture behavior of composites is clearly understood. This study establishes the relationship between the fiber-matrix interfacial shear strength and 0" and 9 0 ' tensile and flexure p r o p t i e s of graphitdepoxy composites. A well defined and characterized graphite fiberlepoxy system was chosen in which the level of adhesion between fiber and matrix Mas changed by using the same gmphite fibers through the use of surface treatment and finish. The level of adhesion between the fiber and matrix associated with these changes resulted in an increase of fiber-matrix interfacial shear strength (ISS) by Over a factor of tvm while the fiber and matrix properties remained unchanged. The experimental results demonstrated that thc fiber surface modification did not have much effect on the tensile and flexural moduli and on the fiber dominated properties. However, the strengths and maximum strains that are governed by the matrix and interface properties were highly sensitive to the fiber surface modification. In addition, the major failure modes were also found to be affected by the fiber-matrix interfacial shear strength. 1. BACKGROUND HE SENSITIVITY OF the mechanical behavior of composite materials to the T fiber-matrix interfacial bond strength has long been realized [l-31. Longitudinal tensile failure of carbon fiber composites having low interfacial bond strength displays a broom-like fracture surface, while those having a high interfacial bond display a brittle fracture surface [4,5]. It has been qualitatively known 95 8 Joiiriial Of COhfPOSlTE MATERIALS, k' d. 25-Altgltst 1991

show abstract

Section: Methodsmentioning

confidence: 99%

Fiber-Matrix Adhesion and Its Effect on Composite Mechanical Properties: II. Longitudinal (0°) and Transverse (90°) Tensile and Flexure Behavior of Graphite/Epoxy Composites

Madhukar

Drzal

1991

Journal of Composite Materials

Self Cite

184

View full text Add to dashboard Cite

show abstract

“…Hg) was applied for the first 30 min of the 80°C soak period and vented to atmosphere for the remainder. Laminate quality was monitored by optic numeric volume fraction analysis [9] (ONVFA), a Michigan State University developed technique which allows quantitative assessment of the fiber volume fraction and void content using optical methods.…”

Section: Composite Fabricationmentioning

confidence: 99%

Glass fiber 'sizings' and their role in fiber-matrix adhesion

Drown¹,

Moussawi²,

Drzal³

1991

Journal of Adhesion Science and Technology

View full text Add to dashboard Cite

Silane coupling agents are but one of the many ingredients in commercial sizings that are applied to glass fibers. The action of epoxy-compatible silane coupling agents alone is to increase the fiber-matrix adhesion; however, the action of a silane coupling agent-containing sizing system is not well understood. Research has been conducted in order to determine to what degree an epoxycompatible glass fiber sizing alters the adhesion between fiber and matrix, as well as to what degree it changes the mechanical properties of the resulting composite. By using blends of epoxy-compatible sizing with bulk matrix, it has been possible to model the properties of the fiber-matrix interphase formed when the sizing interacts with the matrix during composite processing and fabrication. It has been shown in this case that the sizing's interaction with the matrix produces a material with a higher modulus, a greater tensile strength, but a lower toughness. The level of fiber-matrix adhesion increases along with a change in failure mode of the composite caused by the presence of the lower toughness interphase. The results from this study show that a chemical interaction theory of adhesion is not sufficient to explain the effect of fiber-matrix adhesion on composite properties. An interphasebased theory in which the mechanical properties of the interphase are considered along with the chemical interactions between the fiber surface and the sizing offers the best approach for developing these relationships.

show abstract

“…Fiber volume fraction and void content of the carbon fiber unidirectional prepreg for the different samples were determined by optical numeric volume fraction analysis (ONVfA) that is described in detail by Waterbury and Drzal, (1989). Fiber volume fractions in this method are directly obtained by multiplying the number of fibers in each image by the average area of a fiber and dividing by the area of the counting field without additional calibration factors.…”

Section: Determination Of Fiber Volume Fractionmentioning

confidence: 99%

Mode-II Fracture at the Interface between a Base and a Repair Graphite/Epoxy Laminates

Jarrah

Tahat

Hoa

2002

Journal of Reinforced Plastics and Composites

View full text Add to dashboard Cite

Experimental investigation of the characteristics of the interface between a base laminate [08] T and a repair laminate [08] T was carried out through Mode II fracture tests, compliance calibration tests, and microscopic observations. The material used for manufacturing the test samples is unidirectional carbon fiber prepreg (Newport Composites NCT-301 graphite/epoxy). The laminate lay-up used in all experiments was [016] T.The specimens were subjected to variations in the autoclave pressure in the repair curing cycle. A standard sample (reference) was subjected to the manufacture recommended cure cycle. The repair samples were subjected to the manufacturer recommended curing cycle (for temperature) with different values for pressure. Results show a significant effect of pressure. However, the effect of the magnitude of the pressure is not significant after some threshold values. More than 28% drop in the fracture toughness is experienced by the lack of bonding between the older previously cured matrix and the newly added composite laminate. There is some difference between the Mode-II test and compliance calibration test, but no preference, in terms of accuracy, can be given to what method to be used to obtain Mode II fracture toughness.

show abstract

Determination of Fiber Volume Fractions by Optical Numeric Volume Fraction Analysis

Cited by 36 publications

References 1 publication

Fiber-Matrix Adhesion and Its Effect on Composite Mechanical Properties: II. Longitudinal (0°) and Transverse (90°) Tensile and Flexure Behavior of Graphite/Epoxy Composites

Fiber-Matrix Adhesion and Its Effect on Composite Mechanical Properties: II. Longitudinal (0°) and Transverse (90°) Tensile and Flexure Behavior of Graphite/Epoxy Composites

Glass fiber 'sizings' and their role in fiber-matrix adhesion

Mode-II Fracture at the Interface between a Base and a Repair Graphite/Epoxy Laminates

Contact Info

Product

Resources

About