Fracture and Interface Studies of Aramid Reinforced Polyamide Composites: Compressive Effects and Critical Length Measurements.
Abstract
An investigation of interfacial properties and fiber compression in a class of composites utilizing polymer reinforcement of a polymer matrix was carried out. A model system incorporating single filaments of Kevlar-49 fiber in a nylon-6 matrix was prepared by solution casting the matrix around the fiber. Compression of the fiber caused by shrinkage during the casting process resulted in a fiber surface failure with the formation of kinks at approximately 45 deg to the fiber axis. Tensile testing of the compressed fibers revealed a decrease in initial tensile modulus and a about 20% reduction in strength at break. Measured fiber critical lengths fell within the theoretical range in almost every case. Relative changes in fragment length distributions occurred toward smaller critical lengths with exposure of the model composite to water. This suggests an increase in the apparent interfacial shear strength in the presence of water. An explanation for this behavior in terms of variable interfacial shear strength and ultimate fiber strength is proposed. The sensitivity of the properties of the highly anisotropic aramid fiber to composite dimensional changes is realized in both mechanical tests on the bare fiber and critical length measurements. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 20, 1981
- Accession Number
- ADA109506
Entities
People
- Richard J. Farris
- Roger S. Porter
- Steven J. Deteresa
Organizations
- University of Massachusetts Amherst