Development of Composites Reinforced with Short Wavy Fibers
Abstract
In short fiber composites including nanocomposites, the load transfer efficiency among fibers is crucial in effecting superior composite properties. It is conceivable that this load transfer efficiency depends on the shape, aspect ratio, and surface area of the fiber. The effect of surface area of the reinforcing element is of particular importance because of the increasing use of nano particles in nanocomposites. It is well known that for the same volume, a material at nano scale possesses much greater surface areas than at larger scales. It is evident that more surface areas mean more load transfer paths and, thus, lower interfacial stresses between the reinforcement and the matrix. The lowering of interfacial stresses is expected to lead to higher composite strengths. In the previous period, we used model composite to reach the following conclusions: 1) Wavy fibers lower the interfacial stresses and thus increase the composite strength significantly, and 2) For the same fiber volume fraction, the composite with thinner fibers has higher strength than the composite with thicker fibers. In this reporting period, we continued to investigate the size effect of reinforcements. In addition to platelets, we also included spherical particulates of varying sizes. For the platelet reinforcement, composites are manufactured with steel platelets whose lateral dimensions are on the order of centimeters and thickness in the range of 0.01 - 1.0 mm. Pull-out tests are conducted and micromechanics models are developed to understand the reinforcing mechanisms and to develop a strength prediction method. For particle reinforcements, glass beads of 2000 micronmeter, 500 micronmeter, 200 micronmeter, 70 micronmeter and 6 micronmeter in diameter (mean size) and alumina particles of 70 micronmeter, 20 um, 3 micronmeter, and 50 nm in diameter are used together with vinyl ester to make composites for evaluating the size effect on the composite stiffness and strength properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2004
- Accession Number
- ADA428639
Entities
People
- Chintech Sun
Organizations
- Purdue University