Experimental and Theoretical Investigation of Mechanically Fastened Composites
Abstract
The contractors conducted an experimental and analytical study of the mechanics of fasteners in FGRP composites. Areas of study considered in the contract included multiple-fastener arrays, load spreading washers of three types, bolt preload effects, field measurement, developement of analytical and experimental methods, parametric studies, and creation of design codes. A comprehensive study of literature pertaining to methods of mechanically fastening composites was undertaken, and a summary survey is included herein. Experimental methods consisted primarily of high-sensitivity, three-axis moire interferometry with digital data acquisition and data reduction. The appropriate apparatus and procedures were established as part of the contract effort. Analytical methods centered upon the boundary element approach. Algorithms and codes which yield stress strain fields for anisotropic materials in multiply connected geometries were created. A bolt load transducer was developed for determining joint loads in the field. Resistance strain gages were used to verify in plane strains measured by moire methods. Poorly fitted pins or tilted pins effect strain field drastically. Strain gage results were between the ideal case and the tilted-pin strain readings. Stress concentrations were reduced by judicious use of fastener arrays and conical washers with high bolt tension. Keywords: Composites, Fastener, Moire, Finite element, Boundary element, Fastener arrays, Washers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1987
- Accession Number
- ADA185896
Entities
People
- David Sikarskie
- Gary Cloud
- Micahel Bayer
- Pedro H. Franco
Organizations
- Michigan State University