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Structural properties of laminated Douglas fir/epoxy composite materialThis publication contains a compilation of static and fatigue strength data for laminated-wood material made from Douglas fir and epoxy. Results of tests conducted by several organizations are correlated to provide insight into the effects of variables such as moisture, size, lamina-to-lamina joint design, wood veneer grade, and the ratio of cyclic stress to steady stress during fatigue testing. These test data were originally obtained during development of wood rotor blades for large-scale wind turbines of the horizontal-axis (propeller) configuration. Most of the strength property data in this compilation are not found in the published literature. Test sections ranged from round cylinders 2.25 in. in diameter to rectangular slabs 6 by 24 in. in cross section and approximately 30 ft. long. All specimens were made from Douglas fir veneers 0.10 in. thick, bonded together with the WEST epoxy system developed for fabrication and repair of wood boats. Loading was usually parallel to the grain. Size effects (reduction in strength with increase in test volume) are observed in some of the test data, and a simple mathematical model is presented that includes the probability of failure. General characteristics of the wood/epoxy laminate are discussed, including features that make it useful for a wide variety of applications.
Document ID
Document Type
Other - NASA Reference Publication (RP)
Spera, David A.
(Sverdrup Technology, Inc., Cleveland OH., United States)
Esgar, Jack B.
(Gougeon Bros., Inc., Bay City MI., United States)
Gougeon, Meade
(NASA Lewis Research Center Cleveland, OH, United States)
Zuteck, Michael D.
(Gougeon Bros., Inc., Bay City MI., United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1990
Subject Category
Composite Materials
Report/Patent Number
NAS 1.61:1236
Accession Number
Funding Number(s)
PROJECT: RTOP 776-33-41
Distribution Limits
Work of the US Gov. Public Use Permitted.
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