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Introduction 



THE MATERIAL 



Fiberglass reinforced plasties are at this time competitive high performance structural 

 materials. The basic fibers are among the strongest structural elements known. Although 

 it would be inadvisable to consider reinforced plastics as the universally superior structural 

 material, they are clearly superior in many cases and competitive in others. It may also 

 be expected that additional research and improved processes will further upgrade the basic 

 materials and the finished products. New confidence in design, coupled with experience in 

 dependable commercial production, will permit widespread diversification of economically 

 sound applications. 



Although the strength to weight performance has indicated an advantage over some of the 

 more familiar materials, there are many other characteristics which have influenced the 

 increasing use of this material. Desirable compound curvatures can readily be achieved 

 with this moldable material which can be formed as easily in one shape as another without 

 the use of expensive forming tools. The ability to construct a one piece structure, elimi- 

 nating complex load carrying joints, improves the performance and dependability of the 

 complete structure. Particularly in comparison with wooden structures, fiberglass rein- 

 forced plastics used in an integral structural design eliminates a wide assortment of fasten- 

 ings and hardware. 



In considering the design of a structure to carry different types of loads, variation in 

 strength can be easily accomplished in any portion of the structure, with the same basic 

 materials, by simply changing the cross-section and orienting the high strength fibers in the 

 direction of stress. Large tension loads can be efficiently supported by using cloth or uni- 

 directional fibers oriented so as to be aligned with the direction of load. An impact resis- 

 tant area can be created by increasing laminate thickness locally with reinforcements se- 

 lected for high impact strength and oriented so as to be equally good in all directions. To 

 support bending loads, stiffeners can be added to a panel in a conventional manner, or sand- 

 wich construction may be used. In any economic analysis, this factor must receive con- 

 siderable attention. The same raw materials of fiberglass and resin in the stock room will 

 produce an unlimited variety of thicknesses and forms. The equivalent of I beams, angle 

 stiffeners and extruded sections are all available. No longer are the forms and sections 

 limited to the availability of certain standard stock items. The rib and plate configuration of 

 most structures need not be tailored specifically to the dimensions of familiar components. 

 Modification and correction can be accomplished directly without delay and without major ad- 

 justment of expensive tooling. With proper design many internal components heretofore re- 

 quiring individual installation can be easily combined with the primary strength structure in 

 a single molding operation. 



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