Nonmetallics and composites
Development of standardized nonmetallic laminate materials, the manufacturing capability of cryogenic laminates, radiation effects and developments of basic cryogenic performance data were covered in two sessions on nonmetallics and composites. Papers described work underway in Japan, Germany and the US to expand the data base on the cryogenic performance of composite laminates unreinforced polymers and concretes. Most interesting was the expansion of these studies to include studies of the effect of anisotropy and biaxial stress states on the mechanical degradation of laminates at low temperatures and the permeability of laminates to helium. Data on the ability of reinforced and unreinforced polymers to resist impact forces at cryogenic temperatures was also addressed for the first time. These presentations reflect an increasing sophistication in studies relating to the usage of nonmetallic insulation and structural materials in fabrication of cryogenic systems. Presentations also addressed the continuing need for development of controlled laminate grades and reviewed the present state of their development. The capabilities for manufacturing such products to meet present and future industrial needs was also addressed. Radiation effects of the cryogenic performance of nonmetallic insulators was considered in only one presentation, reflecting a continued lack of emphasis on this very important question in the fabrication of functional magnet systems for magnetic fusion energy applications.