Analisi e sviluppo di strutture ibride per esperimenti di fisica delle particelle elementari

In the high energy physics experiments it is necessary the use of light structures, transparent to radiation with low value of thermal expansion and high strength. All these properties can be obtained by developing hybrid structures. The mechanical characteristic of hybrid structures and fiber-reinforced composite assemblies are limited by the presence of polymeric resins (adhesive or matrix), which have low mechanical strength and rigidity, are temperature dependents and reactive to the environment and to the active gas. Problems connected to the environmental degradation and to the low strength diminish by using epoxy resins. Still remain unsolved those problems related to low values of interlaminar stresses in the composite laminate and internal stress in the adhesive joints. The present work aimed to furnish systematic methodology for the characterization and development of hybrid structures used in particle physics experiments. The study covers the analysis of the deformations and stress distributions due to temperature and geometry variations on sandwich structures and composite assemblies. In particular it has been analysed the residual stresses caused by temperature variations between the working and assembly temperature. Due to precision in the positioning and the critical environment that the structure has to stand to (high temperature variations), all the adhesive assembly has been done at temperature below 40°C and by preference at room temperature.