Integral armor concepts are being developed by the Army and its contractors as practical lightweight material solutions to simultaneously address both ballistic and structural requirements for ground vehicle systems. The effects of thermal residual stress in an integral armor sandwich structure on the quality, in-service performance and long term durability of the finished component are of primary concern. The integral armor sandwich configuration consists of a discontinuous ceramic cored supported by laminated glass fiber reinforced face sheets. An analytic solution is developed in this work to predict the thermal residual stress development in the integral armor configuration. The analysis technique builds on the variational method which can be derived from the complementary energy of an admissible stress system in a unit-cell representation of the structure. The analytical solution is obtained through the total complementary energy which includes the thermal effects of the structure. The results suggest that the presence of a soft elastomeric layer between the ceramic core and composite laminates can significantly change the initially introduced thermal residual stresses associated with thermal expansion mishmatch. Parametric studies are conducted to investigate the effects of the elastomer interlayer on thermal residual stress development. The effects of material properties and layer thickness are examined. A two-dimensional finite element analysis for the same unit-cell configuration was also performed and results were found to compared favorably with the analytical results.
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