A sub-domain size optimization method is conducted to design degraded negative Poisson’s ratio honeycomb structures, which could fully utilize the material behavior, such as minimum weight, maximum stiffness and maximum strength etc. The flexural stiffness of negative Poisson’s ratio honeycomb structure is greatly associated with the geometry size, which are obtained by geometry size parameter analysis from the representative volume cell of negative Poisson’s ratio honeycomb sandwich structure. A three-point bending specimen is designed by sub-domain size optimization method, which is verified by bending experiments. The optimal three-point bending specimen with graded negative Poisson’s ratio honeycomb core have the largest bearing capacities and relatively lower weight. The variable thickness wing structure with graded negative Poisson’s ratio honeycomb core is also designed by using the sub-domain size optimization method.

The effect of temperature on the mechanical behavior of carbon fiber reinforced polyphenylenesulfide (PPS) composites was investigated by compressive and flexural tests from ambient temperature up to 150°C. The failure morphologies of the C/PPS composites were analyzed to identify the variation of failure modes. Related results showed that the mechanical behavior of C/PPS composites decreased severely with the increase of temperature due to the softening of matrix. The PPS resin film tensile test was carried out and the PPS matrix behavior was recognized as the main factor to dominate the mechanical behavior of composites under compressive/flexural loading at elevated temperatures. It can be found that there was an approximate linear relationship between the compression properties of C/PPS composites and the PPS matrix. The dependence of failure modes of composites on temperatures was closely related to the mechanical behavior of PPS matrix.