## 1 Introduction
[PERSON] and [PERSON] [PERSON] and [PERSON] (2015) investigated the effects of moisture on thermal and mechanical properties and the moisture absorption of glass-fiber/polyetherimide (PEI) laminated composites, and the laminated composites were exposed to hydrothermal aging environment under two different temperatures and high moisture rates. The hydrothermal aging laminates comprised a large number of moisture, causing a decrease in the glass transition temperature and degradation in mechanical properties. [PERSON] et al. [PERSON] et al. (2016) studied the hygrothermal aging properties of carbon fiber/bismaleimide (BMI) composites, and measured the water diffusivity through the three wet-dry cycles of BMI resin, reinforced with unidirectional carbon fiber CCF300/QY9511 composites. The results showed that the re-absorption of CCF300/QY9511 composites exhibit a higher amplitude of diffusivity but a lower saturated moisture content. [PERSON] et al. [PERSON] et al. (2016) extensively investigated the low velocity impact tests of laminated composites in an ambient hygrothermal environment, and the unidirectional and crosgly glass fiber reinforced plastic (GFRP) laminates were placed in a conditioning chamber for a maximum of eight moisture cycles from 50 to 100 \({}^{\circ}\)C. The impact loading decreases and the deflection increases with cycling moisture levels. [PERSON] et al. [PERSON] et al. (2016) analyzed the micro-cracking of polymer matrix composites through using multiaxial multi-ply stitched carbon preforms, subjected to purely cyclic hygrothermal loadings. The specific cracks occurred within the resin transverse channels sur-rounding the stitches, showing that hygrothermal damage is different to that caused by the mechanical loadings [PERSON] et al. (2015). [PERSON] et al. (2016) designed a 24 h cyclic hygrothermal aging spectrum, containing cyclical variations between temperature and moisture, which aimed to simulate a mission environment for an advanced subsonic aircraft. Durability research on the hygrothermal aging material system was carried out. Experiments showed that the initial and residual tensile properties after hygrothermal aging were almost unaffected by hygrothermal aging. However, residual strength and dynamic stiffness were significantly decreased at high temperature. Recently, [PERSON] et al. [PERSON] et al. (2016) experimentally investigated the high velocity impact performance of the T700/TDE85 carbon/epoxy composites after cyclic hygrothermal aging in an environmental chamber at a constant temperature and humidity (70 \({}^{\circ}\)C, 95%RH) for the first time. They found that the ballistic limit of a carbon/epoxy composite decreases after long-time hygrothermal aging. [PERSON] et al. [PERSON] et al. (2015) reported the thermal aging on the compressive behavior of pure epoxy and 3D braided composites, the epoxy, and the 3D braided composites were aged in air for 1, 2, 4, 8, and 16 days at 180 \({}^{\circ}\)C. The experiments and the micrograph of samples by using the scanning electron microscope (SEM) revealed that epoxy initiated degradation in regions close to the surface layer, and the compressive behavior degradation was mainly from interface degradation and crack propagation after high temperature aging. [PERSON] [31] carried out tensile tests of 3D four-step braided composite after heat accelerated aging under 150 and 180 \({}^{\circ}\)C for 60, 120 and 180 h. After aging, they found that the structure of braided composites still kept integrity, and the tensile performance degraded less. To our knowledge, much research has been focused on the mechanical properties considering the hygothermal aging effects of resin-based laminated composites except the above two papers, with respect to 3D braided composites. There are even fewer articles on the 3D braided composite after cyclic hygothermal aging. Therefore, it is of a certain significance to research the 3D braided composite after cyclic hygothermal aging.