Abstract: Fiber reinforced thermoplastic composites have wide application in aircraft structure for the excellent comprehensive advantages of the high toughness, long material storage period and short molding cycle, which have been regarded as the promising advanced aeronautical structure materials. The thermo-residual stresses will be produced in the molding processes of high processing temperature and cooling rates. The stresses caused by the mismatch in coefficients of the thermal expansion, anisotropy of the adjacent fabrics layers and thermal gradient distribution of the thermoplastic composite during the cooling process will play an important role in the mechanical properties of thermoplastic composites, which must be taken into consideration in the design of composite parts. It is beneficial to recognize the formation causes and development of the thermo-residual stresses to effectively control the residual stress level of the thermoplastic parts. The mechanism of thermo-residual stresses formation was firstly analyzed in three different levels in present study, i.e. constituent materials level, lamination plate′s level and the structure parts level. Moreover, testing methods of the thermo-residual stresses of the thermoplastic composites based on the previous literatures were also introduced. The advantages and disadvantages of these methods were evaluated as well.

Key words: thermoplastic composites, polymer matrix, thermo-residual stresses, test methods