To explore the overall structural reliability of hypersonic vehicles and its influencing factors

and ensure the structural safety of the vehicles when performing missions

a new subdomain subinterval method for analyzing the structural strength reliability of hypersonic vehicles is proposed by combining the stress-strength interference model with the interval number. Firstly

the moment of each force surface of a hypersonic vehicle under different flight conditions is analyzed. Secondly

the vehicles structure is approximated as an equivalent cantilever beam

considering the uncertainties of its moment

width and height

which are expressed as interval numbers. Then

considering the degradation of the structural strength over time

a non-probabilistic reliability analysis is carried out based on the stress-strength interference model

and a dynamic reliability model of the vehicles structure is established. Finally

a new sub-domain sub-interval method is proposed to analyze the exponential degradation characteristics of the structural strength and the impacts of the flight dynamics on the structural reliability. The simulation results show that the subdomain subinterval method is more accurate than the traditional Monte Carlo method with the same number of sampling points

which verifies the feasibility and validity of the proposed method. The reliability of the vehicle decreases gradually with the exponential degradation of the structural strength of the vehicle. In addition

the flight dynamics of the vehicle has a major impact on the structural reliability

in which the reliability of the vehicle increases with the increase of the height of flight

and decreases with the increase of the velocity as well as the angle of attack.