Short-fiber reinforced composites are widely used for the mass production of high-resistance products with complex shapes. Efficient structural design requires consideration of plasticity and anisotropy. This paper presents a method for the calibration of a general material model for stress–strain curve prediction for short-fiber reinforced composites with different fiber mass fractions. A Mori–Tanaka homogenization scheme and the J2 plasticity model with layered defined fiber orientation were used. The hardening laws: power, exponential, and exponential and linear were compared. The models were calibrated using experimental results for melt front, orientation tensor analysis, fiber length, and diameter and tension according to ISO 527-2, for samples of PA6 which were either non-reinforced, or reinforced with 10%, 15%, 20%, and 30% carbon fiber mass fractions. The novelty of this study lies in the transition from the strain–stress space to the strain–stress–fiber fraction space in the approximation of the material model parameters. We found it necessary to significantly reduce the fiber aspect ratio for the correct prediction of the mechanical characteristics of a composite using the Mori–Tanaka scheme. This deviation was caused by the ideal solution of ellipsoidal inclusion in this homogenization scheme. The calculated strength limits using Tsai–Hill failure criteria, based on strain, could be used as a first approximation for failure prediction.

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Abstract.We consider the problem of implementation of non-resonant motion at descent of a spacecraft with small mass and aerodynamic asymmetries in the low-density atmosphere of Mars. A controllable decrease in the mass asymmetry contributes to implementation of non-resonant motion of the spacecraft. We introduce an analytical control law for the magnitude of asymmetry. The results of numerical simulation of spherical motion of a spacecraft with controllable asymmetry are included.Keywords: spacecraft, resonance, control, atmosphere, asymmetry Citation: Lyubimov VV, Kurkina EV. Simulation of the dynamics of nonresonant motion in a controlled descent of an asymmetric spacecraft in the lowdensity atmosphere.

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