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The multi-axis manned centrifuge is an important device for training pilots' directional cognitive ability and overcoming illusions. Its intensity check is a necessary part of structural design. The traditional quasi-static static analysis method can only directly analyze the structural strength problem of no more than two-axis nested rotation, but the multi-axis manned centrifuge has three or more than three-axis nested rotation. The flexible multi-body dynamics method can be used to analyze and determine the strength of the multi-axis rotating structure of the motion path, but the calculation time is long and the resource consumption is large, so it is difficult to fully assess the intensity of the structure. In this paper, a multi-axis centrifuge intensity check method based on multi-body dynamics combined with random sampling and finite element calculation is proposed. The calculation results can be obtained in a relatively short period of time, it is highly efficient and feasible, which is conducive to improve the accuracy of structural intensity verification of multi-axis nested rotating equipment, and provides important support for its structural design.

As a type of typical cellular foams,the macro-mechanical performances of rubber foams are mainly determined by its micro-structure and cell material properties.In the work reported here,several two dimensional（ 2D） finite element（ FE）models having regularly and randomly arranged elliptical and circular cells were constructed.The effects of cell shapes,cell distributing,and porosities on the hyperelastic large compressive deformations of rubber foams were explored.Obtained FE analysis results show that the compressive stress-strain curves of rubber foams present three deforming regions.The compressive stress-strain curves of circular cell models have longer plateau stage than those of elliptical cell models,and circular cell models have more steady mechanical performances than elliptical cell models do.If worked as shockproof cushions,circular cell structures are thus better than elliptical cell structures.

In soft lithography roof collapse is frequently observed on the stamp surface consisting of rectangular micro-grooves which yields unwanted contact between the sagged surface and the substrate. Deep understanding of the adhesive contact behavior is a key to design of high-performance collapse-resistant stamp. Both theoretical and numerical studies are presented for a single rectangular micro-groove in the middle of the stamp surface under applied pressure. The JKR-type adhesion solution is established by the principle of superposition and equivalent energy release rate, with a series of closed-form expressions derived which are consistent with previous studies. Finite element analysis (FEA) is performed based on virtual crack closure technique (VCCT) to investigate the roof collapse mechanism with interfacial adhesion and applied pressure considered. Comparison of theoretical, numerical, and experimental results demonstrates that both size effect and constitutive nonlinearity of the stamp on the self-collapse contact width are not obvious for shallow grooves but become prominent for deep grooves, so that the obtained analytical solution is limited to shallow grooves due to its assumptions of half-plane and linear elasticity adopted for the stamp. For deep grooves, the present FEA method shows potential to capture more accurate results. [ABSTRACT FROM AUTHOR]