Research on Axial Stiffness of Wire Braid Based on Multi-level Finite Element Method
Wire braid which is widely used in aerospace pressurized transport pipelines has complex nonlinear mechanical properties,and its axial mechanical behavior mechanism and simulation modeling method are investigated in this paper.The wire braid's three-dimensional geometric modeling is achieved using the multi-strand side-by-side tubular braiding structure modeling method.At a fine scale,the columnar braiding single-cell model of the wire braid is established based on the periodicity theory.The single-cell model simulates the axial tensile working condition of the wire braid with and without a mandrel under two boundaries.The calculation results indicate a significant difference in the axial stiffness of the wire braid under the two boundaries.A simplified analytical model of a wire braid is proposed to compare the differences between the results of the spiral beam model and the single-cell model.A correction method for the spiral beam model is proposed based on the principle of stiffness equivalence.The simulation example demonstrates that the corrected spiral beam model accurately calculates the axial reaction force of the compensator with internal pressure,with good agreement with the test results.The error is significantly reduced compared to the uncorrected spiral beam model.The helical beam model and correction method provide a reference for further mechanical analysis of sleeve expansion joints.
tubular braided structuresaxial stiffnessperiodic boundariesnonlinear finite elements
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