圆柱壳三次非均匀有理B样条曲线变角度铺放轨迹设计及屈曲特性

Variable angle placement trajectory design of non-uniform rational B-splines curve and buckling property of cylindrical shell

  • 摘要: 基于三次非均匀有理B样条(NURBS)曲线,开展纤维变角度圆柱壳设计及其屈曲特性研究。首先,以三次NURBS曲线定义纤维变角度铺放参考轨迹,确定了变角度铺层的表示方式。其次,以纤维变角度铺层±<25(0.4)(0.8)75>和±<65(0.4)(0.8)10>为例,展示了三次NURBS曲线轴向平移铺层和周向平移铺层在圆柱壳上的纤维角度分布情况。然后,用纤维变角度铺层代替定刚度圆柱壳中的±45°铺层,对变刚度圆柱壳进行线性屈曲分析,对轴向平移圆柱壳、周向平移圆柱壳和定刚度圆柱壳进行对比。最后,在曲率半径约束下,研究权因子对圆柱壳屈曲性能的影响。结果表明:周向平移圆柱壳有着更好的屈曲性能;在曲率半径约束下,通过确定起始角、终止角和控制点参数得到屈曲性能优异的变刚度圆柱壳,而改变权因子能使变刚度圆柱壳的屈曲载荷再次提高。

     

    Abstract: Based on cubic non-uniform rational B-splines (NURBS) curve, the design and bucking property of cylindrical shell produced by fiber variable angle placement were studied. Firstly, the reference trajectory of fiber variable angle placement was defined by cubic NURBS curve, and the parameterized expression of fiber variable angle placement was determine. Secondly, taking the fiber variable angle placements ±<25(0.4)(0.8)75> and ±<65(0.4)(0.8)10> as examples, the fiber angle distributions of the axial and circumferential shift placements of the cubic NURBS curve on the cylindrical shell were demonstrated. Then, the ±45° placement of constant stiffness cylindrical shell was replaced by the fiber variable angle placements. The linear buckling analysis of the variable stiffness cylindrical shell was carried out, and the axial translation cylindrical shell, circumferential translation cylindrical shell and constant stiffness cylindrical shell were compared. Finally, the influence of weight factors on the buckling property was studied under the constraint of curvature radius. The results show that the circumferential translation cylindrical shell has better buckling performance. Under the constraint of curvature radius, the variable stiffness cylindrical shell with excellent buckling performance can be obtained by determining initial angle, termination angle and control point parameter, and the buckling load of the variable stiffness cylindrical shell can be increased again by changing the weight factor.

     

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