某大极孔比复合材料壳体结构设计及承压力学特性研究

Structural design and mechanical properties of a composite case with large pole hole ratio

通过开展某大极孔比固体火箭发动机复合材料壳体结构设计及水压试验研究,探究了其在内压载荷作用下的力学行为。采用CADWind进行缠绕线型规划及铺层设计,实现壳体的高保真有限元建模,根据复合材料渐进损伤原理(特性)分析了壳体承压性能,揭示了壳体大极孔端的失效机理,并通过水压爆破试验验证计算模型的准确性。结果表明,通过CADWind进行线型、铺层设计能有效支撑大极孔比壳体缠绕成型,壳体的铺层厚度、角度输出数据与实物更加吻合,可进一步提高有限元建模精度;其次,基于Hashin失效判据的渐进损伤失效分析方法实现了壳体的破坏位置、失效模式以及爆破压强的准确预测;最终,壳体计算爆破压强20.3 MPa,试验爆压19.5 MPa,计算误差4.6%,筒段应变计算结果与实测值基本吻合。

Through the structural design and hydraulic test of the composite case of a solid rocket motor with a large polar hole ratio,the mechanical behavior of the composite case under internal pressure was investigated.The high-fidelity finite element model of the case was implemented with the aid of the CADWind software used for winding pattern planning and ply design.The pressure bearing performance of the case was analyzed based on the progressive damage principle of composite materials,and the failure mechanism of the composite case was revealed.The accuracy of the calculation model was verified through the hydraulic burst test.The results show that the design of winding pattern type and layer by CADWind can effectively support fabrication of the case with large pole hole ratio.The thickness and angle of the case layer obtained by this method are more consistent with the real results,which can further improve the accuracy of finite element modeling;Based on the progressive damage failure analysis method of Hashin failure criterion,the damage law of the case under internal pressure is explored,and the failure location,failure mode and bursting pressure of the case can be accurately predicted.Finally,the burst pressure of the case is 20.3 MPa,test burst pressure is 19.5 MPa,the calculation error is 4.6%,and the calculated strain for case cylinder agrees with the measured value.