耐压液舱精细化分析与骨材变刚度设计

Refined analysis of pressure tank and variable stiffness design of frames

在有限元计算中,由于网格量的限制往往无法得到应力梯度较大位置的应力精确值,为解决此问题,基于外置式耐压液舱,采用子模型方法来提高计算精度,对规范与有限元结果差异较大的特征应力进行精细化分析,给出合理解释。基于子模型方法对纵骨进行变刚度设计,对纵骨自由翼缘上的总应力进行讨论。结果表明,纵骨变刚度设计效果明显,横舱壁根部纵骨自由翼缘上的总应力降低了26.43%,实肋板根部纵骨自由翼缘上的总应力降低了32.55%,变刚度设计是重量成本较低的降低纵骨自由翼缘总应力的可选方案。

In the finite element calculation,due to the limitation of the element number,it is hard to obtain the precise value of the stress at the position with a large stress gradient.To solve this problem,based on the external pressure tank,adopts the sub-model method to improve the calculation accuracy.A refined analysis is carried out on the values that differ greatly between the specification values and the finite element results,and a reasonable explanation is given.Based on the sub-model method,the longitudinal frame is designed with variable stiffness,the total stress on the free flange of the longitudinal is discussed.The results show that the effect of variable stiffness design of longitudinal frame is obvious,the total stress on the free flanges at the root of transverse bulkheads and solid floor is reduced by 26.43%,32.55%.The variable stiffness design is a lower weight cost option to reduce the total stress of the longitudinal frame free flange.