单片式核燃料板轧制过程的数值模拟研究

摘要

针对UMo合金单片式核燃料板锆合金包壳材料应变率相关的力学本构关系，推导出其三维应力更新算法，相应地编写了定义其本构关系的VUMAT子程序并验证了程序的正确性；建立了对UMo合金单片式板元件的框架轧制过程进行计算模拟的有限元模型；利用显式动力有限元法，计算分析了复合坯内部的变形以及接触压强在轧制过程中的演化规律。研究结果表明，利用VUMAT 用户材料子程序能方便正确地定义材料应变率相关的本构关系；燃料芯体与盖板之间的轧制接触压力随时间而演化，在靠近宽度方向的对称面处具有最大的接触压力。本研究为优化UMo合金单片式核燃料板的制造工艺参数提供了理论基础和计算手段。%For the strain‐rate‐dependent constitutive relation of zircaloy cladding in UMo monolithic nuclear fuel plates , the three‐dimensional stress updating algorithm was derived out , and the corresponding VUMAT subroutine to define its constitutive relation was developed and validated ;the finite element model was built to simulate the frame rolling process of UMo monolithic nuclear fuel plates ;with the explicit dynamic finite element method , the evolution rules of the deformation and contact pressure during the rolling process within the composite slab were obtained and analyzed .The research results indicate that it is convenient and efficient to define the strain‐rate‐dependent constitutive relations of materials with the user‐defined material subroutine VUMAT ;the rolling‐induced contact pressure between the fuel meat and the covers varies with time ,and the maximum pressure exits at the symmetric plane along the plate width direction .This study supplies a foundation and a computation method for optimi‐zing the processing parameters to manufacture UMo monolithic nuclear fuel plates .