针对 NEPE 固体推进剂加压固化过程中液–固相变、等静压传压及残余应力演化难以统一描述的问题，建立了一种基于固化度驱动液–固相转换的顺序耦合数值模拟方法。以固化度 α 作为相态变量，引入凝胶点 αgel 作为液–固相变判据：当 α < αgel，采用液相等静压传压模型描述推进剂受压行为；当 α ≥ αgel 时，切换至固相本构模型并开始累计残余应力/应变。固化反应动力学、放热效应与热传导过程通过热–化学耦合分析获得温度场与固化度场，并在顺序耦合框架下传递至力学分析中，用于驱动材料状态判定及力学参数演化。通过用户子程序实现液–固相变条件下多物理场的协同计算，系统模拟了发动机在加载压力、固化及降温卸压全过程中的受压变形与残余应力演化行为。数值结果表明，液相阶段推进剂主要以静水压力形式传递外加载荷，未产生残余应力；进入固相阶段后，随着固化度提升，推进剂内形成固化交联网络转变为固相，壳体回弹收缩对固化与降温引起的体积收缩产生补偿作用。所提出的加压固化数值方法能够更合理地刻画壳体回弹发生的时序及其对残余应力释放的影响，最大残余应力和应变较现有仿真方法分别降低了 17.05% 和 20.83%。研究结果为 NEPE 推进剂加压固化工艺优化及残余应力控制提供了一种可靠的数值分析手段。

To address the difficulty of consistently describing the liquid–solid phase transition, isostatic pressure transmission, and residual stress evolution during the pressurized curing of NEPE solid propellants, a sequentially coupled numerical simulation method driven by the curing degree is proposed. The curing degree α is employed as the phase-state variable, and the gel point αgel is introduced as the criterion for the liquid–solid transition. When α＜αgel , a liquid-phase isostatic pressure transmission model is adopted to characterize the compressive response of the propellant. Once α≥αgel , the constitutive model switches to a solid-phase formulation, and the accumulation of residual stress and strain begins. The curing reaction kinetics, exothermic heat release, and heat transfer processes are solved through thermo–chemical coupling analysis to obtain the temperature and curing-degree fields. These fields are subsequently transferred to the mechanical analysis within a sequential coupling framework to govern material state determination and the evolution of mechanical properties. User-defined subroutines are employed to realize the multi-physics-field simulation under liquid–solid phase transition conditions. The proposed framework enables a systematic simulation of pressure-induced deformation and residual stress evolution throughout the entire process, including pressurization, curing, cooling, and depressurization of the motor. The numerical results indicate that during the liquid-phase stage, the propellant primarily transmits the external load in the form of hydrostatic pressure, without generating residual stress. Upon entering the solid phase, the increasing curing degree leads to the formation of a crosslinked network structure, transforming the propellant into a solid state. Meanwhile, the elastic rebound of the motor case compensates for the volumetric shrinkage induced by curing and cooling. The proposed pressurized curing simulation method provides a more physically consistent description of the timing of case rebound and its influence on residual stress relaxation. Compared with conventional simulation approaches, the maximum residual stress and strain are reduced by 17.05% and 20.83%, respectively. These results provide a reliable numerical tool for optimizing the pressurized curing process and controlling residual stresses in NEPE propellant grains.