基于SPH方法的航天结构件铸造过程多数学模型模拟研究

Aerospace structural components are basically low-profile disk parts with thin walls and complicated structure, which always features difficult quality control. Performing numerical simulation of casting process is of great scientific and practical significance. Most of the commonly used grid-based calculation methods have the problem that they are difficult to deal with extremely large grid deformation and motion interface tracking, and difficult to handle systems containing two or more phases of flow. Besides, we have not seen any establishment of SPH-based shrinkage prediction model specific to casting solidification process or any reporting about SPH-based calculation model specific to casting stress analysis. Based on the established simulation model of single-phase-flow SPH Casting Filling Process, this Project is intended to establish Simulation Model of SPH-Based Gas-Liquid-Solid Three-Phase-Flow Casting Filling Process by introducing surface tension model and motion model of rigid bodies, which provides a theoretical basis for predicting casting defects such as slag inclusion and air entrapment; Meanwhile it intends to establish a SPH-based shrinkage Prediction Model specific to casting solidification process and SPH-based calculation model specific to Casting Stress Analysis, which considers the complex stress-strain constitutive relation between three stages: liquid, solid-liquid coexistence and solid-state.

航天结构件基本都属于外形低矮、薄壁的盘类件，且结构复杂，长期存在质量控制难等缺点，进行铸造过程数值模拟研究具有重要的科学意义和应用价值。常用的基于网格的计算方法多存在难以处理极大网格变形和运动交界面跟踪等问题，同时不易处理包含两相以上流体的系统，且未见有针对铸造凝固过程基于SPH法的缩孔预测模型建立和针对铸造应力分析的基于SPH法的计算模型建立的报道。本项目拟以已建立的单相流SPH铸造充型过程模拟计算模型为基础，引入表面张力模型和刚体的运动模型，建立基于SPH铸造充型过程气液固三相流模拟计算模型，为预测夹渣、卷气等铸造缺陷提供了理论依据；同时拟建立针对铸造凝固过程基于SPH法的缩孔预测模型和针对铸造应力分析的，考虑液态、固液两相共存和固态三种情况复杂应力应变本构关系的基于SPH法含损伤预测的计算模型。

航天结构件基本都属于外形低矮、薄壁的盘类件，且结构复杂，长期存在质量控制难等缺点。常用的基于网格的计算方法多存在难以处理极大网格变形和运动交界面跟踪等问题，同时不易处理包含两相以上流体的系统，且未见有针对铸造凝固过程基于SPH法的缩孔预测模型建立和针对铸造应力分析的基于SPH-FEM耦合方法的计算模型建立的报道。本项目以已建立的单相流SPH铸造充型过程模拟计算模型为基础，引入表面张力模型和刚体的运动模型，建立了基于SPH铸造充型过程气液固三相流模拟计算模型，为预测夹渣、卷气等铸造缺陷提供了理论依据。建立了针对铸造凝固过程基于SPH法的缩孔预测模型。将SPH程序计算充型结束时刻结果导入FEM程序进行凝固阶段计算；以搜索到的SPH粒子与FEM节点距离为系数进行加权平均，得到FEM节点初始信息；同时考虑了液态、固液两相共存和固态三种情况复杂应力应变本构关系；构建了针对铸造应力分析的SPH-FEM耦合计算模型。根据研究成果，已见刊学术论文14篇，其中SCI论文8篇、中文核心期刊论文6篇；授权国家发明专利3项、公开国家发明专利3项、实现专利转化应用3项；毕业硕士7名，均获得硕士学位；组织/参加学术会议5次。