自由变形技术在有限元网格重用中的应用

在现有自由变形技术的基础上,提出了基于三变量B样条空间的局部变形方法和对变形晶格顶点的控制方法,以及几何特征-变形晶格顶点-有限元网格节点的3层控制架构,克服了现有自由变形技术不能维持2次几何特征的缺点,实现了有限元网格模型中几何特征的参数化和有限元网格的重用;当几何模型的设计变量变化时,能够直接修改初始网格模型,节省了重复划分网格的工作量;同时,以复杂零件斜齿轮轴为例进行有限元网格模型几何特征参数的构建,更改部分关键尺寸,并校验了所生成的网格模型.结果表明,由所建模型变形后所得网格质量符合要求,从而验证了所提出的有限元网格重用方法的有效性与实用性.

Free-Form Deformation for Reuse of Mesh Models of Finite Element Analysis

Abstract： Meshing, which is very important to the result of finite element analysis (FEA), is often conducted manually. It takes a long time while the geometry model has to be re-meshed every time if the design is changed. A new method was presented in this paper that helped to reuse FEA meshes to improve efficiency with an extended technology of free-form deformation (FFD). This method generalized the previous FFD by allowing local deformation based on trivariate B spline and proposing a way to control vertexes of the FFD lattice. A three-level framework was presented that was “geometry feature-FFD lattice vertexes FEA nodes” to realize the reuse of FEA meshes with preserving geometry features continuous to the 2nd derivative and parameterizing mesh models. This approach saved time to re-mesh when the design variables change within a relatively narrow range. The result of a case study of helical gear shaft at the end of this paper shows that this method is able to apply deformation on the FEA meshes directly, keeping topology structures and geometry features stable instead of re-meshing from computer-aided design models.