T-spline and isogeometric analysis-based die surface springback compensation method

Abstract

The invention discloses a T-spline and isogeometric analysis-based die surface springback compensation method. The method comprises (1) a stress iteration die surface compensation method and (2) a displacement iteration die surface compensation method. The stress iteration die surface compensation method comprises the steps of 1, converting a trimmed NURBS model into T-splines; 2, splicing the T-splines; 3, performing Bezier extraction to obtain an adaptive analysis model; 4, performing forming simulation; 5, calculating deformation force; 6, performing springback simulation; 7, calculating a shape error, and if a condition is met, going to the step 9, otherwise, going to the step 8; 8, reversely applying the deformation force to the adaptive analysis model to perform simulation, and going to the step 4; and 9, modifying an initial T-spline model. The displacement iteration die surface compensation method comprises the steps of 1, converting the trimmed NURBS model into the T-splines; 2, splicing the T-splines; 3, performing the Bezier extraction to obtain the adaptive analysis model; 4, performing the forming simulation; 5, calculating the deformation force; 6, calculating a deviation of a control vertex; 7, calculating the shape error, and if the condition is met, going to the step 9, otherwise, going to the step 8; 8, reversely applying the deviation of the control vertex to the adaptive analysis model to perform simulation, and going to the step 4; and 9, modifying the initial T-spline model. According to the method, numerical simulation of a plate forming springback process and compensation of a simulation result are realized.

Description

technical field [0001] The invention provides a mold surface springback compensation method based on T-spline and isogeometric analysis. The spline surface is used to construct the mold surface, and the springback process of stamping forming is numerically simulated by using the isogeometric analysis based on T-spline, and the mold surface is compensated according to the numerical calculation results. The T-splines (T-splines) that the present invention refers to is a kind of surface modeling method proposed by ThomasW.Sederberg et al. in the document T-splines and T-NURCCs in 2003, and belongs to the technical field of computer graphics and surface modeling; etc. Geometric analysis refers to a numerical analysis method proposed by T.J.R Hughes in the document Isogeometric analysis: CAD, finite elements, NURBS, exact geometry and meshrefinement in 2005, which belongs to the field of numerical calculation. Mold surface springback compensation refers to the method of changing t...

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Problems solved by technology

Finite element analysis requires grid division to discretize the design model, which introduces model accuracy errors

Secondly, in the calculation process, the model needs to be refined for the severe deformation area, and the analysis error of model refinement is introduced again.

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