Multi-criteria shape optimization of a funnel in cathode ray tubes using a response surface model

One purpose of simulation describing the behaviors of structures is to optimize the performances within specific functional requirements and customers needs with respect to the design variables. For reduction of the volume of cathode ray tubes, the design of the glass geometry, especially funnel geometry, is essential while maintaining the internal vacuum pressure of the cathode ray tube. In order to describe the three-dimensional geometry of the funnel in cathode ray tubes, a higher-order response surface model is employed in the simulation model instead of non-uniform rational B-splines (NURBS) or Bezier curves because the response surface model is more robust for understanding the geometry change in finite element analysis. We formulate the design problem as a multi-criteria optimization because minimization of both volume and maximum stress is required. Using the response surface model of the geometry of the funnel and sequential quadratic programming within the process integration framework, the shape optimization of a funnel is successfully performed and the maximum stress level of the funnel is decreased by almost half.