Multi-scale Modeling for the Stress Analysis of Acrylic Joints in a Hybrid Structure

The central detector at the Jiangmen Underground Neutrino Observatory (JUNO) is a hybrid structure system consisting of an inner acrylic sphere and an outer stainless steel reticulated shell. The stress distributions of the acrylic joints must be accurately simulated to avoid crazing. To balance the accuracy and efficiency of the stress analysis, a multi-scale modeling method using mixed-dimensional coupling is proposed. A framework and a generalized procedure are developed to instruct the modeling and analysis. A multi-scale model consisting of a single refined acrylic joint and equipped with simplified joints is proposed and discussed. A comparison of the results using the multi-scale model with a cluster of 3x3 refined joints reveals that the difference is less than 5%, while the ratio of the computation resource cost and the time consumption is approximately only 1/7 and 1/5, respectively. The stress distributions of the acrylic joints in the central detector are obtained using the proposed multi-scale model.