物理模拟与数据驱动混合的Z型立柱片剪切刚度认知预测方法

A Cognitive Prediction Method of Shear Stiffness of Upright Frames in Z-pattern Based on the Physical Simulation and Data-driven

高层工业货架的货载量通常远大于结构自重,立柱片剪切刚度对货架整体的侧向稳定性至关重要。由于结构尺寸及连接方式的多样性,目前建立较为通用的立柱片剪切刚度计算模型还比较困难。以常见的Z型立柱片为例,提出了物理模拟与数据驱动混合的剪切刚度认知预测方法,以期提高工业货架抗侧倾设计的科学决策能力。首先,建立了基于力学性能试验的立柱片剪切刚度有限元仿真模型,并获取了不同立柱片结构的剪切刚度分析数据集;其次,采用XGBOOST算法建立了立柱片剪切刚度智能化预测模型;相比于卷积神经网络和长短期记忆网络,其预测效率较高且更接近于有限元数值计算,便于立柱片剪切性能的快速评估。以此为基础,选取SHAP(Shapley additive explanation,SHAP)值可视化分析方法对立柱片预测模型计算结果进行理解与认知。重要性分数显示,改善立柱片剪切性能的关键在于斜横撑结构的设计;而立柱片跨距对剪切性能影响相对有限,可以根据需要灵活配置。另外SHAP摘要图和依赖图显示,分离型斜横撑配置模式下增大结构件规格尺寸可以明显提高立柱片的剪切刚度值。

The living load of high-rise industrial rack is usually much greater than the dead weight of structure,so the shear stiffness of upright frame is crucial for the overall lateral stability of the rack.Due to the variety of the size and the connection of structural components,it is still difficult to build a general analytical model at present.Taking the upright frame in Z-pattern as an example,based on the physical simulation and data-driven method,a cognitive prediction model on shear stiffness of upright frame is proposed.Firstly,based on the mechanical test,the finite element simulations of shear stiffness of upright frame were made to obtain the shear stiffness data sets of different upright frame structures.Secondly,the XGBOOST algorithm was used to train the intelligent prediction model of shear stiffness.In contrast with the convolutional neural network and long short-term memory network,the prediction results of the XGBOOST algorithm are more efficient and closer to the finite element method.On this basis,the results of prediction model are interpreted and understood with the visual method of SHapley additive exPlanation(SHAP).By the importance score analysis,it is found that the shear performance of the upright frame is mainly determined on the design of the bracing configuration,and the distance between two uprights has relatively limited influence on the shear performance which could be flexibly configured according to the user’s requirements.What’s more,the SHAP summary plots and dependency plots showed that the shear stiffness of upright frame is significantly increased by enlarging the dimensions of structural members under the separation configuration of bracing members.