Excessive vibration of aircraft wings during flight is harmful and may cause propagation of existing cracks in the material, leading to catastrophic failures as a result of material fatigue. This study investigates th...Excessive vibration of aircraft wings during flight is harmful and may cause propagation of existing cracks in the material, leading to catastrophic failures as a result of material fatigue. This study investigates the variations of modal characteristics of aircraft wings with respect to changes in the structural configurations. We develop parametric Computer-Aided Design (CAD) models to capture new design intend on the aircraft wing architectures. Subsequent Finite Element Analysis (FEA) based vibration analysis is performed to study the effects of architecture changes on the wing’s natural frequencies and mode shapes. It is concluded that the spar placement and the number of ribs have significant influence on the wing’s natural vibration properties. Integrating CAD modelling and FEA vibration analysis enables designers to develop alternative wing architectures to implement design requirements in the preliminary design stage.展开更多
随着中国改革开放,经济飞速发展,我国桥梁分别在桥梁建造技术、桥梁结构、高性能材料、信息化技术及标准规范等各方面取得了巨大成就,这也标志着我国桥梁建设正向着大跨径方向发展。连续体系桥具有跨中弯矩小、抗震和抗扭性能好等优点,R...随着中国改革开放,经济飞速发展,我国桥梁分别在桥梁建造技术、桥梁结构、高性能材料、信息化技术及标准规范等各方面取得了巨大成就,这也标志着我国桥梁建设正向着大跨径方向发展。连续体系桥具有跨中弯矩小、抗震和抗扭性能好等优点,Revit作为BIM的代表软件为房屋建筑提供了很大的便利,但是在复杂桥梁上面却显露出了很多弊端。而Dynamo具有强大的处理数据能力和空间异型构件的功能。本文基于Revit API技术,通过Visual Studio 2019平台,运用C#语言进行二次开发,通过界面开发分别从BIM模型中获取几何构造与物理信息,同时基于Revit模型进行网格划分,将BIM模型转换为有限元分析模型,大大的降低了有限元分析前处理的操作门槛,最后用连续刚构桥梁的工程实例验证了参数化建模以及模型转换接口的适用性和准确性。展开更多
文摘Excessive vibration of aircraft wings during flight is harmful and may cause propagation of existing cracks in the material, leading to catastrophic failures as a result of material fatigue. This study investigates the variations of modal characteristics of aircraft wings with respect to changes in the structural configurations. We develop parametric Computer-Aided Design (CAD) models to capture new design intend on the aircraft wing architectures. Subsequent Finite Element Analysis (FEA) based vibration analysis is performed to study the effects of architecture changes on the wing’s natural frequencies and mode shapes. It is concluded that the spar placement and the number of ribs have significant influence on the wing’s natural vibration properties. Integrating CAD modelling and FEA vibration analysis enables designers to develop alternative wing architectures to implement design requirements in the preliminary design stage.
文摘随着中国改革开放,经济飞速发展,我国桥梁分别在桥梁建造技术、桥梁结构、高性能材料、信息化技术及标准规范等各方面取得了巨大成就,这也标志着我国桥梁建设正向着大跨径方向发展。连续体系桥具有跨中弯矩小、抗震和抗扭性能好等优点,Revit作为BIM的代表软件为房屋建筑提供了很大的便利,但是在复杂桥梁上面却显露出了很多弊端。而Dynamo具有强大的处理数据能力和空间异型构件的功能。本文基于Revit API技术,通过Visual Studio 2019平台,运用C#语言进行二次开发,通过界面开发分别从BIM模型中获取几何构造与物理信息,同时基于Revit模型进行网格划分,将BIM模型转换为有限元分析模型,大大的降低了有限元分析前处理的操作门槛,最后用连续刚构桥梁的工程实例验证了参数化建模以及模型转换接口的适用性和准确性。
文摘【目的】阅读理解是人类最重要的认知能力,评价人类的阅读理解能力需要客观指标。【方法】提出一种基于脑磁图(magnetoencephalogram, MEG)虚相干脑功能连接的预测模型,使用虚相干算法构建全脑MEG功能连接,并通过单变量特征选择算法对特征进行选择,采用偏最小二乘回归(Partial Least Squares, PLS)构建预测模型对阅读理解能力进行预测。【结果】基于MEG虚相干功能连接的偏最小二乘回归模型可以成功预测阅读理解分数;进行单变量特征选择的模型预测性能更高、预测更准确(R^(2)[PVT-Language]=0.524,MSE[PVT-Language]=5.042;R^(2)[ORRT-Language]=0.536,MSE[ORRT-Language]=5.142),并且发现采用与阅读理解相关的任务态数据集比静息态数据集更适合用来预测阅读理解能力,且特征选择的功能连接更精确。【结论】基于MEG虚相干功能连接的PLS预测模型可以用来客观评价人类阅读理解能力。
