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A Novel Structural Optimization Method and a Case Study Based on a CHS X-Joint
Xingqi Liu,Weitong Yi,Hailin Sun,Lei Zhu,Xi Chen 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4
In this paper, a new structural optimization method, “percentage structure optimization”, is presented. This method is obtained by using fi nite element method (FEM) to reduce a specifi c proportion of the stress ineffi cient element reduction, which is called the "structural optimization percentage index". In addition, an evaluation index of the optimized structure, “economic benefi t index”, is introduced. Compared with the existing structural optimization methods, the optimization process is smoother and the results are more controllable. Moreover, the method of evaluating the optimization results through the “economic benefi t index” pays more attention to the economic benefi ts of the project, and can achieve the balance between the minimization of material and the detention of bearing capacity to maximize the economic benefi ts. On the basis of the existing experiment, using ANSYS 17.0 software, two Circular Hollow Sections (CHS) X-joints are optimized by "structural optimization percentage index" of 5, 10 and 15%, and "economic benefi t index" is adopted as the judgment condition of the optimization results. The results show that the method can not only guarantee the bearing capacity, but also save materials as much as possible, and verify the reliability of the new structural optimization method.
( Jie Li ),( Ping He ),( Xingqi Lu ),( Yun Guo ),( Min Liu ),( Guoxiong Li ),( Jianping Ding ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.2
Background/Aims Depressive symptom is one of the most common symptoms in patients with irritable bowel syndrome (IBS), but its pathogenetic mechanisms remain unclear. As a voxel-level graph theory analysis method, degree centrality (DC) can provide a new perspective for exploring the abnormalities of whole-brain functional network of IBS with depressive symptoms (DEP-IBS). Methods DC, voxel-wise image and clinical symptoms correlation and seed-based functional connectivity (FC) analyses were performed in 28 DEP-IBS patients, 21 IBS without depressive symptoms (nDEP-IBS) patients and 36 matched healthy controls (HC) to reveal the abnormalities of whole brain FC in DEP-IBS. Results Compared to nDEP-IBS patients and HC, DEP-IBS patients showed significant decrease of DC in the left insula and increase of DC in the left precentral gyrus. The DC’s z-scores of the left insula negatively correlated with depression severity in DEP-IBS patients. Compared to nDEP-IBS patients, DEP-IBS patients showed increased left insula-related FC in the left inferior parietal lobule and right inferior occipital gyrus, and decreased left insula-related FC in the left precentral gyrus, right supplementary motor area (SMA), and postcentral gyrus. In DEP-IBS patients, abstracted clusters’ mean FC in the right SMA negatively correlated with depressive symptoms. Conclusions DEP-IBS patients have abnormal FC in brain regions associated with the fronto-limbic and sensorimotor networks, especially insula and SMA, which explains the vicious circle between negative emotion and gastrointestinal symptoms in IBS. Identification of such alterations may facilitate earlier and more accurate diagnosis of depression in IBS, and development of effective treatment strategies. (J Neurogastroenterol Motil 2021;27:248-256)