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轴向载荷下多平面DT型管节点应力集中系数研究 被引量:1
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作者 袁奎霖 杨海天 洪明 《船舶力学》 EI CSCD 北大核心 2019年第4期476-487,共12页
应力集中系数对于海洋平台结构中管节点的疲劳寿命评估至关重要。文章以多平面DT型管节点为研究对象,采用有限元方法分析了轴向载荷作用下沿其弦管—撑管相贯线焊缝的应力集中系数分布。在保证计算精度的前提下尽量减少网格数量,采用分... 应力集中系数对于海洋平台结构中管节点的疲劳寿命评估至关重要。文章以多平面DT型管节点为研究对象,采用有限元方法分析了轴向载荷作用下沿其弦管—撑管相贯线焊缝的应力集中系数分布。在保证计算精度的前提下尽量减少网格数量,采用分区网格划分方法进行管节点建模。基于有限元分析结果,研究了不同几何形状参数对应力集中系数分布变化规律的影响,拟合得到一组应力集中系数参数公式,并通过两种相对误差验证了该参数公式的有效性。 展开更多
关键词 应力集中系数 多平面DT型管节点 轴向载荷 参数方程
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轴向载荷下多平面DT型管节点应力集中系数概率模型研究(英文) 被引量:3
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作者 袁奎霖 姜永一 +1 位作者 杨海天 洪明 《船舶力学》 EI CSCD 北大核心 2018年第6期758-770,共13页
应力集中系数作为一个随机变量,对管节点及导管架平台的疲劳可靠性评估结果有着重要影响。文章以多平面DT型管节点为研究对象,建立了352个几何参数不同的三维管节点有限元模型,并分析了沿弦管-撑管焊缝处的应力集中系数分布。采用密度... 应力集中系数作为一个随机变量,对管节点及导管架平台的疲劳可靠性评估结果有着重要影响。文章以多平面DT型管节点为研究对象,建立了352个几何参数不同的三维管节点有限元模型,并分析了沿弦管-撑管焊缝处的应力集中系数分布。采用密度直方图描述最大应力集中系数统计样本的特征,利用疲劳可靠性分析中常用的几种概率分布进行拟合。各个概率模型中的参数通过极大似然估计方法得到。根据卡方检验的结果对比发现,Birnbaum-Saunders分布是最适合的概率模型。因此,文中提出一组适用于描述在轴向载荷即单向轴向和平衡轴向载荷作用下多平面DT型管节点弦管侧和撑管侧最大应力集中系数分布的概率模型,对今后导管架式海洋平台结构的疲劳可靠性分析具有重要意义。 展开更多
关键词 应力集中系数 多平面DT型管节点 轴向载荷 概率密度函数
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Value of section plane,MPR,and 3D-CTVR techniques in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane 被引量:6
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作者 Yang Liu Feng Yang +1 位作者 QiaoHui Lu Danheng Zhao 《Journal of Otology》 CSCD 2017年第2期80-85,共6页
Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ... Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.Methods: Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals,intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.Results: MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations(P > 0.05).Conclusion: CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation. 展开更多
关键词 Ossicular chain Conductive hearing loss Volume rendered computer tomography multi-planar REFORMATION SECTION pla
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Application of the multi-planar reconstruction in endovascular treatment of type B aortic dissection 被引量:1
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作者 LI Yong-sheng HOU Kai +6 位作者 XU Xin YANG Jue ZHU Ting DONG Zhi-hui YUE Jia-ning WANG Yu—qi FU Wei-guo 《Chinese Medical Journal》 SCIE CAS CSCD 2013年第23期4499-4503,共5页
Background Although Multi-planar reconstruction (MPR) has been considered a diagnostic imaging technique that observes more perspectives for diseases,few people have applied it surgically.In fact,MPR is also very us... Background Although Multi-planar reconstruction (MPR) has been considered a diagnostic imaging technique that observes more perspectives for diseases,few people have applied it surgically.In fact,MPR is also very useful to clinical operation,especially for patients with type B aortic dissection.It helps the surgeon to locate accurately with more information about aortic dissection,so that the safety and effectiveness of operation can be improved.This study examined the application of the MPR in intraoperative DSA imaging for precise positioning by accurately obtaining a crosssection,a spin angle of the coronal plane,and a tilt angle of the sagittal plane in treatment of type B aortic dissection.Methods The conventional and the MPR approaches were compared on positioning the aortic arch for surgery.A group of 40 patients (group A) and another group of 42 patients (group B) was sampled.About the comparison of baseline characteristics,a fourfold table X2 test was conducted on gender,and two independent samples t-test was applied to age between group A and group B.Spin as well as tilt angles for group A were obtained from the patients using both approaches,and their effectiveness was compared with pair t-tests; The MPR data guided stent-grafting in this group.Stent graft placement of group B was based on the conventional approach.Percentages of proximal distributed markers as well as incidences of complications were collected from both groups after stent graft placement.They were also compared with a fourfold table X2 test.Results Gender difference was not found between group A and group B (X2=0.80,P >0.05),and age difference was not statistically significant (F=2.55,homogeneity of variance,t=-1.46,P >0.05).A significant difference was found between the conventional and the MPR approaches for spin angle (t=9.17) as well as tilt angle (t=-2.07),P <0.05.Percentage of proximal distributed markers (5.0%) of group A was significantly lower than that of group B (42.9%),X2=15.92,P <0.05;and incidence of complications (5.0%) of group A was also significant lower than that of group B (21.4%),X2=4.76,P <0.05.Conclusions Application of the MPR facilitated intraoperative angle adaption and led to satisfactory DSA.It is feasible in endovascular treatment of type B aortic dissection,and can effectively and safely guide surgical operations. 展开更多
关键词 multi-planar reconstruction thoracic endovascular aortic repair spin angle tilt angle
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