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静态载荷下下前牙双端固定桥基牙牙周膜应力的三维有限元法分析
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作者 马达 唐亮 潘燕环 《暨南大学学报(自然科学与医学版)》 CAS CSCD 北大核心 2006年第4期586-587,590-591,共4页
目的:用三维有限元法分析静态载荷下,下颌前牙固定桥基牙牙周膜的应力和应变分布规律,为固定桥的设计和制作提供理论依据。方法:建立下颌前牙双端固定桥及其支持组织的三维有限元模型并进行静态条件下的垂直及斜向加载,计算基牙牙周膜... 目的:用三维有限元法分析静态载荷下,下颌前牙固定桥基牙牙周膜的应力和应变分布规律,为固定桥的设计和制作提供理论依据。方法:建立下颌前牙双端固定桥及其支持组织的三维有限元模型并进行静态条件下的垂直及斜向加载,计算基牙牙周膜的应力和应变值,绘出牙周膜的应力分布图。结果:固定桥修复前,垂直载荷下,基牙牙周膜的应力以压应力为主,应力集中在根尖;斜向载荷下,基牙牙周膜的应力主要是拉应力和压应力,应力集中在唇、舌颈缘;固定桥修复后,基牙牙周膜的应力和应变分布规律与修复前相似,但最大应力、应变值都明显增大;牙周膜内表面的应力大于牙周膜外表面;垂直载荷时,牙周膜内、外表面的应力差异更为显著。结论:固定桥的修复基本没有改变基牙牙周膜的应力和应变分布规律,但使上述值明显增大。牙周膜具有明显的应力缓冲作用,垂直载荷作用下的应力缓冲作用比斜向载荷作用下明显。 展开更多
关键词 牙周膜 静态载荷 垂直载荷 载荷
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斜向载荷下下颌KennedyⅠ类缺失冠外附着体义齿支持组织应力分析
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作者 牟雁东 樊瑜波 刘展 《中国实用口腔科杂志》 CAS 2009年第10期600-602,共3页
目的探讨斜向载荷下采用不同基牙数目时下颌后牙双侧游离缺损冠外附着体义齿支持组织的应力分布情况。方法2005年选取一成年健康男性志愿者的头部CT(取下颌牙槽骨部分)和离体尖牙、第一双尖牙、第二双尖牙、第一磨牙、第二磨牙的CT扫描... 目的探讨斜向载荷下采用不同基牙数目时下颌后牙双侧游离缺损冠外附着体义齿支持组织的应力分布情况。方法2005年选取一成年健康男性志愿者的头部CT(取下颌牙槽骨部分)和离体尖牙、第一双尖牙、第二双尖牙、第一磨牙、第二磨牙的CT扫描图片。建立下颌KennedyⅠ类牙列缺损冠外附着体义齿修复的三维有限元模型,分析在斜向载荷作用下采用不同基牙数目时,基牙牙周组织及缺牙区牙槽嵴的VonMises应力分布。结果斜向载荷下,末端基牙牙周膜应力集中区主要位于颊舌侧的牙颈部,随着基牙数目的增加,基牙牙周组织及缺牙区牙嵴的最大应力值都呈下降趋势,基牙由1颗增加至2颗时,应力明显下降,当基牙增加至3颗时,应力的下降量明显减少。结论在下颌游离缺损修复中,斜向载荷下冠外附着体义齿支持组织应力的减少与基牙数目的增加不完全成比例,在临床上应根据具体的情况确定联合基牙的数目。 展开更多
关键词 三维有限元 附着体义齿 载荷 应力分析
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Multi-objective optimization of multi-cell conical structures under dynamic loads 被引量:2
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作者 PIRMOHAMMAD Sadjad ESMAEILI-MARZDASHTI Sobhan 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第9期2464-2481,共18页
In this paper,crashworthiness performance of multi-cell conical tubes with new sectional configuration design(i.e.square,hexagonal,octagonal,decagon and circular)has been evaluated under axial and three different obli... In this paper,crashworthiness performance of multi-cell conical tubes with new sectional configuration design(i.e.square,hexagonal,octagonal,decagon and circular)has been evaluated under axial and three different oblique loads.The same weight conical tubes were comparatively studied using an experimentally validated finite element model generated in LS-DYNA.Complex proportional assessment(COPRAS)method was then employed to select the most efficient tube using two conflicting criteria,namely peak collapse force(PCF)and energy absorption(EA).From the COPRAS calculations,the multi-cell conical tube with decagonal cross-section(MCDT)showed the best crashworthiness performance.Furthermore,the effects of possible number of inside ribs on the crashworthiness of the decagonal conical tubes were also evaluated,and the results displayed that the tubes performed better as the number of ribs increased.Finally,parameters(the cone angle,θ,and ratio of the internal tube size to the external one,S)of MCDT were optimized by adopting artificial neural networks(ANN)and genetic algorithm(GA)techniques.Based on the multi-objective optimization results,the optimum dimension parameters were found to beθ=7.9o,S=0.46 andθ=8o,S=0.74 from the minimum distance selection(MDS)and COPRAS methods,respectively. 展开更多
关键词 CRASHWORTHINESS multi-cell conical tube axial and oblique loads complex proportional assessment(COPRAS) multi-objective optimization
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Crashworthiness of double-cell conical tubes with different cross sections subjected to dynamic axial and oblique loads 被引量:1
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作者 Pirmohammad Sadjad Ekbatan Mohammad-Hossein Esmaeili-Marzdashti Sobhan 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第3期632-645,共14页
Thin-walled tubes are increasingly used in automobile industries to improve structural safety.The present work deals with the collapse behavior of double-cell conical tubes subjected to dynamic axial and oblique loads... Thin-walled tubes are increasingly used in automobile industries to improve structural safety.The present work deals with the collapse behavior of double-cell conical tubes subjected to dynamic axial and oblique loads.Crashworthiness of these tubes having different sections(e.g.,circular,square,hexagonal,octagonal,decagonal)was numerically investigated by using an experimentally validated finite element model generated in LS-DYNA.Geometry of these tubes was then optimized by decreasing the cross section dimensions at the distal end while the weight remained unchanged.Octagonal conical tube was finally found to be more preferable to the others as a collision energy absorber.In addition,square and circular tubes showed diamond deformation mode,while the other tubes collapsed in concertina mode.A decision making method called TOPSIS was finally implemented on the numerical results to select the most efficient energy absorber. 展开更多
关键词 CRASHWORTHINESS dynamic axial and oblique load double-cell conical tube mean dynamic load
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