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1.
利用模态分析法基本原理对列车和桥梁,以及支墩进行动力学分析,阐述理论求解方法。运用无线传感器网络架构的监测系统对桥梁和支墩的加速度以及沉降进行了监测,在考虑静载荷加载的情况下,对比列车通过前后,支墩的沉降量的变化和桥梁与支墩加速度大小,得出支墩竖向受载荷后对桥梁振动影响并不显著,说明支墩的竖向刚度较大,竖向加载对其影响较小。研究支墩与桥梁的横向振动特性后,得出了由于支墩横向刚度远小于其竖向刚度,支墩与桥梁都表现出明显的响应特征。  相似文献   

2.
探讨如何确定镇墩向位移和镇支墩垂直位移的允许变形值和观测粘度指标问题,提出从管道伸缩节结构对镇支墩沉降差的实际承受能力出发计算管道镇支墩允许位移值及观测精度指标的理论,方法和公式。  相似文献   

3.
围绕全长7 373.921 m、主跨(110+220+220+110)m的榕江特大桥工艺复杂,技术标准高,施工难度大特点,在综合考虑工期、安全、质量、水文、地质等情况下,对榕江特大桥主跨钢桁梁施工采用临时支墩配合全回转架梁起重机对称悬拼,柔性拱施工采用全回转架梁起重机对称拼装方案。笔者对临时支墩进行了设计,并对临时支墩的稳定性进行了验算,满足了工程施工的需要,为同类桥梁的设计和施工积累了宝贵经验。  相似文献   

4.
预应力混凝土系杆拱桥由于竖拱以后,梁车运架不能正常通过,故在运架梁期间在箱梁跨中增加临时支墩,从而保证架桥机、运梁车等重型荷载能顺利通行。系杆拱上部结构拱肋、横梁要在运架梁完成后方可施工。设置临时支墩的施工方案在实际工程中得以成功运用,将对今后系杆拱施工工艺提供新的施工技术方案。  相似文献   

5.
混凝土的两种损伤模型及其应用   总被引:26,自引:0,他引:26  
本文首先用损伤力学的理论和实验相结合的方法,提出了两种描述混凝土损伤演变的模型——分段曲线模型和双线性模型.算例表明,利用这两种模型均能较好地描述混凝土的损伤特性.本文又将分段曲线模型推广到考虑温度影响的问题.并利用此模型用有限元方法计算和分析了柘溪单支墩大头坝表面裂缝的形成,计算结果和大头坝实际情况基本相符.  相似文献   

6.
结构非概率可靠性优化设计   总被引:7,自引:1,他引:7  
在结构质量限制条件下,提出了一个结构非概率可靠性设计的数学模型。数学模型由两个优化过程组成。第一个优化过程是在结构质量约束下极大化结构非概率可靠性。第二个优化过程是在载荷不确定性条件下,考虑结构应力,位移约束和极小化结构质量。其中第二个优化过程嵌套在第一个优化过程之中。作为一个数字算例。用所提出的优化模型进行了一个桁架结构的非概率可靠性优化设计。当关于所有不确定性载荷的信息严重缺乏时,设计者宜采用最小值最大化法则进行结构非概率可靠性优化设计,设计者如何仅对某个不确定性载荷的特性知之甚少而对其他不确定性载荷的波动变化有较好的了解,则可事先确定其他不确定性参数的值而最大化该不确定性参数。  相似文献   

7.
考虑了输入参数和荷载的有界不确定性,用区间变量来表示.将区间有限元分析同摄动方法、优化技术相结合,提出了求解区间有限元方程的区间参数摄动法和区间参数优化法,针对参数在较大范围内变化的情况,提出了参数分区求解的方法.通过数值算例进行了对比分析和讨论,说明了所提出方法的可行性和有效性.  相似文献   

8.
针对一种新型轨道式负刚度装置(negative stiffness device,NSD)提出了一种基于遗传算法的优化布置数学模型,该模型同时考虑NSD在加速度控制上的优势和位移控制上的劣势,设定5组加权系数组合,考察不同优化侧重下的控制效果.以某10层结构为算例,通过对比负刚度装置和传统阻尼器控制效果,得到最优加权系数组合;通过对比5组加权系数组合,得到负刚度装置优化布置基本原则.  相似文献   

9.
对一大型天文望远镜设备支墩建立了有限元分析模型,进行了自振频率计算.结合实测数据和一系 列计算模型,分析了边界支承条件和墩体配筋率对其自振频率的影响.指出对于此类支承于基岩上的设备 支墩,基础底板的锚固措施对其自振频率具有较大的影响;对于此类兼有弯曲和剪切变形特征的低矮悬臂 支墩,纵向配筋和横向配筋都可以提高其自振频率,但效果不显著.  相似文献   

10.
为提高发动机悬置系统的隔振性能,文章将稳健设计与多目标优化相结合,提出了一种发动机悬置系统多目标稳健优化方法。该方法采用第二代非劣排序遗传算法对悬置刚度进行确定性优化;考虑悬置刚度的不确定性,利用蒙特卡洛模拟方法获得确定性优化方案的可靠性,并利用6Sigma优化方法对悬置系统做了进一步稳健优化;最后以某型轿车的发动机悬置系统优化为例,验证了该方法的有效性。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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