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1.
在混凝土结构温度及收缩作用计算中,结构的约束模型是关键.文章根据位移法推导了单层单跨框架、单层两跨框架、两层单跨框架以及根据变形协调条件推导了单块梁板等基本框架梁板结构的约束模型,并据此提出降低这种结构约束的措施:增加梁截面配筋,加大底层柱层高,采用分体柱,减小梁与板的截面面积比.  相似文献   

2.
利用边界元法与梁的挠度解析式耦合,分析边界(或内部)有梁文承的弹性支承板.首先对于薄板采用边界元法建立基本方程,而对于支承梁,则根据梁端的支座条件,采用相应的位移解析表达式.然后,根据板与支承梁之间的平衡和协调条件加以耦合,得到耦合方程.由耦合方程可解出未知参数,从而可进一步求解板或支承梁内任意点的位移和内力.  相似文献   

3.
空间框架—厚筏—土介质共同使用分析   总被引:2,自引:0,他引:2  
上部结构、筏基及地基之间是相互作用、相互影响的,本文揭示了结构物在满足静力平衡条件和变形协调条件的情况下,三部分之间的相互影响和内在联系,同时,本文采用考虑剪切变形的厚板理论来计算筏板基础,并将结果与薄板理论计算的结果作一比较,以考察薄板理论的适用范围及误差程度.  相似文献   

4.
将加劲板分为薄板和结合梁两部分,薄板部分用无奇点边界元法处理,而格栅用有限元法处理,分别建立各自的方程,然后根据板与梁之间的平衡和协调条件加以耦合,导出加劲板的自振特征方程,从而求解各阶频率和振型,本方法适于任意形状,任意边界条件的加劲板,且精度良好。  相似文献   

5.
将加劲极分为薄板和结合梁(格栅)两部分,薄板部分用无奇点边界元法(BEM)处理,而格栅用有限元法(FEM)处理,分别建立各自的方程,然后根据板与梁之间的平衡和协调条件加以耦合,导出加劲板的自振特征方程,从而求解各阶频率和振型.本方法适于任意形状、任意边界条件的加劲板,且精度良好.  相似文献   

6.
用边界元法(BEM)与有限元法(FEM)耦联分析曲(异)形桥加劲板,加劲板的薄板部分用BEM处理,而加劲梁(即格栅)用FEM处理,将两种方程根据板、梁之间的平衡和协调条件加以耦联,即可计算出有关未知参数,进而求解出板、梁的位移和内力.本方法可计算任意形状的桥面板,并适应任意布置的加劲梁.  相似文献   

7.
用无奇点边界元法处理弹性地基上的薄板;用有限元法处理加肋板上的肋梁(即格栅结构),根据弹性地基上的薄板与格栅之间的平衡与协调关系,将两种方法所建立的方程进行耦联,导出一组基本方程;求解板上选点的挠度和有关参数,进而求得板和肋梁的内力.本方法适于任意形状、多种边界条件以及不均匀地基上的加肋板.  相似文献   

8.
当前T梁、空心板以及等截面连续梁桥等的结构荷载试验比比皆是,要正确评定此类结构的承载能力,试验现场受条件的限制,准确测试梁的应变是困扰广大检测工程技术人员的难题.利用实测梁的变形来推算梁的应力方法可行,从理论上推导了简支梁、两端固结梁、两端固结梁、三跨连续梁分别在集中力、均布力的作用下的变形与应变关系式.利用某三跨等截面连续梁进行试验验证,第二跨实测与计算值应力与变形比分别为0.018 309、0.018 669,两者相差1.93%,第一跨、第三跨跨中应变和挠度比在0.018 750-0.019 607之间,与第二跨跨中的应变挠度比较为接近.推导变形与应变关系式可为T梁、空心板结构荷载试验的应变(动挠度)测量提供参考.  相似文献   

9.
钢筋混凝土宽柱双梁框架结构体系是旧房托换改造的一种新理念,由楼面板开孔浇筑托换梁混凝土,形成了新梁旧板叠合结构。基于有限元软件ABAQUS,对梁板叠合构件受剪承载力进行了数值模拟,研究了素混凝土浇筑孔个数对叠合构件整体性能的影响。模拟中采用三维实体建模,并从单元的选取、接触面的相互作用、材料本构的定义、荷载的施加等方面进行了较为系统地阐述。研究表明,有限元软件ABAQUS是分析叠合梁板构件受力性能的一种行之有效的工具;随着孔洞个数的增加,叠合的梁板趋于一整体,协调变形,共同工作,承载力逐渐增大,梁板叠合构件发生剪压破坏。  相似文献   

10.
从基础与地基变形协调条件出发,考虑地基梁的扭转影响,导出了地基梁的扭转刚度方程。能方便地求出任意长地基梁扭转引起的内力,为工程设计提供分析依据。  相似文献   

11.
提出的扇状梯形悬索屋盖结构,是又一新型悬索结构,特点是造型别致,易排水.本文应用非线性弹性理论,对此结构进行了有限元静力计算分析,并对各索单元张力采用均匀调整法进行调整,计算中还采用了协调调整法考虑悬索和圈梁的相互影响.锚固悬索的圈梁采用了双层空间框架结构形式,这种结构的优点是变形小,抗弯性能好等.  相似文献   

12.
深部复合顶板巷道变形破坏机理研究   总被引:1,自引:0,他引:1  
高应力下软弱复合顶板的持续塑性变形破坏,是深矿井巷道支护与维护的难点之一.分析了车集煤矿2405工作面区段运输平巷和区段回风平巷的围岩结构和岩性特征,构建了该类巷道复合顶板的力学模型,导出了该模型的力学变形方程.对巷道顶板变形破坏机理进行了深入分析,认为当巷道顶板岩层所受轴向压力大于岩梁达到屈服时的临界压力0.8倍时,巷道变形(下沉)明显增大,严重时产生冒顶.提出了同类巷道掘进过程中围岩控制的关键措施.  相似文献   

13.
To establish the movement relationship for the roof breaking under shallow mining conditions, the mechanical model of the roof rock beam was built, then the structure instability process of the roof rock beam was analyzed. The changing criterion of the vertical displacement was established and the relationship between the deflection and the rotary motion of roof block was determined. Regarding a mining face in Shangwan Mine, the responsing laws of the deflection and horizontal thrust of the roof rock beam were obtained through FLAC3D numerical analysis. The results show that the structure instability of the cracked roof rock beam depends on the interaction between the vertical load and the horizontal thrust.For the roof rock beam, when the vertical load keeps constant, the horizontal thrust fluctuating rises with increasing deflection. The horizontal thrust increases constantly with the deeper buried depth and the smaller span.  相似文献   

14.
In order to explore the pressure relief and structure stability mechanism of lateral cantilever structure in the stope under the direct coverage of thick hard roof and its impact on the gob-side entry retaining, a lateral cantilever fractured structural mechanical model was established on the basis of clarification for the stress environment of gob-side entry retaining, and the equation of roof given deformation and the balance judgment for fracture block were obtained. The optimal cantilever length was proposed based on the comparison of roof structural characteristics and the stress, deformation law of surrounding rocks under six different cantilever lengths by numerical simulation method. Double stress peaks exist on the sides of gob-side entry retaining and the entry located in the low stress area. The pressure of gob-side entry retaining can be relieved by reducing the cantilever length. However, due to the impact of arch structure of rock beam, unduly short cantilever would result in insufficient pressure relief and unduly long cantilever would bring larger roof stress which results in intense deformation. Therefore, there is optimal cantilever length, which was 7-8 m in this project that enables to achieve the minimum deformation and the most stabilized rock structure of entry retaining. An engineering case of gob-side entry retaining with the direct coverage of 10 m thick hard limestone roof was put forward, and the measured data verified the reasonability of conclusion.  相似文献   

15.
营口市奥体中心体育馆屋盖结构优化选型   总被引:1,自引:0,他引:1  
为得到营口市奥体中心比赛用馆屋盖结构的合理形式,基于通用有限元软件ANSYS及自主开发的辅助接口程序,对双层网壳及弦支网壳的两种结构形式进行了细致的受力分析,通过结构位移、支座反力、杆件内力及用钢量等参数的对比,确定了屋盖结构采用下层索在同一斜平面内的弦支网壳形式;同时对此结构形式进行更全面更具体的优化设计,从结构的总体变形、内力响应、用钢量等方面验证了此结构形式的合理性及可行性.  相似文献   

16.
办公楼等大跨装配式混凝土结构的强震响应很大程度上取决于楼/屋盖的连接结构构件性能、连接节点构造措施、以及由其控制的楼盖横隔板,应提出大跨装配式混凝土结构楼/屋盖及其连接构件的合理设计方法.基于线性参数化分析,考虑了9种板-板连接、5种墙-墙连接及3种板-墙/梁连接共135种不同刚度连接组合下模态分析,评价了节点连接刚度...  相似文献   

17.
Deep beam anchorage structures based on spatial distribution analysis of the cable prestressed field have been proposed for roadway roof support. Stability and other factors that influence deep beam structures are studied in this paper using mechanical calculations, numerical analysis and field measurements. A mechanical model of deep beam structure subjected to multiple loading is established, including analysis of roof support in the return airway of S1203 working face in the Yuwu coal mine, China. The expression of maximum shear stress in the deep beam structure is deduced according to the stress superposition criterion. It is found that the primary factors affecting deep beam structure stability are deep beam thickness, cable pre-tension and cable spacing. The variation of maximum shear stress distribution and prestressed field diffusion effects according to various factors are analyzed using Matlabòand FLAC3D~(TM) software, and practical support parameters of the S1203 return airway roof are determined.According to the observations of rock pressure, there is no evidence of roof separation, and the maximum values of roof subsidence and convergence of wall rock are 72 and 48 mm, respectively. The results show that the proposed roof support design with a deep beam structure is feasible and achieves effective control of the roadway roof.  相似文献   

18.
大倾角煤层采场顶板运动结构分析   总被引:21,自引:1,他引:21  
根据大倾角煤层采场矿压显现特点 ,对采场顶板岩层的运动、破坏形式进行了研究 .提出了大倾角条件下老顶岩层在运动中易于形成倾斜砌体结构板大结构 ,直接顶岩层则因上段冒落矸石充填 ,在采场中下段形成砌体梁小结构 ,并探讨了中下段小结构平衡的极限条件和结构失稳形式 .  相似文献   

19.
结合工程设计,对上翼铺设压型钢板屋面的蜂窝梁式檩条进行了试验。模拟实际屋盖结构,在压型钢板上施加均布荷载,分析了蜂窝梁式檩条的应力,计算模型,变形等计算公式。  相似文献   

20.
A series of plane-strain physical model experiments are carried out to study the spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway, which is subjected to the pressure induced by the mining process. The digital photogrammetry technology and large deformation analysis method are applied to measure the deformation and fracture of surrounding rocks. The experimental results indicate that the deformation and fracture of coal pillars are the cause to the instability and failure of the surrounding rocks. The spatiotemporal evolution rule of the rock deformation and fracture surrounding gob-side roadway is obtained. The coal pillar and the roof near coal pillar should be strengthened in support design. The engineering application results also can provide a useful guide that the combined support with wire meshes, beam, anchor bolt and cable is an effective method.  相似文献   

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