共查询到20条相似文献,搜索用时 804 毫秒
1.
《应用数学和力学》2020,(5)
考虑混凝土顶板和钢底板不同的模量,结合变分法推导了波形钢腹板-钢底板-混凝土顶板(CSWSBCT)组合箱梁剪力滞效应的控制微分方程组和边界条件,建立了CSWSBCT两跨连续箱梁跨中集中荷载、均布荷载作用下剪力滞系数的计算公式,采用模型试验梁对两种荷载工况下连续组合箱梁的剪力滞效应进行了分析.结果表明:其理论计算值与模型试验实测值和有限元值在波形钢腹板的顶底板上三者吻合较好,变化趋势一致,验证了计算公式的正确性;均布荷载作用下中间支点截面处顶底板的剪力滞系数最大值大于集中荷载工况下最大值,且在两种荷载工况下中间支点截面处波形钢腹板和混凝土顶板、钢底板交界处的剪力滞效应突出. 相似文献
2.
非线性边界滑移挤压膜流动 总被引:1,自引:0,他引:1
用一种包含初始滑移长度和临界剪切率的非线性边界滑移模型研究了两个球体间的挤压流体膜问题.研究发现初始滑移长度对低剪切率下的滑移行为起主要作用,而临界剪切率决定了高剪切率下的边界滑移程度.球体表面挤压流体膜的边界滑移量是与半径坐标相关的高度非线性函数.在挤压膜的中心点和远离中心点处由于低剪切率滑移量等于初始滑移长度,然而在高剪切率区域滑移长度迅速增加.球体挤压膜的流体动压力随着初始滑移长度的增加和临界剪切率的减小而减小,并且临界剪切率对流体动力的影响要比初始滑移长度大的多,当临界剪切率很小的情况下,流体动压随着最小膜厚的减小几乎不再增加.所用模型给出的理论预报和实验非常吻合. 相似文献
3.
4.
5.
建筑结构可靠性设计的半随机过程模型 总被引:3,自引:0,他引:3
本文讨论抗力随机变量R、荷载效应随机过程S(t)的工程结构可靠性设计模型。在一些实际上容易满足的条件下,给出了便于实际应用的抗力和荷载分项安全系数的计算公式。 相似文献
6.
界面滑移流体动压膜承载能力的形成 总被引:1,自引:0,他引:1
运用界面滑移可在两平行平板表面间形成具有承载能力的流体动压膜.在流体入口区,静止平板表面上流体-接触表面的界面剪切强度具有较低值,以在该界面处产生界面滑移,而在流体出口区,静止平板表面上流体-接触表面的界面剪切强度具有足够高的值,以避免在该界面处出现界面滑移.整个运动平板表面上流体-接触表面的界面剪切强度具有足够高的值,以避免在运动平板表面上出现界面滑移.分析表明,这种流体动压接触区具有显著承载能力.使整个接触区具有最大承载能力的流体出口区宽度与入口区宽度的比值为0.5. 相似文献
7.
基于Reddy高阶剪切变形理论的Kármám-Donnell型非线性壳体方程,给出复合材料层合剪切圆柱曲板在侧压作用下的后屈曲分析。将壳体屈曲的边界层理论推广到复合材料层合剪切圆柱曲板受侧压作用的情况。相应的奇异摄动法,用于确定圆柱曲板的屈曲荷载和后屈曲平衡路径。分析中同时考虑非线性前屈曲变形和初始几何缺陷的影响。数值算例给出完善和非完善,中等厚度正交铺设层合圆柱曲板的后屈曲荷载-挠度曲线。讨论了横向剪切变形,曲板几何参数,铺层数,铺展方式和初始几何缺陷等各种参数变化的影响。 相似文献
8.
针对目前钢拉杆构件缺少施工荷载下的内力测试和服役期间的长期监测手段问题,采用玻璃钢封装技术研制开发出一种新型的基于光纤光栅绝对测量传感技术的高耐久性智能钢拉杆。在理论屈服荷载85%的拉伸荷载下,智能钢拉杆感知的应变具有很好的线性度和重复性,由其得到的测试杆力与实验张拉力吻合良好,误差在4%以内。该智能钢拉杆具有抗电磁干扰、传感距离长、成本低、耐腐蚀、绝对测量等优点,既可以方便给出任何阶段的受力状态,也可以作为一个大应变式荷载传感器对其相邻的结构进行荷载监测,适合用于恶劣服役环境下的钢拉杆工程结构。 相似文献
9.
讨论有限变形和小变形假设下本构关系的区别,并将其运用于混凝土的弹-粘塑性本构关系研究,提出了一个应变率相关的动态力学模型.模型基于Ottosen的4参数屈服准则,分别考虑混凝土在硬化阶段和软化阶段加载面的不同变化规律,建立冲击荷载下的混凝土本构关系.该模型可以应用于冲击载荷下混凝土材料响应的模拟.引进Green-Naghdi客观率建立有限变形的混凝土模型.根据大量实验结果对应变率和材料强度的关系提出合理假设,使模型可以反映混凝土大变形的动态力学行为,为相关工程问题的研究提供有益的思路和有效的工具. 相似文献
10.
11.
A simple procedure is proposed for the assessment of reinforced rectangular concrete columns under combined biaxial bending
and axial loads and for the design of a correct amount of FRP-strengthening for underdesigned concrete sections. Approximate
closed-form equations are developed based on the load contour method originally proposed by Bresler for reinforced concrete
sections. The 3D failure surface is approximated along its contours, at a constant axial load, by means of equations given
as the sum of the acting/resisting moment ratio in the directions of principal axes of the sections, raised to a power depending
on the axial load, the steel reinforcement ratio, and the section shape. The method is extended to FRP-strengthened sections.
Moreover, to make it possible to apply the load contour method in a more practical way, simple closed-form equations are developed
for rectangular reinforced concrete sections with a two-way steel reinforcement and FRP strengthenings on each side. A comparison
between the approach proposed and the fiber method (which is considered exact) shows that the simplified equations correctly
represent the section interaction diagram.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 3, pp. 443–462, May–June, 2008. 相似文献
12.
本文首次将文献[1]所提出的线载荷积分方程法应用于求解弹性动力学问题。导出了刚性基础上的弹性层在表面垂直集中简谐载荷作用下动力响应问题的一维非奇异积分方程组,并求得了数值解。 相似文献
13.
Experimental Study on the Flexural Ductility of BFRP Bar Concrete Beams With Bamboo Fiber and Steel Wire Mesh北大核心CSCD 下载免费PDF全文
To study the effects of bamboo fiber and steel wire mesh on the flexural ductility of basalt fiber reinforced polymer(BFRP)bar concrete beams, 7 BFRP bar concrete beams with bamboo fiber and steel wire mesh were tested with different bamboo fiber lengths (0 mm, 30 mm and 45 mm) and different steel wire mesh layout ranges (0, 1/2 maximum bending moment point layout and full beam length layout). The flexural failure tests of the 7 beams were carried out, and the initial crack loads, the crack developments, the ultimate loads and the deformations were detected. The effects of the fiber length and the wire mesh layout range on the crack resistance and the deformation resistance of the specimens were analyzed based on the test data. With the function model, the equivalent yield points of the 7 test beams were obtained, and their ductility coefficients were calculated. The results show that, the addition of bamboo fiber and steel wire mesh increases the cracking loads of BFRP bar concrete beams by 12%~68%, decreases the crack spacings and the crack length development speed, reduces the test beam deformation under the same load, and increases the ductility coefficient by 1.58%~31.75%. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved. 相似文献
14.
15.
本文讨论闭合圆柱形壳体在冲击荷载作用下的动力计算.文中分析冲击过程各阶段的动量及能量的变化,并计入冲击物和被冲击的闭合圆柱壳系统质量的影响;用相当质量法将整个圆柱形壳体的分布质量转化为只有一个集中的“相当质量”,从而导出闭合圆柱形壳体在冲击力作用下的动力因数.本文的特点是具有实用价值,计算比较简便. 相似文献
16.
17.
本文用能量法研究悬臂矩形板侧向屈曲中的几个问题.文中分别讨论了有集中力,均布荷载,三角形分布荷载及集中力偶作用之下悬臂矩形板发生侧向屈曲时的最小临界荷载. 相似文献
18.
19.
本文用能量法研究了矩形板不对称侧向屈曲的几个问题,文中讨论了具有不对称支承的矩形板分别在有集中力,均布荷载及集中力偶作用之下发生不对称侧向屈曲时的最小的临界荷载. 相似文献
20.
Dynamic Green's function plays an important role in the study of various wave radiation, scattering and soil-structure interaction problems. However, little research has been done on the response of transversely isotropic saturated layered media. In this paper, the 3D dynamic responses of a multi-layered transversely isotropic saturated half-space subjected to concentrated forces and pore pressure are investigated. First, utilizing Fourier expansion in circumferential direction accompanied by Hankel integral transform in radial direction, the wave equations for transversely isotropic saturated medium in cylindrical coordinate system are solved. Next, with the aid of the exact dynamic stiffness matrix for in-plane and out-of-plane motions, the solutions for multi-layered transversely isotropic saturated half-space under concentrated forces and pore pressure are obtained by direct stiffness method. A FORTRAN computer code is developed to achieve numerical evaluation of the proposed method, and its accuracy is validated through comparison with existing solutions that are special cases of the more general problems addressed. In addition, selected numerical results for a homogeneous and a layered material model are performed to illustrate the effects of material anisotropy, load frequency, drainage condition and layering on the dynamic responses. The presented solutions form a complete set of Green's functions for concentrated forces (including horizontal load in x(y)-direction, vertical load in z-direction) as well as pore pressure, which lays the foundation for further exploring wave propagation of complex local site in a layered transversely isotropic saturated half-space by using the BEMs. 相似文献