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本文给出了文献[1]认为无法找到的应力函数,求出了厚壁圆筒在二次分布压力下的弹性理论解。所导出的广义拉梅公式具有更广范的使用范围,不仅可以解释拉梅公式使用不当所引起的偏差,对有关工程问题的设计和计算也有参考价值 相似文献
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CFRP布加固木梁界面粘结应力的试验研究和理论分析 总被引:1,自引:0,他引:1
为了研究CFRP布加固木梁的界面粘结应力,对6根CFRP布加固的木梁进行了静力试验,得到了碳纤维布端部的应变分布。由相邻两测点的应变计算出了CFRP布与木材的平均界面粘结剪应力。忽略碳纤维布和木梁的剪切变形,推导了在任意荷载作用下两者之间的界面粘结剪应力和粘结正应力的计算公式,并根据边界条件给出了在两点对称集中荷载作用下公式中的系数,应用该公式计算了试验梁碳纤维布端部的界面粘结剪应力和正应力,结果表明粘结剪应力的计算值与试验值吻合较好,说明该公式是可行的。 相似文献
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结合工程实测,模拟分析了大型基础下层状砂土地基基底有效附加应力、基础内钢筋应力以及基底竖向变形的变化过程与分布规律。研究结果表明,受基坑降水影响,基底上覆土层有效应力增量对基底沉降的贡献不可忽略;基底压应力不能简单假设为均布荷载,基底最大应力作用点不一定就是最大沉降发生点;基底平面上沉降分布不均匀,基础中心点处的沉降也不一定最大;施工加载期间,基础内钢筋应力呈现交变状态,但钢筋强度发挥有限,仅为其屈服强度的25%;砂土沉降计算经验系数随土层变形模量的增大而减小,但减小幅度不显著。研究结论可为层状砂土地基及其上大型基础设计提供直接参考依据。 相似文献
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三向应力状态下地基最终沉降量计算方法的探讨 总被引:2,自引:0,他引:2
本文给出了半空间弹性体表面在竖向分布荷载作用下,考虑三向应力状态时的地基最终沉降量的数值计算方法和计算程序,能够快速方便地计算出地基沉降曲线。并以实例分析了影响地基最终沉降量的因素,其结论对今后地基基础工程具有实际意义。 相似文献
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利用ANSYS数值分析软件,首先讨论了不同半椭球体初级蚀坑深宽比对应力分布及应力集中系数的影响,得到了单调拉伸荷载作用下半椭球体蚀坑应力集中系数Kt计算模型。然后以半椭球体蚀坑为基准,通过改变蚀坑宽度或长度,建立了具有不同三维尺寸蚀坑钢材模型,分析了蚀坑宽度或长度变化对应力集中系数的影响规律,得到了单调拉伸荷载作用下蚀坑宽度或长度变化时Kt近似计算模型。最后讨论了次级蚀坑三维变化对应力集中系数的影响规律。 相似文献
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根据Muskhelishvili的复势理论,结合裂面边界条件和位移单值条件,将无限大平面受压应力作用的裂纹问题转化为对应的Hilbert问题,并运用复变函数法分别给出了在伪集中力作用下,不同裂面形态的基本解。对不同裂面形态的摩擦力大小和分布进行了详细分析,建立了新的摩擦力计算模型。采用“伪力法”和叠加原理,结合所求的基本解,给出了含中心斜裂纹的岩石类材料在压缩荷载作用下的应力强度因子(SIF)的解法。研究表明:裂面状态对KⅠ的大小没有影响,而对KⅡ的影响却很大,相同应力条件下,裂面状态会影响裂纹的开裂角和开裂方式。 相似文献
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基于文献试验,建立了土工防爆墙倾覆稳定计算方法。假设墙体在水平均布冲击波荷载作用下绕墙趾产生刚体转动,分别得到了指数衰减荷载和瞬时冲量荷载作用下墙体转动线性微分方程的解析解和倾覆稳定系数计算公式,并采用Rung-Kutta法求解墙体转动非线性微分方程和倾覆稳定系数的数值解。对于文献中的两种土工防爆墙,解析解、数值解与试验结果比较表明:理论计算与试验结果吻合较好;可忽略冲击波加载时程和墙体转动微分方程非线性对倾覆稳定系数的影响,按瞬时冲量荷载下的解析解计算倾覆稳定系数,并取容许倾覆稳定系数为1.1。 相似文献
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对正弯矩区组合梁腹板局部稳定性进行研究,首先要建立板件在拉、弯、剪共同作用下的相关屈曲方程。该文在前人研究的基础上,根据能量方法研究了四边简支板件在拉、弯、剪共同作用下的弹性相关屈曲方程,并利用通用有限元软件ANSYS建模进行计算,验证了理论推导结果,最终提出简化公式。随后在相关方程的基础上,推导出相应的弹性高厚比限值。并将该限值与未考虑弯拉作用的限值进行对比,结果有明显提高,多数情况下可放宽26%以上。该文成果为进一步研究正弯矩区组合梁腹板考虑残余应力和初始缺陷的弹塑性屈曲提供基 础。 相似文献
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Jie Zhang Zheng Liang Chuanjun Han 《International Journal of Pavement Engineering》2017,18(7):608-621
Numerical simulation model of buried pipeline crossing ground settlement zone was established considering pipeline–soil interaction. Mechanical behaviour of the buried pipeline was investigated, and effects of ground settlement, pipeline parameters and surrounding soil parameters on mechanical behaviour of the buried pipeline were discussed. These results show that there are two high stress areas on both sides of the dividing plane. High stress areas are oval on the top and bottom of the pipeline. Z-shape bending deformation appears under the action of ground settlement. In ground settlement zone, axial strain on the top of the pipeline is compression strain, and axial strain on the bottom of the pipeline is tension strain. On the contrary, they are tension strain and compression strain respectively in no settlement zone. Bending deformation, axial strain and plastic strain of the buried pipeline increase with the increase in ground settlement. Von Mises stress, high stress area, axial strain and plastic strain of the buried pipeline increase with the increasing diameter-thick ratio and internal pressure, but they decrease with the increase in buried depth. Diameter-thick ratio and internal pressure have a small effect on the bending deformation of the buried pipeline. Bending deformation decreases with the increase in buried depth in ground settlement zone. Von Mises stress and high stress area increase with the increasing surrounding soil’s elasticity modulus and cohesion, but they increase first and then decrease with the increase in Poisson’s ratio. Bending deformation of the pipeline in no settlement zone increases with the increase in elasticity modulus and Poisson’s ratio, but it is affected little by the cohesion. Axial strain and plastic strain have a bigger relationship with the elasticity modulus and Poisson’s ratio. Axial strain and plastic strain of the buried pipeline increase with the increase in cohesion, and the change rates increase with the increase in ground settlement. 相似文献
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Stress intensity factor for a cracked specimen under compression 总被引:1,自引:0,他引:1
For a cracked specimen under compression, a set of complex stress functions is proposed and by using the boundary collocation method, the unknown coefficients of these complex stress functions are determined. Based on the calculation results of the boundary collocation method, the formulas of the stress intensity factor for a cracked specimen under compression are obtained, and by using these formulas, the influence of confining stress on stress intensity factor is analyzed. 相似文献
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基于双轴拉伸载荷下复合材料十字型试样的设计特点,对比分析了不同几何形状的十字型试样在不同厚度比和载荷比条件下中心测试区应力集中系数和承力系数的变化规律,并开展了不同载荷比的双轴拉伸实验进行验证。研究表明:十字型试样中心测试区系数与载荷大小无关,与试样几何形状、厚度比及载荷比有关;等宽加载臂宽度越小、厚度比越大,应力集中系数越小,载荷比不同,应力集中系数也不同;一般而言,中心测试区承力系数随厚度比增加而增大,x向承力系数βx随载荷比增加呈非线性增大,y向承力系数βy随载荷比增加呈线性减小;在双轴拉伸载荷条件下,形状D十字型试样在载荷比f=4/1时中心测试区y向应力分量为负值,表现为压应力状态。 相似文献
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This article, based on first-order shear deformation theory, presents the buckling analysis of a rotationally restrained orthotropic rectangular Mindlin plate resting on a Pasternak elastic foundation. Thus, the Mindlin–Reissner plate theory is employed for which the governing equations are solved by the Rayleigh–Ritz method. Uniformly distributed in-plane loads are applied to two simply supported opposite edges of the plate and the other two edges have rotationally restrained conditions without loading. Finally, the effects of plate parameters, such as foundation stiffness coefficients, aspect ratios, and ratio of elastic modulus in the x to y direction on the buckling loads are presented. The results show that the buckling load would increase when the ratio of the elastic modulus in the x to y direction increases and the plate is close to isotropic. The variation of buckling load versus changing ratio of elastic modulus in the x to y direction in the state of without elastic foundation and with clamp support is more than the rest of the state. 相似文献
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The stress intensity factor is a traditional topic in mechanics and there have been many solutions for many different cases. The closed frictional crack problem has been modeled in the rock mechanics field where fractures are mostly under compression. Further, the effect of finite plate dimensions under biaxial loading has not been considered in the literature. The key contribution of the present paper is to evaluate the effect of the crack length to plate width ratio on the mode I and II stress intensity factors (SIF) of a central slant crack with frictional surfaces in plates with biaxial loading of different patterns, i.e. tension-tension, tension-compression, compression-tension or compression-compression. A plane strain elastic two-dimensional finite element analysis was adopted. Crack length to plate width ratios equal to 0.1, 0.3 and 0.5 with biaxial ratios from –1 to 1, crack angles from 0° to 90° and friction coefficients from 0 to 1 were considered. Contact regimes and the effect of the crack length to plate width ratio were found dependent on biaxial ratio and pattern, friction coefficient and crack angle. 相似文献
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X形桩是一种具有反拱曲面的新型异形桩,该文以半无限体内受竖向集中力作用的Mindlin应力解为依据,通过沿X形桩桩周8个积分区间线积分,再沿桩长进行积分,得到了X形桩侧摩阻力沿桩身线性增长、沿桩周均匀分布、沿桩身矩形分布、沿桩周均匀分布侧摩阻力产生竖向附加应力系数的数值计算方法。通过沿X形桩截面3个积分区间面积积分,得到了X形桩均布端阻力在地基内产生竖向附加应力系数的数值计算方法。X形桩侧摩阻力和端阻力产生附加应力系数均随着外包方形截面边长和开弧间距增大而减小,随弧度数增大而增大。同周长X形桩侧摩阻力产生附加应力系数大于圆形桩,周长越大差别越大;同面积X形桩端阻力产生附加应力系数小于圆形桩,面积越大差别越大。 相似文献