弹性地基上的自由边矩形板

本文讨论了在弹性地基上的自由边矩形板的弯曲问题.我们讨论了两种情形,诸如在板的中心受到一集中力作用和在板的四个角点上各受到一相等的集中力作用.文中选择了一个挠曲函数,它不但能满足所有自由边上的全部几何边界条件,而且也满足所有的内力边界条件.同时,我们应用了变分法,从而得到了较好的近似解答.     

聚丙烯纤维与废胶粉混杂砼抗拉抗折性能研究

本文通过对28天龄期的废旧轮胎胶粉与聚丙烯纤维混杂混凝土的抗拉、抗折强度等力学性能试验研究,得出初步结论：混杂混凝土,比相同掺量的单一胶粉混凝土的抗拉、抗折性能有所提高,并具有极好的强度恢复性能。混杂混凝土抗折强度掺量为5%时强度最大,10%时又出现下降趋势。     

钢骨混凝土梁正截面抗弯承载力的计算与分析

根据国内外钢骨混凝土梁正截面抗弯承载力的计算方法,结合具体实例本文分析了这些计算方法的优缺点,并提出了建议。     

UHPC预制拼装综合管廊的抗弯性能试验

针对预制拼装RC管廊自重大和吊装难的问题,通过试设计UHPC预制拼装管廊主体构造,并进行1:2模型的静力试验,得到了各级荷载作用下UHPC综合管廊的顶板、底板和侧墙的破坏形态、荷载-变形关系、钢筋和混凝土应变,并对整体受力机制、破坏模式和极限承载力进行了分析。结果表明,UHPC管廊重量可减少30%,破坏模式与RC管廊基本一致,均为弯曲破坏,但UHPC管廊的开裂荷载和变形能力明显提高。在实测数据的基础上,通过简化拉压区应力分布图形,建立UHPC综合管廊抗弯极限承载力的计算方法,得到的计算值与实测值吻合良好,误差在10%左右。提出的计算公式可为UHPC综合管廊的设计计算提供参考。     

固体材料拉伸波速的共振法测量

文章系统论述了利用弯曲共振和纵向共振两种方式测量拉伸波速的方法，作者改进了传统的纵向共振测试装置，指出了两种方式各自的适用性．在理论上纵向共振方法更为严谨，且误差来源较少，从而具有较高测量精度，实验上测量操作更为方便．     

黏性介质中圆截面弹性细杆的平面振动

讨论圆截面弹性细杆在黏性介质中的平面振动. 基于Kirchhoff理论，以杆中心线的Frenet坐标系为参考系，建立其动力学方程，杆中心线为任意平面曲线时，其扭转振动与弯曲振动解耦. 讨论两端固定条件下任意形状杆的平面扭转振动，以及无扭转的轴向受压直杆和圆环杆的平面弯曲振动，导出其自由振动频率和阻尼系数. 证明空间域内压杆的Lyapunov稳定性和欧拉稳定性条件为时域内渐近稳定性的充分必要条件，或无阻尼压杆的稳定性必要条件. 圆环杆平衡恒满足渐近稳定性条件. 关键词： 弹性细杆 黏性介质 扭转振动 弯曲振动     

Research in the flexural buckling modes of a cylindrical sandwich shell under the action of a temperature field inhomogeneous across its thickness

A solution to the problem on the stability according to the flexural buckling mode is given for a cylindrical sandwich shell with a transversely soft core of arbitrary thickness. The shell is under the action of a temperature field inhomogeneous across the thickness, and its end faces are fastened in such a way (in the axial direction, the face sections of the external layer are fixed, but of the internal one are free) that an inhomogeneous subcritical stress-strain state arises in the shell across the thickness of its layers. It is shown that, under such conditions, the buckling mode of the shell is mixed flexural. To reveal and investigate this mode, equations of subcritical equilibrium and stability of a corresponding degree of accuracy are needed.Translated from Mekhanika Kompozitnykh Materialov, Vol. 40, No. 6, pp. 715–730, November–December, 2004.     

预应力FRP加固混凝土梁性能研究

通过数值计算和试验，对外贴预应力FRP加固受弯构件的受力性能进行了研究，对加固后钢筋混凝土梁正截面的破坏特征、受力特点和影响因素以及构件变形进行分析。结果表明，计算数据与实验数据具有较好的吻合度，同时分析了造成实验数据和计算数据误差的原．因，为加固设计和计算提供必要的参考。     

Macromechanical Characteristics Deduced from Three-Point Flexure Tests on Unidirectional Carbon/Epoxy Composites

Effects of different factors on the measured values of flexural modulus and flexural strength of unidirectional carbon/epoxy composites are investigated. This allows a correct interpretation of the results of flexural macromechanical properties obtained in three-point flexure tests. The shear deformation, the displacement of neutral axis from the mid-depth of the beam, and the nonuniform distribution of stresses in bent coupons are discussed.     

Flexural motion in laser evaporative heated cantilever workpiece: Three-dimensional analysis

Laser evaporative heating of metallic surfaces generates a recoil pressure at liquid–vapor interface. Since the magnitude of recoil pressure is considerably high, despite the small evaporative area, the pressure force generated normal to the workpiece surface is considerably high. Consequently, pressure force initiates a flexural motion of the workpiece subjected to a laser evaporative heating. In the present study, flexural motion of a steel plate, with a cantilever arrangement, due to laser evaporative heating is considered. Stress field in the workpiece is also taken into account. Three-dimensional motion of the workpiece is modeled and governing equations of motion and stress field are solved numerically using the finite element method. It is found that surface displacement in the order of 20 m is predicted and the maximum equivalent stress in the order of 700 kPa is obtained. Additional copper element in the workpiece alters the temporal variation of stress levels.