大跨径斜拉桥无应力线形的研究

文章分析了桥梁结构非线性软件Nlabs与大型有限元分析软件Ansys的计算结果,提出得到悬臂拼装斜拉桥无应力线形的方法,利用此方法分别得到某千米跨径斜拉桥主桥的无应力线形,通过讨论两者的一致性,进而说明采用Nlabs对大跨径斜拉桥进行施工控制的可行性和合理性。     

不锈钢基体激光熔覆Ni60A的残余应力研究

选择激光功率、扫描速度、送粉量为影响因素,用正交试验方法研究了不锈钢基体激光熔覆Ni60A的残余应力;结果表明:影响残余应力的关键因素为扫描速度,其次是激光功率,最后为送粉量;扫描速度180 mm/min、激光功率1.5 kW、送粉量3 g/s产生最小残余应力;此时熔覆材料Ni60A与基体形成良好的冶金结合,熔覆层组织均匀,无微裂纹等明显缺陷。研究结果为叶轮和螺杆的激光熔覆再制造提供了实验依据。     

河道型水库蓄水诱发地震的数值模拟

利用二维弹性有限元模型,计算了河道型水库蓄水造成的地应力变化,进而计算了走向平行于水库长轴的不同倾角断层面上库仑应力变化,以此来评价水库蓄水对库区断层稳定性的影响.结果表明,蓄水增加的压应力非常有限;如果背景应力场有利于正断层活动,蓄水可能会导致一定深度和倾角的断层更加危险;如果背景应力场有利于浅表的逆断层活动,蓄水会抑制不同倾角的逆断层活动.     

喷丸强化在模具表面处理中的应用

喷丸强化是一种经济、简便而有效的模具表面处理工艺方法,本文对喷丸强化的原理、工艺及应用做了较详尽的阐述。     

Theoretical study on constitutive relationship of fiber reinforced polymer confined concrete

We proposed a bilinearity constitutive curve model of fiber reinforced polymer （FRP） confined concrete which includes a parabola in the first stage and a straight line in the second stage. The FRP-confined concrete has powerful confinement status and weak confinement status leading to different equations of parabola. We analyzed the impacts of factors such as confinement ratio and restrain stiffness on confined concrete compressive strength, ultimate strain and other control parameters through finite element analysis. The results show that the confinement ratio determines the confinement status, and the increase of the confinement ratio has a limited capacity to increase the compressive strength, The deformation of confined concrete is influenced by restrain stiffness. The stronger the restrain stiffness is, the less the lateral deformation is and the greater ultimate axial strain will be. The consideration of equivalent section coefficient kse is needed in the non-circular section confined concrete. We analyzed the results and proposed boundary values of strong and weak confinement styles, a peak/inflection point stress and strain model, and a compressive strength and ultimate strain model.     

An inverse method for online stress monitoring and fatigue life analysis of boiler drums

A method based on solution of the inverse heat conduction problem was presented for online stress monitoring and fatigue life analysis of boiler drums. The mathematical model of the drum temperature distribution is based on the assumptions that the difference of temperature along the longitudinal axis of the boiler drum is negligible with changes only in the radial direction and the circumferential direction, and that the outer surface of drum is thermaUy insulated. Combining this model with the control-volume method provides temperatures at different points on a cross-section of the drum. With the temperature data, the stresses and the life expectancy of the boiler drum are derived according to the ASME code. Applying this method to the cold start-up process of a 300 MW boiler demonstrated the absence of errors caused by the boundary condition assumptions on the inner surface of the drum and testified that the method is an applicable technique for the online stress monitoring and fatigue life analysis of boiler drums.     

大体积混凝土裂缝控制技术在工程中的应用

文章介绍了大体积混凝土的裂缝控制技术。从原材料、混凝土配合比设计、施工技术措施以及温度应力计算及温控方案等方面,论述了大体积混凝土裂缝控制的保证措施。     

立体几何中圆锥曲线类型的判定

立体几何中圆锥曲线类型的判定主要利用转化的数学思想方法：将三维的立体几何中轨迹问题转化成平面几何中圆锥曲线类型的判定．常用的方法有：（1）定义法;（2）轨迹方程法;（3）交轨法．若所求的点的轨迹所在的平面与空间直角坐标平面垂直或平行则可运用“轨迹法”求出该点的轨迹方程．再结合平面解析几何中的圆锥曲线方程的类型即可判断．否则只能利用平面解析几何中的圆锥曲线的定义加以判断．特殊的可用“交轨法”．     

利用组件技术增强网络课件交互功能的探索——生物信息学算法示教的实现

介绍了多媒体网络课件中的交互式技术,提出利用网络组件,通过Web浏览器运行Linux平台生物信息软件,并实现网络课件中交互功能的方案。基于这一方案,开发了生物信息学网络课件的部分内容,构建了Blast、Emboss等常见生物信息学算法和软件的运行环境,实现了网络环境下生物信息学算法教学的实践环节。