X75海底管线管应变极限的数值模拟

采用ANSYS软件对X75海底管线管在不同的变形速率、内部压强、力学性能(屈强比、刚度等)等条件下的拉伸变形进行计算模拟,分析应变速率、内压、屈强比及刚度对X75海底管线管拉伸变形应力应变极限的影响规律。结果表明,当内压一定时,随着应变速率的增大,极限应力整体上呈逐渐增大趋势,极限应变整体上呈减小趋势;当应变速率一定时,随着内部压强的增大,极限应力和极限应变整体上呈逐渐增大趋势;随着屈强比的增大,抗拉极限应力应变呈先减小后增大的趋势;随着刚度的变化,极限应力和极限应变呈现不同的变化趋势。变化规律与实际相符,计算结果真实可信,可以为实际工业生产提供参考。

碳化混凝土受压本构关系试验研究

通过对混凝土试件碳化试验结果的分析,拟合出碳化后混凝土的受压应力-应变曲线,分析其曲线参数取值及有关特征值的变化关系,供有关工程结构可靠性评估及试验研究参考。

高强混凝土偏心受压短柱承载力的计算

在不同强度等级的高强混凝土和配筋率的偏心受压短柱试验基础上，通 过对高强混凝土极限压应变的取值、受压区混凝土应力－应变曲线形式的选 取及等效应力图形简化处理，建立起一套计算方法，并推导了相应的计算公 式．本计算方法，对工程设计和计算具有一定理论和应用价值．

室温下形状记忆合金丝拉伸力学性能试验研究

基于形状记忆合金(Shape Memory Alloy,简称SMA)的优良特性,以及其在结构振动控制、减震隔震中的应用,针对2 mm SMA丝进行了力学性能试验。通过改变2 mm SMA丝的循环次数、加载速率、加载幅值等参数,探究2 mm SMA丝各相变应力、等效阻尼比、单圈循环耗能、残余应变、极限应力应变等力学性能的变化情况。试验表明:循环次数和加载幅值是影响2 mm SMA丝力学性能的主要参数,随着循环次数的增加,2 mm SMA丝的各项力学性能不断降低,最后趋于稳定状态;随着幅值的增加,单圈循环耗能增幅最大,耗能能力不断增强;2 mm SMA丝的极限应力-应变曲线与经典应力-应变曲线的加载段基本吻合。

Discrete element approach for mine dump stability analysis

Mine overburden dumps have posed significant safety issues in the operations of various unit operations of open pit min-ing especially the external dumps. The external dumps are composed of a mixture of fragmented rocks and loose soil. Their charac-teristic is comparable to heavily discontinuous solid mass. The conventional approach of limit equilibrium methods provide safety factors for the slope but nothing about the stress-strain characteristics of the large dump mass. The designs of dump location and their respective geometry are integrated for the know-how of the stability characteristics of these dumps. The discrete element method uses a circular disk to represent the granular solid mass and their interactions are described by the Newton’s third law of motion. The displacement is described by the sliding of the circular disk. This work is focused on the modeling efficiency of the discrete element methods to represent the behaviour of mine dump masses with the specified joint plane for the limit equilibrium method. The advantage of the work lies on the ease of information retrieval at any point at the dump mass concerning the stress and strain histories, displacement, failures etc. which when integrated produces a better understanding of the stability of the dump masses.

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.

某涡轮转子破裂转速计算与试验研究

转子破裂转速的多种预测方法各有其相应的应用条件和范围,本文针对轮盘挡板组合转子的破裂转速进行了理论预测和全尺寸组合转子试验验证,结果表明基于有限元计算结果的平均应力法和极限应力应变法有良好的预测效果,挡板先于轮盘起裂且迅速扩展带来巨大转动不平衡量促使涡轮盘迅速起裂。