300 MW汽轮发电机组转子轴系的模化及固有特性分析

根据汽轮发电机组转子轴系的结构特点建立了一种大型转子轴系弹性连续体扭振模型 ,推导了轴系连续质量分布系统的扭振波动方程 ,进行了 3 0 0 MW汽轮发电机组轴系扭振固有特性的解析研究和计算分析     

守恒原理在多球弹性碰撞中的应用

本文应用守恒原理分析球与地球及球与球之间的弹性碰撞 ,得到了某些令人感兴趣的结果     

三折线线性软化土体中球孔扩张问题解答

以三折线线性软化模型为基础,结合Tresca屈服准则和不相关联的流动法则,同时考虑了塑性区弹性变形,推导了具有应变软化和剪胀特性的土体球孔扩张问题的解。运用所得解分析了不同剪胀特性和不同软化程度对球形孔扩张结果的影响。     

Numerical Derivation of Strain Rate Effects on Material Properties of Masonry with Solid Clay Bricks

In this paper, numerical method is used to study the strain rate effect on masonry materials. A typical unit of masonry is selected to serve as a representative volume element (RVE). Numerical model of RVE is established with detailed distinctive modeling of brick and mortar with their respective dynamic material properties obtained from laboratory tests. The behavior of brick and mortar are characterized by a dynamic damage model that accounts for rate-sensitive and pressuredependent properties of masonry materials. Dynamic loads of different loading rates are applied to RVE. The equivalent homogenized uniaxial compressive strength, threshold strain and elastic modulus in three directions of the masonry are derived from the simulated responses of the RVE. The strain rate effect on the masonry material with clay brick and mortar, such as the dynamic increase factor (DIF) of the ultimate strength and elastic modulus as a function of strain rate are derived from the numerical results.     

波浪滑翔机弹性水翼性能模型试验

波浪滑翔机的推力是由一组可以随着机体自动翻转的水翼来获得的。通过波浪水池模型试验对波浪滑翔机弹性水翼性能进行了研究,制作了波浪滑翔机水下牵引机的1:2.5缩尺模型,利用自制的垂荡激励拖车连接水下牵引机模拟在不同波高条件,分析不同情况下弹性水翼的性能。试验表明,波浪滑翔机水翼弹簧刚度应该根据工作海域的海况选取,海况较恶劣的海域波浪滑翔机弹性水翼可以选择较大的弹簧刚度;反之,水翼刚度不宜过大。     

Element-free Galerkin method for free vibration of rectangular plates with interior elastic point supports and elastically restrained edges

The element-free Galerkin method is proposed to solve free vibration of rectangular plates with finite interior elastic point supports and elastically restrained edges.Based on the extended Hamilton＇s principle for the elastic dynamics system,the dimensionless equations of motion of rectangular plates with finite interior elastic point supports and the edge elastically restrained are established using the element-free Galerkin method.Through numerical calculation,curves of the natural frequency of thin plates with three edges simply supported and one edge elastically restrained,and three edges clamped and the other edge elastically restrained versus the spring constant,locations of elastic point support and the elastic stiffness of edge elastically restrained are obtained.Effects of elastic point supports and edge elastically restrained on the free vibration characteristics of the thin plates are analyzed.     

超细长弹杆非线形力学的建模与分析

Nonlinear mechanics for a super-thin elastic rodwith the biological background of DNA super-coilingmacromolecules is aninterdisciplinary research area ofclassical mechanics and molecular biology.It is also asubject of dynamics and elasticity because elastic bod-ies are analyzedviathe theory of dynamics .It is infrontiers of general mechanics (dynamics and con-trol) . This dissertation is devoted to model a con-strained super-thin elastic rod and analyze its stabilityin equilibrium. The exist…     

河南农村居民消费结构分析

消费结构是衡量居民生活水平、生活质量的一条重要途径。河南农民对子女教育及其自身素质的提高比较重视,富裕后的追求上升;文化教育、家电、通信、交通、住房、旅游等方面的消费将成为增长点;政府应制定相关政策,鼓励这些消费。     

弹簧质量对振子运动的影响

通过求解弹簧中纵波的波动方程，讨论了弹簧质量对振子的振动频率及弹簧劲度系数的影响。     

再生骨料取代率对混凝土抗压性能的影响

以再生骨料、天然骨料、河砂、P·O42．5R．普通硅酸盐水泥、粉煤灰、S95粒化高炉矿渣粉、自研的MPE—GAA—AA—AMPS三元共聚聚羧酸类高效减水剂为主要原料,通过再生骨料不同取代率制作了520个再生骨料混凝土试块,运用普通混凝土力学性能试验方法,对再生骨料混凝土的抗压强度、回弹值、弹性模量和单轴受压进行综合试验。结果显示：再生骨料混凝土抗压强度的发展规律与普通混凝土存在一些差异：再生骨料取代率直接影响着再生骨料混凝土各龄期的抗压强度、单轴受压应力一应变关系、弹性模量以及再生骨料混凝土修正后回弹值。通过加入自研的MPEG从-从-AMPS三元共聚聚羧酸类高效减水剂,以50％再生骨料取代率,配制设计强度为30MPa的再生骨料混凝土是最切合实际的。