Effect of vertical load difference on cracking behaviors in multistory masonry buildings and numerical simulation

To investigate the causes qf cracks in multistory masonry buildings, the effect of vertical load difference on cracking behaviors was investigated experimentally by testing and measuring the displacements at the testing points of a large sized real masonry U-shaped model. Additionally, the cracking behaviors in U-shaped model were analyzed with shear stress and numerical simulated with ANSYS software. The experimental results show that the deformation increases with the increase of the vertical load. The vertical load results in different deformation between the bearing wall and non-bearing wall, which leads to cracking on the non-beating wall. The rapid deformation happens at 160 kN and cracks occur firstly at the top section of non-bearing wall near to the bearing wall. New cracks are observed and the previous cracks are enlarged and developed with the increase of vertical load. The maximum crack opening reaches 12 mm, and the non-bearing wall is about to collapse when the vertical load arrives at 380 kN. Theoretical analysis indicates that the shear stress reaches the maximum value at the top section of the non-bearing wall, and thus cracks tend to happen at the top section of the non-bearing wall. Numerical simulation results about the cracking behaviors are in good agreement with experiments results.

Elastic solutions for partially embedded single piles subjected to simultaneous axial and lateral loading

In order to improve the design level of partially embedded single piles under simultaneous axial and lateral loads, the differential solutions were deduced, in which the soil was treated as an ideal, elastic, homogeneous, semi-infinite isotropic medium. A comparison was made between model test results and the obtained solutions to show their validity. The calculation results indicate that the horizontal displacement and bending moment of the pile increase with increases of the axial and lateral loads. The maximum horizontal displacement and bending moment decrease by 37.9% and 13.9%, respectively, when the elastic modulus of soil increases from 4 MPa to 20 MPa. The Poisson ratio of soil plays a marginal role in pile responses. There is a critical pile length under the ground, beyond which the pile behaves as though it was infinitely long. The presented solutions can make allowance for the continuous nature of soil, and if condition permits, they can approach exact ones.

Study on the subgrade deformation under high-speed train loading and water–soil interaction

It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy regions.This study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under high-speed train loading based on vehicle–track coupling dynamics.By using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the high-speed train loading,are studied.The main factors-the permeability coefficien and the porosity-influencin the subgrade deformation are investigated.The developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of water-rich soil.

国内若干主要城市纺织品色彩爱好分布图

本文运用因子分析、聚类分析等多元统计分析方法,以48种色彩作为讨论对象,对全国32个具有一定代表性地区的色彩爱好调研资料进行分析.通过分析,32个地区作总体的色彩爱好主要由六个基本特征来描述,且根据色彩爱好的差异程度,32个地区可划归至五种类型的色彩爱好:南方城市型、北方城市型、江南地区型、东北地区型及交错型。

Analysis of flow response to fluctuation of rotational speed in a radial impeller

By discretizing the convection terms with AUSM+-up scheme in the rotating coordinate system,a finite volume analysis code based on multi-block structured grids was developed independently so as to realize the numerical solving of internal flow fields of turbomachineries.Taking an unshrouded radial impeller with the working fluid of water vapour as the research object,the flow response to the fluctuation of rotational speed was calculated.By comparing the surface pressure profiles and velocity contours calculated by the code and commercial software respectively,the accuracy of flow solver was verified.The analysis of flow response data indicates that,as the working condition shifts closer towards the surge boundary,the response of flow parameters such as mass flow and aerodynamic torque will be more nonsynchronous with the fluctuation of rotational speed,and also the influence of density variation on mass flow variation will be smaller.Moreover,the transient variation region of working condition performance will deviate farther away from the steady performance curve as the working condition approaches the surge boundary.Compared to the working conditions with small mass flows,the distribution characteristics of pressure difference load on the blade surface vary little under large mass flow conditions.The reduction of fluctuation amplitude of rotational speed exerts no influence on abating the hysteresis of flow response.

Optimal Thermal Insulation Thickness in Isolated Air-Conditioned Buildings and Economic Analysis

The removal building heat load and electrical power consumption by air conditioning system are proportional to the outside conditions and solar radiation intensity. Building construction materials has substantial effects on the transmission heat through outer walls, ceiling and glazing windows. Good thermal isolation for buildings is important to reduce the transmitted heat and consumed power. The buildings models are constructed from common materials with 0 - 16 cm of thermal insulation thickness in the outer walls and ceilings, and double-layers glazing windows. The building heat loads were calculated for two types of walls and ceiling with and without thermal insulation. The cooling load temperature difference method, CLTD, was used to estimate the building heat load during a 24-hour each day throughout spring, summer, autumn and winter seasons. The annual cooling degree-day, CDD was used to estimate the optimal thermal insulation thickness and payback period with including the solar radiation effect on the outer walls surfaces. The average saved energy percentage in summer, spring, autumn and winter are 35.5%, 32.8%, 33.2% and 30.7% respectively, and average yearly saved energy is about of 33.5%. The optimal thermal insulation thickness was obtained between 7 - 12 cm and payback period of 20 - 30 month for some Egyptian Cities according to the Latitude and annual degree-days.

Inverse Proportion Technique Based Scheduling Strategy for Energy Storage System Considering Load Demand Differences

The energy storage system(ESS)as a demand-side management(DSM)resource can effectively smooth the load power fluctuation of a power system.However,designing a more reasonable ESS operational strategy will be a prerequisite before incorporating the energy storage device into DSM.As different load levels have different demands for the real-time chargedischarge power of an ESS,this paper proposes a heuristic ESS operation scheduling strategy which can take into account the electrical load demand differences.In this paper,firstly,two demand degree concepts for charging power and discharging power are defined to describe the differentiated ESS demand under the condition of different electrical load levels.Secondly,an inverse proportion technique based ESS scheduling strategy,with the consideration of the load demand difference,is proposed in this paper.Thirdly,some evaluating indices are defined in this paper for describing the influence of the proposed strategy on the smoothing degree of the daily load curve.Finally,several case studies are designed to verify the validity and correctness of the proposed technique,and the results show that the proposed technique can effectively smooth the load curve and improve the ability of peak shaving and valley filling.

基于差分蜂群算法的电力系统经济负荷分配

针对电力系统经济负荷分配问题,提出一种有效的差分蜂群算法.受差分进化算法的启发,该算法基于差分进化操作改进了雇佣蜂的搜索方式,提高了探索能力和收敛速度.此外,提出一种有效的修复机制以保证新个体的可行性.该算法在带有阀点效应和多燃料特征的典型电力系统经济负荷分配问题上进行了测试.仿真结果验证了所提算法的有效性.