A Study on Flow Field with Swirling in Combustion Chamber

The method of structural damage assessment based on changes in eigenvalues has some defects.Therefore,this paper presents a method of damage assessment of frame structures based on changes in mode.The adaptability and efficiency of this method are discussed through computation simulation.The results indicate that this method is feasible.     

A Preliminary Survey on Analysis Method of Building Structures Under Post-Earthquake Fire

Considering the impact of post-earthquake fire on building structures in structure design, an analysis method is proposed to analyze and simulate the response of building structures under post-earthquake fire. Based on the seismic response and thermal stress analysis, this method considers the structure seismic damage through a simplified seismic damage model, and the simulation of the response of building structures under post-earthquake fire was reached by linking the heat transfer analysis and thermal stress analysis to the results of seismic damage. A single-storey concrete frame and a multi-story concrete frame were analyzed with this method and compared with experimental results of the same concrete frame under fire without seismic damage. It is shown that the collapse mode may change for seismic damaged structures and the fire resistance decreases with the increasing of seismic damage degree.     

Multi-dimensional Life Cycle Economic Cost Assessment for Super Tall Building Structures

Super-tall building structures have the features of complex structural systems, diverse structural functions, long service life, massive investment and fixed owners. The life-cycle cost of super-tall building structures mainly contains initial cost, maintenance cost, failure cost caused by hazard and demolition cost. In order to achieve the minimization of the life-cycle cost of the super-tall building structure, a multi-dimensional life cycle economic cost assessment method is proposed in this study. The proposed method considers alternative design schemes, structural components and cost items. The overall cost management and optimization will be done at the initial phase of the structural project if this method can be employed. The proposed method is applied to a super tall building to illustrate its effectiveness and applicability.     

A New Earthquake Damage Model for RC Structure

During the process of seismic design of structures, prediction of earthquake damage in future and estimation of economic loss after earthquake, it is important task to select appropriate variables to establish damage models for offering quantitatively the damage indices of structures under earthquake. In this article a few types of damage variables and some two-parameter damage models are first analyzed, then a new damage model on the basis of damage mechanics is proposed and at last the value of the parameter in the model is given.     

海洋溢油损失评估体系构建

全球海洋溢油事故频繁发生,已经成为影响经济发展、生态平衡、社会稳定发展的重要制约因素。因此,建立一套全面、系统的海洋溢油损失评估体系非常重要。在前人的研究基础上,将海洋溢油损失分为直接损失及间接损失,建立其子评估指标并提供货币化评估模型及方法,运用直接市场法、问卷调查法、替代成本法、成果参照法、碳税法、影子工程法、恢复费用法等一系列评估方法进行构建。构建全面、系统的海洋溢油损失评估体系能对海洋溢油损失进行有效的货币化定量分析,为中国海洋溢油事故后续赔偿、提高溢油事故应急能力等提供依据。     

The Research of Landslide Hazards Assessment System

Landslides caused substantial damage to property,which is seriously hampering social development.With the use of geographic information systems(Arcview),a risk assessment system is established in the paper.The failure probability of 3D-slope is calculated using the Monte Carlo method.The risk of life and economic losses were also calculated by the risk assessment system.By a case study,the results of the risk of life and economic losses may be crucial foundations for administrant branch.     

Numerical Simulation Analysis on Ductility Performance of High Strength RC Frame Structure

High-strength concrete has been widely used in civil structures for advantages of higher-strength, earlier curing strength and smaller deformation in applications. However, relatively weak ductility in structures in seismic zones prevented it from further application. The ductility of the structure can be improved by reinforcing reasonably rebars in correct details. A high strength RC frame model with twelve floors and two bays is numerically analyzed by using DRAIN-2DX program. It was shown that this worked fairly well in simulation of the process of structural damage and energy dissipation capacity. It also showed that this kind of frame structure has good ductility and dissipation capacity as well as great seismic performance. The proposed method can be applied in high-strength concrete structures in seismic zone.     

Wind Damage Estimation and Prediction of Light Steel Industrial Buildings

Wind hazard damage estimation was addressed for light steel industrial buildings which were the typical wind vulnerable structures in southeast coastal cities. With parametric analysis of wind damage and the structural failure features, the envelop elements and the connecting elements were determined as the pivots of the damage analysis. Upon the consideration of the co effect of exterior wind pressure, wind induced internal pressure and windborne debris damage, a typhoon load model was proposed. And with the calculation method of the element resistance from the regulation, the procedure of the damage estimation was described and the damage classification of industrial buildings was specified with detailed indicators. Finally, the proposed method was approved with the actual data of typhoon CHANCHU (0601).     

Fuzzy Assessment Method for Seismic Damage of CFST Arch Bridges

In order to investigate the conditions of damage and failure of concrete-filled steel tube(CFST) arch bridges, considering the structural and mechanical characteristics of CFST arch bridges, the dual damage criteria assessment models of the various components based on deformation or strength and energy were developed. The nonlinear seismic response of CFST arch bridges was analyzed by finite element method and the fuzzy evaluation method of seismic damage based on fuzzy theory and analytic hierarchy process was studied. Finally, taking a long-span CFST arch bridge as example, the damage index of the bridge was 0.150, 0.152, 0.172 and 0.318 respectively when the seismic peak acceleration was respectively 0.1g, 0.2g, 0.4g and 0.8g. The results show that the CFST arch bridge is slightly damaged under the earthquake when the seismic peak acceleration is 0.4g, and the bridge is damaged moderately when the peak acceleration is 0.8g.     

基于GIS的洪灾损失评估方法

洪灾损失评估是防洪减灾领域的一项基础性工作。笔者在国内外洪灾损失评估信息系统研究的基础上，对现有的洪灾损失评估方法进行了探讨，论述了GIS技术在洪灾损失评估中的应用、特点及作用等，并提出了洪灾损失评估有待解决的问题及未来发展趋势，为科学、有效的采取防洪减灾措施提供一定的参考依据。     

Low-cyclic Fatigue Behavior of Reinforced Concrete Column Subjected to Symmetric Displacement Cycling

Under seismic action, the damage of critical regions in ductile reinforced concrete structures can be regarded as combined results of cumulative damage caused by positive/ negative displacements with different displacement levels after yielding. On the basis of symmetric low-cyclic fatigue experiments on eight half-scale RC columns under different displacement levels, the development of cumulative damage and relationships between low-cyclic fatigue life and symmetric displacement amplitude are investigated. It is hoped that on this ground, more rational damage criteria for RC structures can be put forward.     

Monitoring and Assessment of Tie on the Caiyuanba Yangtze Bridge

The monitoring and assessment scheme of the Caiyuanba Yangtze Bridge is present by sensitivity analysis. The mechanics character of the six ties is studied by numerical simulation, and then the sensor location and selection are discussed considering the technique of sensor and construction situation. The trend of the displacement at the sensor location is analyzed according to different damage level of ties, the pattern associating with several displacements which are sensitive to damage at ties is bring forward to improve assessment reliability. The result can assist implement of structural health monitoring system to the same type as this bridge.     

卫星遥感在森林病虫害监测上的研究进展

总结了近20年来卫星遥感技术在森林病虫害监测领域的研究进展,并概括了遥感监测模型的主要应用形式,指出了目前卫星遥感监测森林病虫害工作的局限性,展望了其应用前景。目的在于为卫星遥感监测森林病虫害工作提供一种有益的启示。     

Distribution of Earthquake Total Input Energy of Structures

This paper discusses the distribution regularity of earthquake total input energy of structures between hysteretic energy and damping energy and their influencing factors taking account of various factors.The results can serve as the basis for the energy method of aseismic structural design and energy analysis in the study of damage criteria.     

Quantitative analysis of damage extent of transmission tower by using strain energy method

In order to solve the structural damage identification problem of transmission tower, a two-step identification method based on change rate and dissipation rate of modal strain energy is proposed. The damage location is identified by the change rate of modal strain energy method. Then, the modal strain energy dissipation rate theory is analyzed further by using the element stiffness matrix after injury. As a result, a more accurate damage quantification equation method is introduced. This method requires only several modals of vibration. The numerical simulation results show that this two-step method can find the damage location and damage degree of transmission towers effectively.     

基于主成分分析的湖北省洪涝灾害风险评估模型构建

湖北省历年由洪涝灾害造成农作物受损严重,对湖北省进行洪涝风险评估十分必要。本文提出了一种定量化风险评估的模型建立方法,通过多源数据（气象、社会经济、地理特征等数据）提取到15个指标,采取主成分分析法确定各因子对于洪涝灾害的影响权重,建立风险评估模型,并运用地理信息系统(GIS)分析技术得出洪涝灾害风险区划图。在现有评估指标体系的基础上,通过网络爬虫方式获取更能反映防减灾能力的灾害应急指标;采用主成分分析方法降低模型建立中的主观因素。结果表明：（1）通过模型得到降雨与地势为湖北省洪灾发生的最主要因素;（2）湖北省中东部地区多为高风险区,其中东部武汉、黄石等长江干流途经地区处于重风险区;西南部多为中风险区,西北部在全省为低风险区。综上,该模型可为湖北省开展综合减灾、调整区域可持续发展结构、进行准确农情监测提供科学支撑和决策依据,具有重要的科学和实践意义。     

AHP-based System for the Health Assessment of Ancient and Famous Trees in Dongguan

By establishing an AHP-based assessment index system and assessment model,and applying detection technology that is convenient and harmless for ancient and famous trees,this paper is significant for investigating and assessing the health state of ancient and famous trees,and protecting the limited resources. Fourteen indexes such as growth vigor,disease and pest were selected from the perspectives of overall situation,canopy,trunk and root,and AHP(applied analytic hierarchy process) was applied to define weights of these indexes. According to the results,top 3 indexes in terms of weight are tree vigor,treetop death,internal decay and hole,while the indexes with lower weight are parasitism,root damage,ventilation and permeability. On the basis of assessment model and method as well as field investigation,health grade of ancient and famous trees(A) can be obtained. By grading the health of ancient and famous trees into 3 levels,each level indicates a certain health state,so managers can take corresponding maintenance measures to develop the best ecological and social value of these trees.     

极端气候事件对1978—2017年广西农作物的灾损影响

为了降低极端气候事件对农作物产量与经济的损失,本文基于灾害学理论,运用数理统计的趋势分析等方法,分析了1978—2017年旱灾、水灾、风雹灾与低温成灾4种极端气候事件对广西区农作物成灾、受灾面积的影响。并用极端气候事件的气候因素响应频率来近似代替一定区域极端气候发生的概率,结合1978—2017年4种极端气候事件灾损评估,对广西区旱灾、水灾、风雹灾与低温成灾进行时空分析,揭示其时空变化趋势。结果表明:（1）研究期内,广西区农作物因灾致损程度为:旱灾>水灾>低温成灾>风雹灾;（2）广西区由旱灾引起的农作物受灾面积与成灾面积呈下降趋势,因灾致损严重区域由中部与西部逐步变化至西南部与东北部;（3）广西区由水灾引起的农作物受灾面积与成灾面积变化呈上升趋势,因灾致损严重区域由南部向中西部逐渐变化;（4）广西区由风雹灾引起的农作物受灾面积与成灾面积变化呈下降趋势,因灾致损严重区域由北部与南部向中部与南部逐渐变化;（5）广西区由低温成灾引起的农作物受灾面积与成灾面积变化呈上升趋势,因灾致损严重区域主要集中在北部。     

引种马来西亚10号番木瓜气候适应性评估

摘要：霜冻害是番木瓜生产的主要气象灾害,探讨番木瓜的冻害指标对番木瓜的合理布局和低温预警具有重要意义。为此,本文根据收集的番木瓜冻害调查资料,用极端最低气温作为番木瓜发生的温度指标进行相关分析,以期得到番木瓜的冻害指标和番木瓜的气候适应性评估结果,提出各冻害级别的种植区域划分。     

Step-by-step Method of Structural Damage Diagnosis

Base on the existing step-by-step structural damage diagnosis method, a three-step structural damage diagnosis method is developed. According to the analysis of the characteristic of genetic algorithm, a new idea of excluding the undamaged element by means of step-by-step evaluation is developed to deal with the damage diagnosis problem. In this method, sensitivity genetic algorithm is used to exclude the undamaged element step by step and residual force method is used to fix the damage district. According to the simulation research of a 2D framed structure, it is shown that the step-by-step structural damage diagnosis method can gain the ideal results when it's difficult for a single damage diagnosis method to get the good results. It is also indicated that sensitivity genetic algorithm is a good way to exclude the undamaged element step by step.