基于ANSYS的钢筋混凝土坡屋盖优化设计

以目前实际工程中应用较多的钢筋混凝土坡屋盖作为研究对象，使用ANSYS有限元软件分析结构受力特性，并按分部优化法对结构进行了优化，从而使坡屋盖结构在减轻重量、节省材料、简化施工的同时，结构的受力状况得到改善。     

有限元程序在衬砌结构设计中的应用

隧道在一般情况下应做衬砌,其结构类型及尺寸可根据围岩类型、衬砌工作特点,并考虑施工条件等,通过工程类比、结构计算或必要的试验确定。以龙池山隧道为工程背景,对衬砌计算模型进行了合理的简化处理,优化了计算结果,在衬砌结构的检算中应用杆系结构有限元分析的理论及方法,通过FORTRAN90计算程序进行了实现。经过检算,衬砌结构安全稳定性满足设计要求。     

分析模型对大跨度空间结构分析的影响

文章以东丽体育中心网球馆工程为背景,通过详细的有限元分析比较,说明了不同分析简化方法对结构大跨度钢结构屋盖工程的设计影响.此外,根据分析结果,对比说明了上述弧形网架结构在周边支撑的条件下,其受力变形的特点以及优化的方向.     

基于明挖预制结构的防水设计及适用性研究

依托实际工程案例并结合当前预制装配式结构的自身特点,对明挖法中预制结构的防水设计进行优化,在明挖预制结构中采用接缝柔性防水设计,并通过室内试验和现场应用进行适应性研究,最终实现在预制结构防水工程施工中简化工序、降低造价、缩短工期的目的。     

结合实例对比分析双层矩形综合池结构计算方法

结合工程实例,对双层矩形综合池结构设计中采用的简化计算方法的合理性进行探讨。分别采用Midas/Gen有限元软件以及简化计算方法对双层矩形综合池进行了满水荷载作用下的结构内力计算,并将计算结果进行对比分析,指出了双层综合池结构设计中采用刚架的简化计算方法是能满足工程精度要求的简便计算方法,而分层计算的分离式简化计算方法由于计算精度无法满足设计要求,从而不应采用。     

山区河流取水扩建工程的优化设计及施工

在某山区河流固定坝取水工程改扩建工程中,采用了对原坝进行扩建并对地基加固处理的优化方案,运用了固结灌浆的地基处理技术.介绍了工艺及结构的优化设计,以及在不中断供水前提下的关键施工技术.该优化设计及施工方案使得土建结构简化、经济、实用、安全可靠,对类似工程具有参考意义.     

基于均匀化方法的多孔板结构设计数值研究

多孔板结构一直存在计算复杂的问题.采用均匀化方法对多孔板结构进行有效的简化,利用有限元软件ANSYS对其进行数值模拟研究,提出了用于计算多孔板结构的经验公式,简化了工程计算和设计.参考正交试验设计法选取了多个工程实例,通过对比经验公式计算结果和数值分析结果,验证了公式的可靠性.     

考虑桩土相互作用近海风电系统模态分析

近海工程结构必须考虑桩土相互作用的影响。介绍了采用导管架结构的近海风力发电结构基础的不同简化方法。对于不同的简化方法,用ANSYS软件对不同的模型进行了模态分析,求出了前6阶自振频率,并且将不同约束条件下所得结果相互比较,探讨了适用于求解自振频率的简化方法。得到了此类结构进行模态分析时必须考虑桩土相互作用的结论。     

镇江体育会展馆张弦桁架优化设计分析

镇江体育会展馆屋盖属于大跨度张弦桁架结构.首先以整体结构为研究对象,除对单榀张弦桁架进行设计外,着重对张弦桁架的侧向支撑进行了简化和优化设计.根据本工程的特点,沿整体桁架四周增加了对称拉索.然后对优化前后结构的力学性能进行了分析.分析结果表明:优化后结构更加简单,施工安装难度大大降低,结构应力峰值减小,结构挠度减少;优化后结构的基频增加,地震响应峰值减小,竖向刚度大大增加,结构抵抗地震能力增强.因此,张弦桁架结构优化分析应根据整体结构的特点,除进行单榀张弦桁架优化外还应重视其侧向支撑的设计优化.     

板柱房屋隔震及地震作用的计算简化方法

板柱基础隔震结构是一种无梁楼盖结构和隔震系统的结合,它有许多优点,但是实际工程中应用还很少.首先论述了这种结构的优越性和存在的问题,然后探讨了一种在地震作用下适用于这种结构的简化计算方法.这种方法是在等效侧力法的基础上提出的对板柱基础隔震结构进行计算和设计的方法,该方法属于简化设计方法,能够为实际工程的计算和设计提供一定的参考.     

Application of model based predictive control for water-based floor heating in low energy residential buildings

A model based predictive control method is applied in order to determine the optimal supply fluid temperature in the case of concrete embedded water-based floor heating in low energy residential buildings. The aim of the control is to keep the indoor temperature within a defined comfort interval. The forthcoming supply fluid temperature is obtained through a numerical optimisation based on a prediction of the upcoming heat demand. The elementary response function, which is the basis for the method, is obtained from a numerical control volume model, and as an alternative, from a simplified 2-node lumped model. The accuracy of the results obtained from the simplified model is surprisingly good in comparison to the detailed numerical model. The control method is applied for a single room for which a perfect prognosis of the heat demand exists. The results show a fairly steady optimised supply fluid temperature.     

Convergence-confinement approach for designing tunnel face reinforcement by horizontal bolting

The ground reinforcement by bolting is a technique in strong development. Bringing a perennial supplement of resistance to the ground, this technique permits to use poor grounds in a sensitive environment. It can be particularly, used for the reinforcement of tunnel faces.The full numerical simulation of such works remains a heavy and expensive process, notably in terms of geometrical complexity and various scale levels. During the preliminary project stage, it appears necessary to have simplified models, making possible to simply appreciate the effectiveness of the reinforcement.The existing simplified methods being not well adapted for the optimal conception of these reinforcement systems, a new method based on the convergence confinement approach is proposed and tested in this paper.     

Ground movement prediction for tunnels using simplified procedure

Stochastic medium theory is an effective method to predict tunneling-induced ground surface movement. However, the calculation formula of this theory is a complex double integral and the limit of integration is difficult to obtain when the cross section of tunnel is non-circular. In this paper, the stochastic medium theory is simplified, and the simplified procedure is proposed to predict the ground surface movement. In order to evaluate the validity of the simplified procedure, the numerical results using the stochastic medium theory are compared with those using the simplified procedure. The comparisons show that the present results by the simplified method agree well with the results by the stochastic medium theory except for very shallow tunnel, which means that the simplified method is an effective technique for predicting ground surface movement.     

受压U肋加劲板局部稳定受力性能数值模拟

为了掌握受压U肋加劲板的局部稳定受力性能,考虑残余应力与初始几何缺陷,建立U肋加劲板局部稳定试验试件的有限元模型,通过考虑不同宽厚比的试验验证该数值模拟方法的正确性;将U肋加劲板及其腹板简化为四边简支板,并通过数值模拟方法验证四边简支板简化模型的正确性。结果表明:采用数值模拟方法计算得到的破坏模态和应力 位移曲线与试验曲线吻合较好,所计入的残余应力和几何缺陷大小是合理的;采用简化的四边简支板模型和试验试件模型计算的应力 位移曲线从开始到峰值吻合较好,在下降段四边简支板模型下降斜率有所增大;在分析受压U肋加劲板受力性能时,可以选用等效四边简支板简化模型分析其局部稳定承载力。     

Integrated multi‐type sensor placement and response reconstruction method for high‐rise buildings under unknown seismic loading

Structural health monitoring system has been implemented on high‐rise buildings to provide real‐time measurement of structural responses for evaluating their serviceability, safety, and sustainability. However, because of the complex structural configuration of a high‐rise building and the limited number of sensors installed in the building, the complete evaluation of structural performance of the building in terms of the information directly recorded by a structural health monitoring system is almost impossible. This is particularly true when seismic‐induced ground motion is unknown. This paper thus proposes an integrated method that enables the optimal placement of multi‐type sensors on a high‐rise building on one hand and the reconstruction of structural responses and excitations using the information from the optimally located sensors on the other hand. The structural responses measured from multi‐type sensors are fused to estimate the full state of the building in the modal coordinates using Kalman filters, from which the structural responses at unmeasured locations and the seismic‐induced ground motion can be reconstructed. The optimal multi‐type sensor placement is simultaneously achieved by minimizing the overall estimation errors of structural responses at the locations of interest to a desired target level. A numerical study using a simplified finite element model of a high‐rise building is performed to illustrate the effectiveness and accuracy of the proposed method. The numerical results show that by using 3 types of sensors (inclinometers, Global Positioning System, and accelerometers), the proposed method offers an effective way to design a multi‐type sensor system, and the multi‐type sensors at their optimal locations can produce sufficient information on the response and excitation reconstruction.     

钢筋混凝土柱低周疲劳全过程累积损伤性能简化分析方法

为了有效预测地震作用下钢筋混凝土柱的低周疲劳损伤累积程度与损伤后的剩余承载能力,提出了一种 基于单调荷载-位移关系并考虑低周疲劳效应的钢筋混凝土柱损伤承载能力简化分析方法。首先,根据自洽方法 并假设裂纹符合Weibull分布,提出了基于细观机理的混凝土损伤模型,给出了混凝土损伤指标与有效模量、应 变的定量表达式,并通过非线性数值分析得到了钢筋混凝土柱的单调荷载-变形曲线;然后,通过分析纵筋的塑 性低周疲劳损伤,建立了基于割线刚度的钢筋混凝土柱低周疲劳变形性能损伤计算模型,模型参数根据试验研究 获得,推导了柱割线刚度和抗力的衰减规律计算公式;最后,在以上工作的基础上,分析低周疲劳作用对钢筋混 凝土柱底截面混凝土和纵筋应变的累积增大效应,得到混凝土损伤后的有效弹性模量,提出了考虑低周疲劳损伤 后的钢筋混凝土柱承载能力和变形能力计算方法。编制非线性损伤分析程序,对损伤后试验柱进行了计算分析。 结果表明,该方法得到的计算值与试验值的相对误差处于合理范围之内,验证了该方法的可靠性和实用性。     

隔震结构地震响应的简化计算方法

通过将实振型分解法与随机振动理论相结合,借鉴SRSS思想给出了利用位移反应谱来估计隔震层位移及上部结构层间剪力的方法,并对算例的结果进行对比,指出建立的位移反应谱估计方法是一种能满足工程计算精度的简化计算方法。     

舰船振动声辐射特性模型试验简化方法研究

舰船水下振动声辐射试验模型简化方法研究对于舰船噪声测量具有重要的参考价值.依据实船结构,提出了多种舰船振动声辐射模型试验简化方案;联合应用声固耦合法及统计能量法,通过数值试验对比分析了各简化方案的水下振动及声辐射特性,探索了模型缩尺比对舰船简化方案声学特性的影响规律.结果表明:从验证指导舰船结构声学设计的角度出发,方案二均能精确地反映舰船的振动及声辐射特性,误差小于2.5dB;为了兼顾经济因素,建议选取方案六缩比模型,可简化模型质量约1/2.初步给出了兼顾评估精度和试验经济性的舰船振动声辐射模型简化方法.     

Robust active control against wind-induced structural vibrations

Slender flexible structures are vulnerable to vibrations under wind loads. The dynamic model of a frame-like structure is obtained by finite element approximation in this paper and used further for the design of an active control mechanism. The behavior of the structure is described by simplified linear equations. A linear quadratic regulator and an H₂ optimal control method are used for the suppression of the extended vibration effects. Structured uncertainties are considered to reflect the errors between the model and the reality. To accommodate directly the plant uncertainties and to obtain a best possible performance in the face of uncertainties a robust H_∞ optimal control for active control structure is used. The two latter robust controllers take into account as well incompleteness of the measured information, a fact that cannot be neglected in civil engineering, and lead to applicable designs of smart structures. The numerical simulation shows that vibrations can be suppressed by means of the proposed methods.     

带约束拉杆方形钢管混凝土柱偏压性能

介绍了14个带约束拉杆方形钢管混凝土单向偏压柱试件的试验研究结果,研究试件在不同的含钢率、约束拉杆设置参数以及偏心率下的力学性能。研究结果表明约束拉杆有助提高方形钢管混凝土偏压短柱的承载力和延性。同时,利用国内现有规程GJB 4142—2000、DBJ 13—51—2003以及CECS 159:2004对试件承载力进行计算,规程计算结果总体上低估了带约束拉杆方形钢管混凝土偏压试件承载力试验结果。采用带约束拉杆方形钢管混凝土的本构关系,利用条带法对试件承载力进行数值计算,计算结果与试验结果吻合良好。利用该数值方法对带约束拉杆方形钢管混凝土偏压柱进行参数研究,分析约束拉杆约束系数、钢材屈服强度、混凝土强度、截面含钢率以及长细比等主要参数对N/Nu-M/Mu曲线的影响,在此基础上提出适合带约束拉杆方形钢管混凝土偏压柱承载力简化计算公式。该简化公式计算结果与数值计算结果基本吻合,且总体上偏于安全。