共查询到19条相似文献，搜索用时 265 毫秒
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赵刚 《杨凌职业技术学院学报》2014,(4):44-46
杆系几何组成分析是设计杆系结构的一项重要内容,也是结构力学中的一个难点。笔者针对难点抓其主要矛盾,总结出刚片和链杆的一般认定方法;应用刚片之间的联系网络图,紧凑、全面、直观地反映刚片之间的约束情况;根据刚片联系网络图直接划分构造层,逐层进行几何组成分析。使分析过程可遵循一定的程式进行,并用括号分层的形式简洁表达分析过程。 相似文献
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应用位移法求解结构内力时,对结构中含有抗弯刚度相对很大杆、有定向支承杆和内力静定杆进行分析简化处理,抽象出可反映结构主要力学特性的计算模型,可减少未知量个数,便于计算。 相似文献
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探讨分析了结构基础隔震应用中应注意的问题,提出了非线性动力时程分析计算模型并编制了程序。借助该程序,分析了基础隔震结构在地震作用下的层间位移、加速度和剪力等地震反应,并与相同结构未隔震的建筑的地震反应进行了对比。 相似文献
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探讨分析了结构基础隔震应用中应注意的问题,提出了非线性动力时程分析计算模型并编制了程序。借助该程序,分析了基础隔震结构在地震作用下的层间位移、加速度和剪力等地震反应,并与相同结构未隔震的建筑的地震反应进行了对比。 相似文献
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《邢台职业技术学院学报》2017,(3):63-67
通过对某混凝土框架结构进行消能隔震设计,利用有限元软件ETABS建立了三维计算模型,研究并分析了该结构在中遇地震作用下的层间位移角、层间剪力和附加阻尼比。分析结果表明:混凝土框架结构在中遇地震作用下,采用消能隔震设计后,其主体结构最大层间位移角能满足消能减震结构的设防目标;中震下防屈曲耗能支撑开始屈服,已经开始发挥一定的耗能作用。 相似文献
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《邢台职业技术学院学报》2015,(5):68-71
通过对某砖混结构进行建筑隔震设计,建立该结构的有限元计算模型,研究并分析其在基本地震加速度作用下的结构反应和罕遇地震作用下的隔震层层间位移反应。计算结果表明:砖混隔震结构在设计基本地震加速度作用下,隔震结构层剪力与非隔震结构层剪力相比满足计算要求;罕遇地震作用下,隔震层最大位移满足支座最大容许位移的要求。 相似文献
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石文广 《石家庄铁路职业技术学院学报》2019,(3)
基于某地铁车站近接高层房屋工程,利用三维数值计算方法计算研究了地铁车站近接房屋的地震响应。计算得到在水平地震作用下,整个结构的水平位移规律保持一致,即结构各点的变形方向一致;高层建筑最大水平位移值为134mm,最大层间位移差约9mm,层高为3900mm;车站主体结构层间位移差约0.0761mm,层高约6250mm;经验算,结构满足规范对弹性层间位移与弹性层间位移角的要求;基于时程计算给出了四条结构构造的抗震对策。 相似文献
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福建省防震减灾中心大楼采用基础隔震技术设计,文章对其进行地震反应分析.采用弹塑性时程分析的方法,比较了隔震模型和非隔震模型的地震反应.结果表明,隔震结构能较大地延长结构的自振周期,从而避开场地的特征周期;同时,隔震结构的层间位移、层间剪力和加速度反应都明显低于非隔震结构,较好地达到预期的隔震效果. 相似文献
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针对结构物在地震作用下的灾害评估问题,提出了一种基于刚度退化概念的框架结构整体与层间损伤指标.该指标通过结构静力弹塑性分析方法进行计算,利用塑性铰考虑结构的地震损伤.同时,根据能力谱方法建立了该损伤指标与抗震设防等级的关系.然后,将建议指标应用于2个3层钢筋混凝土框架结构,并与其他损伤指标进行了对比.结果表明:建议的损伤指标偏于安全,且对静力弹塑性分析的水平荷载模式不敏感;层间损伤指标能够清晰地反映各楼层的损伤情况,从而判断薄弱层的位置.最后,通过统计分析给出了结构不同性能水准与损伤指标的对应关系,为基于性能的框架结构抗震评估提供参考. 相似文献
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This study introduces measures to identify resonant （concentration of energy in a single or a few frequencies） or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function （PSDF） of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records. 相似文献
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This paper presents a method to reconstruct symmetric geometric models from point cloud with inherent symmetric structure. Symmetry types commonly found in engineering parts, i.e., translational, reflectional and rotational symmetries are considered. The reconstruction problem is formulated as a constrained optimization, where the objective function is the sum of squared distances of points to the model, and constraints are enforced to keep geometric relationships in the model. First, the explicit representations of symmetric models are presented. Then, by using the concept ofparameterized points （where the coordinate components are represented as functions rather than constants）, the distances of points to symmetric models are deduced. With these distance functions, symmetry information, for both 2D and 3D models, is uniformly represented in the process of reconstruction. The constrained optimization problem is solved by a standard nonlinear optimization method. Owing to the explicit representation of symmetry information, the computational complexity of our method is reduced greatly. Finally, examples are given to demonstrate the application of the proposed method. 相似文献
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Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan
and Wenchuan earthquake in Sichuan, China. These collapses were partially caused by the pulling forces from the transmission
lines generated from out-of-phase responses of the adjacent towers owing to spatially varying earthquake ground motions. In
this paper, a 3D finite element model of the transmission tower-line system is established considering the geometric nonlinearity
of transmission lines. The nonlinear responses of the structural system at a canyon site are analyzed subjected to spatially
varying ground motions. The spatial variations of ground motion associated with the wave passage, coherency loss, and local
site effects are given. The spatially varying ground motions are simulated stochastically based on an empirical coherency
loss function and a filtered Tajimi-Kanai power spectral density function. The site effect is considered by a transfer function
derived from 1D wave propagation theory. Compared with structural responses calculated using the uniform ground motion and
delayed excitations, numerical results indicate that seismic responses of transmission towers and power lines are amplified
when considering spatially varying ground motions including site effects. Each factor of ground motion spatial variations
has a significant effect on the seismic response of the structure, especially for the local site effect. Therefore, neglecting
the earthquake ground motion spatial variations may lead to a substantial underestimation of the response of transmission
tower-line system during strong earthquakes. Each effect of ground motion spatial variations should be incorporated in seismic
analysis of the structural system. 相似文献
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为了在设计和安装中将离心泵的地震最不利方向避开地震频发的方向,本文将离心泵简化成有限元力学模型,采用有限元法对离心泵进行模态分析,计算出固有频率和振型。采用反应谱法进行分析,地震谱从不同方向进行输入,得到各个节点随地震谱输入方向的改变而变化的位移和载荷。通过分析数据结果,建议将该模型的45～75度方向设在频繁发生地震的方向上,以避免发生最大振动。 相似文献
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The damping ratios of RC buildings and steel tower are 0. 05 and 0. 01 respectively, so a steel tower topping an RC building comprises a non-proportional damping system[1,2]. Due to the difficulty of dynamic analysis for non-proportional damping systems[3-5] , these systems are usually simplified as proportional damping ones with equivalent damping ratio. The equivalent damping ratio takes a value more than 0.01 and less than 0. 05. To compare the results calculated using the non- proportion… 相似文献
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利用有限元分析软件ALGOR对平面框架进行竖向荷载作用下静力计算、动力模态及地震响应分析计算,并同手工计算方法进行了比较 如果计算的结构类型更为复杂,则有限元分析的优点更为突出 相似文献
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Drawing valid inferences from modern measurement models is contingent upon a good fit of the data to the model. Violations of model‐data fit have numerous consequences, limiting the usefulness and applicability of the model. As Bayesian estimation is becoming more common, understanding the Bayesian approaches for evaluating model‐data fit models is critical. In this instructional module, Allison Ames and Aaron Myers provide an overview of Posterior Predictive Model Checking (PPMC), the most common Bayesian model‐data fit approach. Specifically, they review the conceptual foundation of Bayesian inference as well as PPMC and walk through the computational steps of PPMC using real‐life data examples from simple linear regression and item response theory analysis. They provide guidance for how to interpret PPMC results and discuss how to implement PPMC for other model(s) and data. The digital module contains sample data, SAS code, diagnostic quiz questions, data‐based activities, curated resources, and a glossary. 相似文献