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概述有侧支撑直立设备(如框架内塔)的计算比较复杂,尤其是对其自振特性(如自振周期)的分析,目前,一般将其简化为按悬臂梁模型作计算,误差不小。对较大直径且较高的有侧支撑直立设备的抗震分析更觉困难,故往往只能对这类设备作保守设计,这不仅影响设备本身的设计,由于支座反力和设备任意截面处计算荷载的不准确,亦影响框架及设备附件(如设备法兰)的设计。应用电子计算机,可将有侧支撑直立设备很逼近地简化为有集中重量的非等直弹性支座连续梁,进行振动反应计算和内力分析,直至完 相似文献
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用传递矩阵法求直立塔设备的自振周期及主振型 总被引:1,自引:0,他引:1
前言直立塔设备的自振周期及主振型是直立塔设备动力学分析的重要参数,近年来,国内不少学者对这些参数的精确计算进行了有益的探讨。本文采用的传递矩阵法是在Myklested-Prohl方法的基础上加以发展的。该方法首先由N.O.Myklested和M.A.Prohl分别在研究飞机机翼振动和转轴临界转速的工作中提出,此后,Folk Fuhrke Pesdel等人对该方法加以发展,亦称之为传递矩阵法。本文推导了利用传递矩阵法计算直立塔设备自振周期和主振型的计算公式,并通过实例进行了计算和讨论。文中计算工作由APPLEI微机完成,程序采用BASIC语言编写。 相似文献
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计算塔设备自振频率的有限单元法 总被引:1,自引:0,他引:1
利用梁弯曲振动的有限单元法,编制了FORTRAN有限元计算程序,用以计算结构载荷分布、约束条件复杂的等截面、变截面直立塔设备诸振型的自振频率。计算结果与GB150-98《钢制压力容器》中计算公式所得计算结构及实验数据比较,证明本方法有较高的计算精度,且比现有公式有更广泛的应用范围。 相似文献
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根据塔的连续条件,利用传递矩阵求解塔的振动方程,得到了塔设备固有频率的和不平衡响应振幅的计算方法,讨论了不同的设计参数对塔固有频率的影响。并将此方法应用在实际中。 相似文献
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利用大型有限元分析软件ANSYS对真空平板玻璃结构进行模态分析,按照真空玻璃国家标准,建立1000mm×1000mm真空平板玻璃模型,在ANSYS中设置材料属性及边界条件进行模态分析,在0~100000Hz频率范围内求解其1~10阶整体结构的固有频率及振型。另外,对相同尺寸下普通玻璃及中空玻璃模型进行模态分析,与真空平板玻璃固有频率及振型加以对比。结果表明:与普通平板玻璃及中空玻璃相比,真空平板玻璃每一阶固有频率最大,并且变形最小。说明真空平板玻璃刚度性能优先于普通玻璃及中空玻璃。为其整体设计及其制造提供了科学的依据,将有效预估结构的振动特性。 相似文献
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本文以笔者提出的局部虚功方程式的约束边界法为理论依据,建立高塔设备的约束悬臂梁模型和总体方程式,求解它的周期、振型和风荷载作用下的内力和变位。本法适用于任意变刚度、任意质量分布、底部为弹性嵌固(包含固定端)的石油化工高塔设备的静力和动力计算。当我们把塔与地基基础考虑成为一个体系时得到了与传统分析方法有明显不一样的结果,尤其是座落在较为软弱地基上的高塔,地基基础对它的静力和动力分析的贡献是很显著的,这一点应引起设备工程师的注意。笔者为本课题的求解,开发出程序TTSDC-1在PC-1500运算。 相似文献
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本文对工业中的排塔的自振特性进行了有限元分析,并通过排塔模型实验对有限元计算结果进行了验证。通过实验与计算结果分析,提出了计算排塔平面内振动一阶自动振率的简化公式。 相似文献
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对65台框架塔的自振周期和振型进行实测,发现基本振型与落地塔不同,塔体呈弯曲变形而框架部分呈剪切变形。根据实测自振周期进行数理统计分析提出自振周期经验公式。并用哈密顿原理,推导出计算振型的理论公式可供设计应用。 相似文献
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The use of a drum chute instead of the regular chute is proposed in coke sorting prior to classification. A method of calculating the optimal drum dimensions is outlined. The drum’s inclination is plotted as a function of the required number of drum rotations to which the coke is subjected. A simplified method is considered for determining the number of drum rotations to which the coke must be subjected in order to meet specified quality requirements. 相似文献
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Self‐adaptive piezoelectric ceramic vibration system based on asymmetric piezoelectric cantilever for energy harvesting
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Mingwei Fang Qingwei Liao Jiawen Wang Lei Qin Chao Zhong Di Zhang 《International Journal of Applied Ceramic Technology》2018,15(5):1268-1276
Micropower energy harvesting is one of key technologies for the micromation and practical development of wireless sensor and communication node networks. A self‐adaptive piezoelectric vibration system based on modified homogeneous strain asymmetric PZT piezoelectric ceramic cantilever beam for the micropower energy harvesting was designed and prepared. A vertical cantilever was designed at the first time to obtain the homogeneous state of stress which can largely increase the power output and energy harvesting efficiency of piezoelectric cantilevers. In order to achieve the self‐adaptive vibration, the asymmetric structure was adopted. Asymmetric cantilevers moved horizontally and changed the length of main cantilevers when affected by the variation in external frequency excitation, thus, the switching of resonant frequency was archived automatically without dissipating additional energy. 相似文献
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采用光纤布拉格光栅(FBG)对碳纤维增强复合材料(CFRP)的振动性能和损伤类型进行研究。采用落球击打碳纤维增强复合材料悬臂梁自由端,使复合材料悬臂梁产生谐振。通过测量复合材料悬臂梁的谐振频率,计算其阻尼损耗因子,得到无损伤碳纤维复合材料的振动性能。在此基础上,对碳纤维增强复合材料人为引入损伤,利用FBG测量其损伤状态下的谐振频率,依据谐振频率分析判断损伤类型。研究结果可对碳纤维增强复合材料的振动性能研究和损伤监测提供参考。 相似文献
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A model to evaluate the Energy Release Rate (ERR) of adhesives using the Double Cantilever Beam (DCB) specimen is described. The model accounts for the adhesive bond thickness and its material properties. The analysis, considered as an improvement to the built-in cantilever beam model, treats the adherend as a finite beam which is partly free and partly supported by an elastic foundation and the adhesive bond as a thin strip under prescribed displacement. The results show significant effect of the adhesive parameters on the total ERR and that the built-in cantilever model underestimates the ERR. In general, the contribution of the adhesive bond to the ERR increases for softer adhesives, shorter cracks and thicker bonds. 相似文献
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Measurement selection for on-line estimation of nonlinear wave models for high purity distillation columns 总被引:1,自引:0,他引:1
Shoujun Bian 《Chemical engineering science》2006,61(10):3210-3222
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Tae-Hak Park 《The Journal of Adhesion》1997,61(1):97-122
The purpose of this study is to verify the vibration and damping characteristics of a partially-layered elastic-viscoelastic-elastic structure both theoretically and experimentally.
The fourth-order differential equations of motion are derived for the transverse vibration of a three-layered sandwich beam with a viscoelastic (or adhesive) core layer. The transverse displacements of the constraining layer and the base beam are assumed to have different parameters. Both the transverse normal strain and the longitudinal shear strain of the viscoelastic core layer are included in the equations of motion. The solution to the resulting equations is obtained by solving a boundary value problem.
Numerical analysis of the equations and experimental measurements is illustrated by a cantilever beam in transverse vibration.
The vibration and damping effects of completely and partially covered beams are investigated and the effect of the position changes of partial coverage is intensively analyzed. 相似文献
The fourth-order differential equations of motion are derived for the transverse vibration of a three-layered sandwich beam with a viscoelastic (or adhesive) core layer. The transverse displacements of the constraining layer and the base beam are assumed to have different parameters. Both the transverse normal strain and the longitudinal shear strain of the viscoelastic core layer are included in the equations of motion. The solution to the resulting equations is obtained by solving a boundary value problem.
Numerical analysis of the equations and experimental measurements is illustrated by a cantilever beam in transverse vibration.
The vibration and damping effects of completely and partially covered beams are investigated and the effect of the position changes of partial coverage is intensively analyzed. 相似文献
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延迟焦化是目前国内、外渣油加工的重要手段之一,近几年其加工能力增长较快,随着一些新技术应用,焦炭塔系统运行的可靠性得以提升。笔者重点介绍焦炭塔本体设计的注意点及其系统新技术的应用情况,包含焦炭塔本体设计、焦炭塔阀门安全联锁控制系统、自动闸板式顶(底)盖机、水力除焦系统新技术的应用等。 相似文献