共查询到20条相似文献，搜索用时 31 毫秒
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ＩＮＴＲＯＤＵＣＴＩＯＮＡｓｋｎｏｗｎ ,ｔｈｅｒｍａｌｂｅｈａｖｉｏｒｓｏｆｓｔｒｕｃｔｕｒｅｓｍｕｓｔｂｅｃｏｎｓｉｄｅｒｅｄｉｎｍａｎｙｓｉｔｕａｔｉｏｎｓ.Ｓｔｕｄｙｏｆｔｈｅｒｍａｌｅｆｆｅｃｔｏｎｄｅｆｏｒｍａｔｉｏｎｓａｎｄｓｔｒｅｓｓｅｓｏｆ 相似文献
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The thermal behavior of a thick transversely isotropic FGM rectangular plate was investigated within the scope of three-dimensional
elasticity. Noticing many FGMs may have temperature-dependent properties, the material constants were further considered as
functions of temperature. A solution method based on state-space formulations with a laminate approximate model was proposed.
For a thin plate, the method was clarified by comparison with the thin plate theory. The influences of material inhomogeneity
and temperature-dependent characteristics were finally discussed, through numerical examples.
Project (No. 10002016) supported by National Natural Science Foundation of China 相似文献
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ZHANG Zhi ming ZHU Li jin YU Jun 《上海大学学报(英文版)》1999,3(3):227-233
Ｎｏｍａｎｃｌａｔｕｒｅ ｂｉｊ,Ｂｉｊ（ｉ,ｊ＝ｘ,ｙ） ｂｅａｒｉｎｇｄａｍｐｉｎｇａｎｄｎｏｎｄｉｍｅｎｓｉｏｎａｌｄａｍｐｉｎｇｃｏｅｆｆｉｃｉｅｎｔｓ,Ｂｉｊ＝ｂｉｊΨ３ｍｉｎ／（２ｌμ） ｃｍｉｎｍｉｎｉｍｕｍｒａｄｉａｌｃｌｅａｒａｎｃｅｏｆｂｅａｒｉｎｇｄｄｉａｍｅｔｅｒｏｆｂｅａｒｉｎｇｅｕ,Ｅｕｅｃｃｅｎｔｒｉｃｉｔｙａｎｄｒｅｌａｔｉｖｅｅｃｃｅｎｔｒｉｃｉｔｙｏｆｍａｓｓｃｅｎｔｅｒｏｆｒｏｔｏｒ,ｒｅｓｐｅｃｔｉｖｅｌｙ,Ｅｕ＝ｅｕ／ｃｍｉｎＦｓｔａｔｉｃｌｏａｄｏｎｂ… 相似文献
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通过有限元软件ANSYS构建非线性数值模型,并利用现有试验数据进行模型准确性验证。分析了板件宽厚比、截面尺寸效应以及是否约束某一主轴方向位移对构件稳定承载力的影响,发现三者影响均可不予考虑。在大规模参数分析的基础上,本文建议对于6061-T6,几何缺陷系数中的两个参数分别取和,对于6061-T4建议取和。对比中、欧规范计算结果发现,该建议与试验及参数分析结果具有更好的吻合性,满足计算精度和安全度的工程设计要求。 相似文献
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《浙江大学学报(A卷英文版)》2021,(1)
To improve the low-frequency vibration reduction effect of a steel spring floating slab track(FST), nonlinear quasizero-stiffness(QZS) vibration isolators composed of positive stiffness elements(PSEs) and negative stiffness elements(NSEs) were used to support the FST. First, considering the mechanical characteristics of the nonlinear QZS vibration isolators and the dynamic displacement limit(3 mm) of the FST, the feasible parameter groups were studied with the nonlinear stiffness variation range and bearing capacity as evaluation indices. A vertical vehicle quasi-zero-stiffness floating slab track(QZS-FST) coupled dynamic model was then established. To obtain a reasonable nonlinear stiffness within a few millimeters, the original length of the NSEs must be analyzed first, because it chiefly determines the stiffness nonlinearity level. The compression length of the NSEs at the equilibrium position must be determined to obtain the low stiffness of the floating slab without vehicle load. Meanwhile, to meet the dynamic displacement limit of the FST, the PSE stiffness must be increased to obtain a higher stiffness at the critical dynamic displacement. Various stiffness groups for the PSEs and NSEs can provide the same dynamic bearing capacity and yet have a significantly different vibration reduction effect. Excessive stiffness nonlinearity levels cannot effectively improve the vibration reduction effect at the natural frequency. Furthermore, they also significantly amplify the vibrations above the natural frequency. In this paper, the vertical vibration acceleration level(VAL) of the floating slab and the supporting force of the FST can be decreased by 6.9 dB and 55%, respectively, at the resonance frequency. 相似文献
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船舶板架结构除了受到自身重力和设备重力作用外,还受到激振力的作用。应用大型有限元软件ANSYS软件对部分船体板架在受设备激振力和不受设备激振力两种情况进行计算,并就计算结果进行对比分析。结果显示,往往被我们忽视的激振力对船舶板架结构强度的影响不容忽视。 相似文献
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史朝辉 《廊坊师范学院学报(自然科学版)》2012,12(1):51-53
利用双水平QCISD（T）/6-311＋＋G（d,p）//B3LYP/6-311＋G（d,p）量子力学计算方法研究了二甲基硫和溴原子反应的微观反应动力学机理,该反应有3个可能的反应通道。通过计算得到DMS和Br反应生成复合物的平衡常数以及R1,R3在200~2000K温度范围内的反应速率常数,和实验值吻合较好。 相似文献
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目前空气弹簧已广泛应用于车辆悬架系统中。车辆动力学性能主要取决于悬架参教的匹配。悬架参教的精确性将直接影响车辆行驶的平稳性。基于热力学理论和气体状态方程式，建立了带附加气室的空气弹簧的统一力学模型，对其数学模型进行了求解，得出了其瞬态响应和稳态响应的理论值，求出了空气弹簧的自振频率和粘滞阻尼系数。为设计制造空气弹簧奠定了一定的理论基础。 相似文献
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用直接从头算动态学方法对CH2N＋HONO→CH2NH＋NO2反应进行了研究.用BH＆HLYP/6-31＋G（d,p）方法对所有稳定结构和过渡态的几何结构进行了优化,并用内禀反应坐标方法计算了最小能量路径（MEP）.在QCISD（T）/6-311＋G（2df,2pd）理论水平上对所有结构的能量进行了进一步校正.用变分过渡态理论（CVT）在考虑小曲率隧道（SCT）校正的水平上计算了200～2500K温度范围内标题反应的热速率常数,计算结果表明,上述温度范围内热速率常数有正的温度效应,计算结果与文献数据能够很好地吻合. 相似文献
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Social vulnerability assessments are largely ignored when compared with biophysical vulnerability assessments. This is mainly due to the fact that there are more difficulties in quantifying them. Aiming at several pitfalls still existing in the Hoovering approach which is widely accepted, a suitable modified model is provided. In this modified model, the integrated vulnerability is made an analogy to the elasticity coefficient of a spring, and an objective evaluation criterion is established. With the evaluation criterion, the assessment indicators of social vulnerability are filtered and their weight assignments are accomplished. There is an application in the city of Changsha where floods occur often. With the relative data from the PICC Hunan Province Branch, a generalized regression neural network model is established in Matlab 7.0 and used to evaluate a company's flood social vulnerability index (SoVI). The results show that the average flood social vulnerability in Yuhua district is the highest, while Yuelu district is the lowest. It is good for disaster risk management and decision-making of insurance companies. 相似文献
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在弹性梁与磁弹性力学理论的基础上,应用动力学方法建立电磁场和温度场耦合作用下的载流梁的非线性热磁弹性耦合振动方程。应用Galerkin法导出了系统受电磁力和热力共同作用的非线性振动微分方程组。通过数值计算,给出了不同系统参数下的系统振动的时程图和相图。 相似文献
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何利平 《晋城职业技术学院学报》2011,4(5):73-75
考虑一类具有正负系数的时滞微分方程x（＇t）＋1tlntni=1Σpix（tα）i-1tlntni=1Σqix（tβ）i=0,其中0〈αi〈1,0〈βi〈1,pi〉0,qi≥0是常数,证明了方程所有解振动的一个充分条件为αi〈βi,ni=1Σpi〉ni=1Σqi,ni=1Σqilnβiα≤1,ni=1Σ（pi-qi）ln1α〉1e其中α=max{α1,α2,…,αn≤≤}. 相似文献
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社会历史发展具有客观规律性 ,试图以历史主体的选择性和历史过程的非线性来否定历史规律的观点是站不住脚的。以波普尔为代表的非决定论思潮的泛起是有历史背景、认识根源和社会原因的。这股非决定论思潮尽管无法否定决定论 ,但是它所产生的负面影响是不能忽视的。在这种情况下 ,重新确立辩证决定论的思想对建设有中国特色的社会主义具有重大的理论意义和实践意义 相似文献
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Cubic algebraic hyperbolic （AH） Bezier curves and AH spline curves are defined with a positive parameter a in the space spanned by {1, t, sinht, cosht}. Modifying the value of a yields a family ofAH Bezier or spline curves with the family parameter α. For a fixed point on the original curve, it will move on a defined curve called ＂path of AH curve＂ （AH Bezier and AH spline curves） when a changes. We describe the geometric effects of the paths and give a method to specify a curve passing through a given point. 相似文献
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运用基于密度泛函的第一原理方法对具有钙钛矿结构BaTiO3的热物理性能进行了计算,得到了BaTiO3的晶格常数、弹性性能和热物理性能,并对电子结构特性进行分析。计算结果表明：计算所得的晶格常数和实验值符合的很好,计算了钙钛矿结构的BaTiO3的单晶弹性常数,并利用Viogt—Reuss—Hill方法获得了多晶的体积模量、剪切模量、杨氏模量、泊松比以及弹性各向异性比。由B／G的比值可知,钙钛矿结构的BaTiO3呈脆性性质。能带结构和电子态密度的计算表明,钙钛矿结构的BaTi03是一个具有1．59eV能隙的间隙半导体。利用准谐德拜模型．计算了该化合物的热熔和热膨胀系数随温度和压强的变化关系。 相似文献
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陈英杰 《海南师范大学学报(社会科学版)》2014,(5):95-99
1943年春夏间,宋美龄在美访问引起轰动,返华时带回罗斯福邀请蒋介石参加盟国领袖会议的口信,在几经联系后,终于决定于1943年冬,在埃及开罗召开中美英三国领袖会议.宋美龄偕同蒋介石共赴开罗,以其娴熟的英语能力,周旋于美英高层,争取中方权益,其所扮演的角色至为重要,对提升中国的民心士气和国际形象,亦有莫大帮助.文章将试图运用蒋档和相关史料,探讨宋美龄在开罗会议所扮演的角色与作用. 相似文献
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用密度泛函理论B3LYP方法,在6-311G(d,p)基组下,优化得到C2(a3Πu)+C2H6→C2H+C2H5反应各驻点(反应物、过渡态和产物)的几何构型,对其进行振动分析,并计算了它们的能量.在CCSD/6-311G(d,p)水平下单点能计算得到的反应势垒为24.47kJ/mol.采用传统过渡态理论,计算了温度范围50K～2000K的反应速率常数.实验结果表明,随着反应温度的升高,反应速率逐渐升高,反应的平均活化能也随着温度的不断升高而不断增大. 相似文献