共查询到20条相似文献,搜索用时 15 毫秒
1.
A method for determining the natural frequencies and modes of ribbed shallow shells with rectangular planform on an elastic
foundation is developed. The method takes into account the discrete arrangement of the ribs. A shallow spherical shell with
square planform is considered as example to analyze the effect of the number of ribs and the Winkler and Pasternak coefficients
of subgrade reaction on the natural frequencies and modes. It is recommended to take into account the discrete arrangement
of ribs when they are few 相似文献
2.
A rectangular plate reinforced with longitudinal ribs is considered. The influence of the discrete ribs on the wavenumbers
of harmonic waves propagating along the ribs is investigated. The effect of the stiffness parameters of the ribs on the natural
frequencies and modes of a cross-ribbed plate is studied
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 2, pp. 65–78, February 2006. 相似文献
3.
Open cylindrical shells reinforced with quasiregular sets of longitudinal ribs and hinged at all edges are considered. The
effect of the discrete arrangement and number of ribs on the critical stresses that cause instability under longitudinal compression
and on the minimum natural frequencies of vibrations is examined. Numerical results are analyzed 相似文献
4.
The paper studies the effect of the discrete arrangement of ribs and their number on the number of dispersion curves for harmonic waves that have a deflection node on a rib's axis and propagate along a cylindrical shell. It is found out that these curves split and the distance between the split curves depends strongly on the torsional stiffness of the ribs 相似文献
5.
The influence of discrete longitudinal ribs on harmonic waves in cylindrical shells is studied by numerical examples. It is shown that the presence of discrete ribs is manifested as an increased number and changed shape of the dispersion curves 相似文献
6.
A technique is proposed to determine the natural frequencies of rib-reinforced cylindrical shells with low shear stiffness. The equations of motion based on the Timoshenko model are used. The influence of the transverse shear moduli of the shell and ribs on the minimum natural frequencies and corresponding modes is studied by way of numerical examples. It is shown that the effect of the discrete ribs is different from that predicted by the classical theory of ribbed shells__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 4, pp. 66–74, April 2005. 相似文献
7.
E. K. Ankyanets 《International Applied Mechanics》2005,41(10):1177-1181
The vibrations of a cylindrical shell reinforced with circular ribs attached to it by means of discrete elastic elements are
studied. The problem is solved by the finite-element method. The shell and ribs are modeled by a plane four-node finite element,
which is a combination of a four-node plane stress element and a four-node flexural element. The effect of the stiffness of
the elastic elements on the natural frequencies and modes is examined
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 10, pp. 108–113, October 2005. 相似文献
8.
The exact solutions of the equations of motion derived under refined theories of shells and ribs based on the Timoshenko model
are used to plot dispersion curves for harmonic waves propagating along a cylindrical shell reinforced with discrete longitudinal
ribs
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 37–41, May 2006. 相似文献
9.
The paper gives exact solutions to the stability and vibration problems for nonclosed circular cylindrical shells hinged along
the longitudinal edges and reinforced with a regularly arranged discrete longitudinal ribs. These problems are also solved
approximately in the cases of regularly and quasiregularly arranged ribs
__________
Translated from Prikladnaya Mekhanika, Vol. 44, No. 1, pp. 20–27, January 2008. 相似文献
10.
This paper reviews studies and analyzes results on the effect of discrete ribs on the dynamic characteristics of rectangular
plates and cylindrical shells. Use is made of the vibration equations derived from the classical theories of beams, plates,
and shells. The effect of Pasternak’s elastic foundation on the critical velocities of a structurally orthotropic model of
a ribbed cylindrical shell is determined. Nonstationary problems are solved for perforated and ribbed shells of revolution
filled with a fluid or resting on an elastic foundation and subjected to moving or impulsive loads. Results from studies of
the behavior of sandwich shell structures under impulsive loads of various types are presented 相似文献
11.
The exact solution for the inhomogeneous system of equilibrium equations for open circular cylindrical shells reinforced with
a quasi-regular system of discrete ribs is obtained. The dependence of stress–strain state of semi-infinite shells on the
distance from the loaded edge is analyzed. 相似文献
12.
A technique is proposed to determine the fundamental frequencies of vibrations of rectangular plates strengthened by an orthogonal
system of ribs. The necessity of allowing for the discrete arrangement of ribs is demonstrated by numerical examples.
S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika,
Vol. 36, No. 7, pp. 117–122, July, 2000. 相似文献
13.
P. Z. Lugovoi V. F. Meish B. P. Rybakin G. V. Sekrieru 《International Applied Mechanics》2006,42(5):536-540
Dynamic problems for cylindrical shells reinforced with discrete ribs are examined. A numerical algorithm based on Richardson
extrapolation is developed. Specific problems are solved, and the results are analyzed
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 50–56, May 2006. 相似文献
14.
The analytical method developed to determine the upper and lower critical stresses is applied to cylindrical shells reinforced
with stringers and rings. Buckling modes typical of shells reinforced with discrete ribs are considered. The minimum critical
loads are determined and compared with available experimental data. Perfect and imperfect ribbed shells with high-modulus
reinforcement are studied. It is proved that the effect of small axisymmetric imperfections in such shells is not so drastic
as in isotropic shells. Ribs made of a high-modulus material can enhance the stability of shells by a factor of tens 相似文献
15.
V. A. Zarutskii 《International Applied Mechanics》2000,36(4):545-550
The exact solution of the equations of neutral equilibrium is derived. The effect of the discrete arrangement of ribs on the
behavior of the characteristics of the stress-strain state with distance from the plate edge is analyzed. The conditions of
applicability of the theory of structurally orthotropic plates are formulated.
The study was carried out in accordance with Project No. 614 of the Ukrainian Scientific and Technological Center.
S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika,
Vol. 36, No. 4, pp. 132–136, April, 2000. 相似文献
16.
The effect of the stiffness of ribs on the minimum natural frequencies and critical stresses of axially compressed open cylindrical
shells reinforced with a quasiregular set of longitudinal ribs is analyzed by way of numerical examples. It is shown that
the earlier discovered phenomenon of abrupt decrease in the minimum frequencies is independent of rib stiffness for certain
modes and a small number of ribs 相似文献
17.
A method is proposed to study the influence of discrete ribs on the dispersion curves for harmonic waves propagating along the directrix of a simply supported cylindrical shell reinforced with rings. A numerical example is considered to demonstrate the necessity of accounting for this factor, the possibility of using a simplified formulation of the problem, and the necessity of accounting for the asymmetry of rib arrangement about the median surface of the shell 相似文献
18.
V. A. Zarutskii 《International Applied Mechanics》2000,36(5):559-585
The results of stability analysis of ribbed shells performed on the basis of the techniques developed by I. Ya. Amiro and
his followers are reviewed. Attention is focused on the features of their buckling due to the discrete arrangement of ribs.
S.P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika,
Vol. 36, No. 5, pp. 3–31, May, 2000. 相似文献
19.
运用大型有限元软件Patran/Nastran分析了大开口复合材料加筋壁板的稳定性,并对不同加筋方式下壁板屈曲特征值和屈曲模态图进行了比较。结果表明:补强提高了大开口复合材料壁板的稳定性,但往往无法达到很好的效果,需要通过加筋改善其稳定性;加筋复合材料壁板稳定性较原有模型有较大提高;加筋大开口复合材料壁板屈曲特征值随筋条距开口中心距离的增加而减小,其屈曲分界线均位于筋条布置处;纵筋大开口复合材料加筋壁板一阶屈曲特征值为2.13,而横筋只达到1.08;纵筋布置对复合材料壁板稳定性影响明显高于横筋布置,可在实际工程应用中适当增加纵筋的布置。 相似文献
20.
We obtain exact and approximate solutions to buckling problems for circular cylindrical open shells hinged at all edges and
quasiregularly reinforced with discrete longitudinal ribs. It is shown that analogous solutions to natural-vibration problems
for such shells can easily be found
Translated from Prikladnaya Mekhanika, Vol. 44, No. 12, pp. 83–92, December 2008. 相似文献