Tài liệu Kỹ Thuật - Công Nghệ

Determination of mode shapes of a multiple cracked beam element and its application for free vibration analysis of a multi-Span continuous beam
The article presents some results on the determination of vibration shape functions of a multiple cracked elastic beam element, where the multiple cracked beam element is modeled as an assembly of intact sub-segments connected by massless rotational springs. Also, algorithms and computer programs are established for analyzing changes in mode shap...
13 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 532 | Lượt tải: 0
Buckling of double-Walled carbon nanotubes
In this study it has been demonstrated that the finite difference method can be successfully applied to buckling of double-walled carbon nanotubes since it yields extremely reliable results. The best approximation for the clamped-free DWCNT is 5.590 (Tab. 1), and the best approximation for the simply supported at both ends is 22.236 (Tab. 2). T...
8 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 502 | Lượt tải: 0
An effective algorithm for reliability-Based optimization of stiffened mindlin plate
The paper presents an approach to establish and solve two reliability-based design optimization problems for Mindlin plate stiffened by Timoshenko beams. In the first problem, static analysis is considered. The objective function is the minimum of the strain energy with constraints on displacement. In the second problem, free vibration analysis i...
14 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 437 | Lượt tải: 0
Numerical analysis of free vibration of cross-Ply thick laminated composite cylindrical shells by continuous element method
This article has succeeded in constructing the CEM model and in creating a computing program by Matlab to solve the problem of vibration of thick composite cylindrical shells using Continuous Element Method. Through different comparisons with the published results and with the other calculation methods, the obtained results are very satisfied. N...
16 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 433 | Lượt tải: 0
A co-Rotational beam element for geometrically nonlinear analysis of plane frames
In this paper, a co-rotational beam element for geometrically nonlinear analysis of plane frames has been formulated. The shallow arch expression was adopted for the local strain and the exact polynomials obtained from the field consistence approach were employed as interpolation functions for the transversal displacement and sectional rotation....
17 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 546 | Lượt tải: 0
Postbuckling of functionally graded cylindrical shells based on improved donnell equations
This paper presents an analytical approach to investigate buckling and postbuckling behaviors of FGM circular cylindrical shells subjected to axial compressive load, uniform external pressure accounting for the effects of temperature conditions. Equilibrium equations are established within the framework of improved Donnell shell theory taking int...
17 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 424 | Lượt tải: 0
A method of skin frictional resistant reduction by creating small bubbles at bottom of ships
Small bubble injection method has an effect on reduction ship resistance, and therefore, the ship energy consumption is reduction, correlatively. In calm water, the small bubble injection method has a good effect on a ship at an interval identified operating speed. In this research, experiments were carried out with a 20000 ton model ship, then,...
11 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 486 | Lượt tải: 0
Generalized pseudo inverse kinematics at singularities for developing five-Axes cnc machine tool postprocessor
The paper presents an analytical scheme for analyzing the singular configuration of general five-axes CNC machine This is useful for checking the singularities of any specific machine. The singular configuration problem causing big machining error is effectively solved and the proposed algorithm shows its advantage for producing smooth cutter tr...
11 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 485 | Lượt tải: 0
Nonlinear buckling and post-Buckling of eccentrically stiffened functionally graded cylindrical shells surrounded by an elastic medium based on the first order shear deformation theory
This paper presents an analytical solution to investigate the buckling and postbuckling behavior of ES-FGM cylindrical shells surrounded by an elastic medium subjected to mechanical compressive loads and external pressures. Theoretical formulations are based on the smeared stiffeners technique and the first-order shear deformation theory. The an...
16 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 469 | Lượt tải: 0
Construction of bounds on the effective shear modulus of isotropic multicomponent materials
The trial polarization fields (6), (29) used in this paper depend on 2N − 2 free parameters [i.e., 2N parameter aα, bα restricted by 2 constraints (10), (11)], hence are more general than the Hashin-Shtrikman ones used [3–5], which contain just 2 free parameters. Therefore the new bounds are more restricting in the cases N ≥ 3. We remind the part...
11 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 423 | Lượt tải: 0