Tài liệu Cơ Khí - Chế Tạo Máy

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: 575 | 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: 436 | 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: 496 | 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: 495 | 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: 480 | 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: 432 | Lượt tải: 0
Multiple crack identification in stepped beam by measurements of natural frequencies
In the present study the well known Rayleigh Quotient has been developed for multi-stepped beam with arbitrary number of cracks and boundary conditions. This is an explicit expression of natural frequencies in term of crack parameters that provides a simplified method for calculating natural frequencies of the beam. Moreover, the Rayleigh Quoti...
16 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 525 | Lượt tải: 0
Free vibration analysis of four parameter functionally graded plates accounting transverse shear mode
Classical, symmetric and asymmetric profiles are generated by the suitable assumption of value of power law parameters. It was noticed symmetric profiles exhibits maximum frequency value for certain value of power law exponent (p > 1) and this tendency is irrespective of the plate thickness and boundary condition. Variation of single parameter in ...
18 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 523 | Lượt tải: 0
Parameter optimization of tuned mass damper for three-Degree-of-freedom vibration systems
In this paper, the sequential quadratic programming (SQP) method is used to calculating parameter optimization of the tuned mass damper (TMD) for three-degree-offreedom vibration systems. The following concluding remarks have been reached: - If the TMD is attached to the vibration source (excited force or kinematical excitement), the effect of vib...
12 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 422 | Lượt tải: 0
Spectral analysis of multiple cracked beam subjected to moving load
load the cracks occurred to symmetric positions affect not symmetrically on the response; amplitude of forced vibration is not monotony increasing with growing number of cracks. The proposed method can be used for dynamic analysis in the case of more complicated moving load and crack detection problem by measurement of dynamic response of beam-l...
12 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 499 | Lượt tải: 0