scholarly journals Modelling of Critical Velocities of the Cardan Mechanism using Transfer Matrix Method

Author(s):  
Petr Hrubý ◽  
Tomáš Náhlík

The presented paper focuses to rotating components of mechanical constructions. The problem of the spatial combined bending-gyratory vibration and calculation of the Eigen frequencies is studied. The model of Cardan Mechanism is solved by the transfer matrix method. Transfer matrices were derived for shaft, concentrated mass and elastic bearing. The physical and mechanical properties of each part of the mechanism are hidden in these matrices. A procedure for calculating Eigen frequencies was proposed.

Author(s):  
T. Önsay

Abstract The wave-mode representation is utilized to obtain a more efficient form to the conventional transfer matrix method for bending vibrations of beams. The proposed improvement is based on a phase-variable canonical state representation of the equation governing the time-harmonic flexural vibrations of a beam. Transfer matrices are obtained for external forces, step-change of beam properties, intermediate supports and for boundaries. The transfer matrices are utilized to obtain the vibration response of a point-excited single-span beam with general boundary conditions. The general characteristic equation and the transfer mobility of a single-span beam are determined. The application of the analytical results are demonstrated on physical structures with different boundary conditions. A hybrid model is developed to incorporate measured impedance of nonideal boundaries into the transfer matrix method. The analytical results are found to be in excellent agreement with experimental measurements.


2019 ◽  
Vol 86 (6) ◽  
Author(s):  
Jianshu Zhang ◽  
Xiaoting Rui ◽  
Junjie Gu

The transfer matrix method for linear multibody systems is capable of providing precise solutions for the dynamics of various mechanical systems, but it may also suffer from numerical instability in some cases, where serial chains with a large number of mechanical elements are involved or high-frequency harmonic responses are computed. Combining such a transfer strategy with the Riccati transformation yields the Riccati transfer matrix method (RTMM), which can help improve the numerical stability. According to the existing method, the conventional transfer matrices of all the mechanical elements should be obtained first; in other words, the existence of conventional transfer matrices is a prerequisite for the application of the RTMM. Thus, it seems that the RTMM is incapable of performing the dynamics analysis of linear multibody systems with indeterminate in-span conditions due to the nonexistence of the corresponding conventional transfer matrices. Observe that, for any state variables with indeterminate input–output relationships, the complementary state variables (the complementary state variable of a displacement is the corresponding internal force and vice versa) are identically equal to zero, and that the dimension of the Riccati transfer equation is only half of that of the conventional transfer equation. It reveals that the Riccati transfer equations for the connection points associated with indeterminate in-span conditions can be formulated directly, and that there is no need to rely on the conventional transfer equation. Two numerical examples are simulated and the computational results are compared with those obtained by the finite element method, which verifies the proposed method.


2011 ◽  
Vol 383-390 ◽  
pp. 4541-4545
Author(s):  
Xiao Di Wu ◽  
Gong Min Liu ◽  
Hao Chen

A pipe structure model composed of straight pipe, bent pipe, concentrated mass and flexible support was established. The axial, lateral and circumferential vibration of this model were taken into account in the paper. Then it was realized to calculate the natural characteristic of this pipeline in computer by using MATLAB language to program a series of procedures based on frequency-domain transfer matrix method. The calculation results were compared with the ANSYS simulation results, which illustrated the upper accuracy of frequency-domain transfer matrix method in calculating natural characteristic problems of pipeline structure system. At last, The pipeline system was analyzed with experimental modal method.By comparing the experimental results and computational results, relatively lesser error showed that computational results were reliable and frequency-domain TMM was verified to be valuable for practical application.


1987 ◽  
Vol 109 (3) ◽  
pp. 248-254 ◽  
Author(s):  
Moriaki Goya ◽  
Takuo Hayashi ◽  
Koichi Ito ◽  
Hiroshi Ohki

The transient responses of an elastic beam to large dynamic deformations were analyzed numerically, using the transfer matrix method. Geometrically nonlinear differential equations were linearized by introducing increments of unknown functions, and the resulting linear equations were approximated by finite difference equations. A field transfer matrix was introduced for the analyses of large deformations; this determined the relationship between the incremental state vectors at both ends of the elastic segments. The Newmark β formulation was chosen to approximate the equation of motion for concentrated masses. A concentrated mass point transfer matrix and an inhomogeneous vector were introduced for analyses of the transient responses of the beams. A superposition scheme for the transfer matrix method was proposed as an effective means of obtaining a solution satisfying the boundary conditions at both ends of the beam.


2009 ◽  
Vol 23 (20n21) ◽  
pp. 4138-4149 ◽  
Author(s):  
STEPHEN A. WELLS ◽  
CHI-TIN SHIH ◽  
RUDOLF A. RÖMER

There is increasing evidence that DNA can support a considerable degree of charge transport along the strand by hopping of holes from one base to another, and that this charge transport may be relevant to DNA regulation, damage detection and repair. A surprisingly useful amount of insight can be gained from the construction of simple tight-binding models of charge transport, which can be investigated using the transfer-matrix method. The data thus obtained indicate a correlation between DNA charge-transport properties and the locations of cancerous mutation. We review models for DNA charge transport and their extension to include more physically realistic diagonal-hopping terms.


2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Bin He ◽  
Xiaoting Rui ◽  
Huiling Zhang

The application of Transfer matrix method (TMM) ranges from linear/nonlinear vibration, composite structure, and multibody system to calculating static deformation, natural vibration, dynamical response, and damage identification. Generally TMM has two characteristics: (1) the TMM formulae share similarity to the chain mechanics model in terms of topology structure; then TMM often is selected as a powerful tool to analyze the chain system. (2) TMM is adopted to deal with the problems of the discrete system, continuous system, and especial discrete/continuous coupling system with the uniform matrix form. In this investigation, a novel TMM is proposed to analyze the natural vibration of the tree system. In order to make the TMM of the tree system have the two above advantages of the TMM of the chain system, the suitable state vectors and transfer matrices of the typical components of the tree system are constructed. Then the topology comparability between the mechanics model and its corresponding formulae of TMM can be adopted to assembling the transfer matrices and transfer equations of the global tree system. Two examples of natural vibration problems validating the method are given. The formulation of the proposed TMM is mathematically intuitive and can be held and applied by the engineers easily.


1993 ◽  
Vol 07 (20n21) ◽  
pp. 3489-3500 ◽  
Author(s):  
R.J. BAXTER

We consider the star-triangle relation and the form of its solutions. We present some simple parametrizations of the weight functions of the three-state chiral Potts model. This model does not have the “difference property”: we discuss the resulting difficulties in attempting to use the corner transfer matrix method for this model.


2019 ◽  
Vol 8 (2) ◽  
pp. 3620-3626

The report presents a new method for linear analysis of continuous curved flat bar, subject to any load in space. This method is a combination of improving the expression of the load and displacement at the two ends of the curved bar element of the Transfer Matrix Method and Finite Element Method (TMMFEM), called the Matrix Method transfer improvements. The research results are to build math problems and programming with Matlab, verify with the results according to SAP2000 oftware and « Strength of materials » documents


1975 ◽  
Vol 19 (01) ◽  
pp. 57-61
Author(s):  
W. D. Pilkey ◽  
J. K. Haviland ◽  
P. Y. Chang

It is shown that the finite-element method can be efficiently employed in the analysis of line structures, in particular, ship structures, if it is combined with the transfer matrix method. Advantage is taken of the finite element method's structural modeling capability in representing complicated substructures. The substructures are pieced together along the length of the structure using transfer matrices. It is demonstrated that this approach can be superimposed on available large scale finite-element systems to improve their efficiency and increase their capabilities.


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