ISSN:0044-2267    

DOI:10.1002/zamm.19970770602

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractAutoparametric systems represent a special class of nonlinear systems. Such a system has at least two parts, i.e. two degrees of freedom at least. The first part — the oscillator — vibrates due to external or parametric excitations or due to self‐excitation. A typical feature is represented by the existence of the semi‐trivial solution, which means that only the oscillator vibrates. Under certain conditions the semi‐trivial solution is unstable, and autoparametric resonance is induced. Several examples of these systems together with a survey of the investigation results are presented. Typical properties like saturation effect and the occurrence of non‐periodic vibration are illustrated

ISSN:0044-2267    

DOI:10.1002/zamm.19970770603

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA method for dealing with the numerical integration of non‐smooth mechanical dynamical systems is presented. This method is based on the integration of piecewise smooth parts and piecing these parts together with appropriate transition conditions. A distinguishing characteristic of this method is that it can deal with very close transitions. The method is applied to a forced friction oscillator with one degree of freedom, and a system of two coupled non‐linear oscillators in which one oscillator has an amplitude‐limiting

ISSN:0044-2267    

DOI:10.1002/zamm.19970770604

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770607

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThis paper is concerned with the numerical algorithms for the macromechanical analysis of a ceramic bar in which account is taken of mechanical, electrical, and thermal fields. In the first part of the paper, a hierarchic system of one‐dimensional equations of the thermopiezoceramic bar is deduced by a direct method of integration from the three‐dimensional equations of thermopiezoelectricity. Also, in a similar way, the method of moments is described for the macromechanical analysis. The second part is addressed to a direct method of solution which is essentially based on Kantorovich's method, as an alternative, for the macromechanical analysis. The resulting equations incorporate all the significant effects of ceramic bar under a general state of mechanical, electrical, and thermal loads. They accommodate the extensional, flexural, and torsional as well as coupled motions of thermopiezoceramic bar at both low and high frequencies. Lastly, in the third part, attention is confined to the cases involving special fields, motions, and material propert

ISSN:0044-2267    

DOI:10.1002/zamm.19970770608

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770610

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA perturbation method based on the static stability criterion associated with the vanishing of the total potential energy on a certain equilibrium point on the unstable postbuckling path is presented for the determination of lower bound dynamic buckling loads of imperfection‐sensitive structures under step load of infinite duration. Attention is focused on the effect of various possible sources of structural imperfections on the dynamic buckling strength of perfect structures. Under the assumption that the effect of structural imperfections is of the first order, the method can give any desired higher‐order approximation to the lower bound dynamic buckling loads and the corresponding displacements without solving the system of differential equations of motion numerically. Especially, the method applies to finite‐degree‐of‐freedom systems as well as continuous ones. The application of the method is illustrated on two examples. The results demonstrate the significant effect of other imperfection sources, besides the shape imperfections having the shape of the classical buck

ISSN:0044-2267    

DOI:10.1002/zamm.19970770611

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe electrohydrodynamic flow of a fluid in an “ion drag” configuration in a circular cylindrical conduit is governed by a non‐linear second‐order ordinary differential equation. The degree of non‐linearity in this equation is determined by a nondimensional parameter α and the equation can be approximated by two different linear equations for very small or very large values of α respectively. Perturbation solutions of the fluid velocities for α ≪ 1 and α ≫ 1 are developed. A Gauss‐Newton finite‐difference solver combined with the continuation method and a Runge‐Kutta shooting method are used to provide numerical results for the fluid velocity over a large range of values of α. Both numerical and analytical results are compared in order to establish the range of validity for th

ISSN:0044-2267    

DOI:10.1002/zamm.19970770612

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770614

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe topological degree of a continuous mapping is implemented for the calculation of the total number of the simple real zeros within any interval of the Bessel functions of first and second kind and their derivatives. A new algorithm, based on this implementation, is given for the localization and isolation of these zeros. Furthermore, a second algorithm is presented for their computation employing a modified bisection method. The only information required for this computation is the algebraic signs of function values. Moreover, lower and upper bounds of a zero can also be obtained.

ISSN:0044-2267    

DOI:10.1002/zamm.19970770615

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY