摘要:

AbstractDynamical dissipative or nondissipative discrete systems under constant directional (conservative) step loading described by nonlinear autonomous Ordinary Differential Equations (ODEs) are considered. Attention is restricted on gradient structural systems which under the same loading applied statically exhibit a branching point critical response bifurcating from a trivial prebuckling path. The connection of static bifurcations and stability with the corresponding dynamic bifurcations and stability are comprehensively discussed after a thorough investigation of the structural form of the Jacobian matrix and its characteristic equation. The relation of the eigenvalues of the statical system with those of the dynamical system associated with the Jacobian matrix is examined at the precritical, critical and postcritical stage. This enables us to establish very simple stability conditions (related basically to the sign of second variation of the total potential energy) compared to those of Routh‐Hurwit

ISSN:0044-2267    

DOI:10.1002/zamm.19930730302

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractDie Aufgabenstellung der experimentellen Modalanalyse liegt in der Identifikation der Eigenschwingungsgrößen eines meßtechnisch untersuchten Objekts. Im Rahmen eines Konzepts zur Durchführung experimenteller Modalanalysen an Werkzeugmaschinen mit leicht transportierbarer Hardware wird ein Algorithmus zur Identifikation modaler Parameter anhand gemessener Übertragungsfrequenzgänge vorges

ISSN:0044-2267    

DOI:10.1002/zamm.19930730303

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19930730305

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractA theorem of Arnol'd and Gallavotti states that by a suitable potential of increasing rigidity a mechanical system with conservative forces can be constrained to a hypersurface of the configuration space and its motion approaches a solution of the reduced Lagrangian equation. In this paper the theorem will be generalized to time‐ and velocity‐dependent forces including time‐dependent constraints and proved with the aid of the method of averaging. This technique also allows us to identify the constraint force as the averaged negative gradient of the constraint pote

ISSN:0044-2267    

DOI:10.1002/zamm.19930730306

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19930730309

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe free‐boundaryMHDequilibrium is considered for plane symmetry and constant current profile. It is shown that there are solutions with an x‐point at the plasma‐vacuum interface, such that the plasma fills one of the four sectors formed by the separatrix. Such “plasma corners” are a common feature of modern fusio

ISSN:0044-2267    

DOI:10.1002/zamm.19930730310

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19930730313

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe influence of an artificial viscosity on the stability of numerical solution of transonic flows with shock waves is investigated. The variational principle with dissipation introduced through a physical viscosity is derived, and a simplified relation describing the stabilizing influence of the dissipative process is presented. The numerical solution of the potential equation by FEM is examined and compared with the formulation using the variational principle. The correspondence between physical viscosity μ and artificial viscosity μnumis shown both qualitatively and quantitatively. The necessary amount of artificial viscosity is investigated analytically and the results are compared with numerical experiment

ISSN:0044-2267    

DOI:10.1002/zamm.19930730314

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19930730315

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19930730316

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY