ISSN:0044-2267    

DOI:10.1002/zamm.19970770702

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThis paper concerns the study of superpotential laws in analytical mechanics which may be derived from generally non‐everywhere differentiable energy functions through subdifferentiation. A generalization of d'Alembert's principle is proposed dealing with problems involving unilateral constraint

ISSN:0044-2267    

DOI:10.1002/zamm.19970770703

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770704

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractDie folgenden Ausführungen wurden angeregt durch eine — scheinbar vergessene(!) — ArbeitPaul Stäckelsüber das Prinzip des kleinsten Zwanges. Es zeigt sich, daß für zahlreiche Fälle, die auch in ihrer praktischen Anwendung von Relevanz sind, das d'Alembert/Lagrangesche Prinzip versagt, während das Gaußsche Prinzip ohne weiteres brauchbar ist. Wie es scheint, wurde diese Erkenntnis in der neueren Forschung bislang nirgendwo rezipiert. Die genannte Arbeit enthält ferner einen Hinweis auf den historischen Ursprung einer für die Mehrkörperdynamik besonders nützlichen Form der Lagrangeschen Gleichungen. Diese ist Gegenstand des Zweiten Teil

ISSN:0044-2267    

DOI:10.1002/zamm.19970770707

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractApproximate optimal design and weight minimization problems are proposed, making use of mixed‐interpolated finite elements methods. The design variables — i.e., the thickness of the plate and the stiffness of the foundation are approximated by piecewise affine functions. The solvability of the approximate problems is proved and some convergence analysis is presen

ISSN:0044-2267    

DOI:10.1002/zamm.19970770708

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770710

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractIn this paper we propose a continuum model of a moving transition layer smoothly separating two different solid phases of a certain elastic material continuum and we investigate some necessary conditions to its existence and propagation. An application of this model to the analysis of wave propagation in micro‐damaged media with open‐ and closed‐micro cracked phases is

ISSN:0044-2267    

DOI:10.1002/zamm.19970770711

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractIn this work a numerical and experimental study of nonlinear motion confinement phenomena in a nonlinear flexible assembly with vibro‐impacts is carried out. The assembly consists of two coupled cantilever beams whose motion is constrained by rigid barriers. In the theoretical model the impact nonlinearities are simulated by clearance nonlinearities with steep stiffness characteristics; special care is taken to model energy dissipation due to inelastic impacts. The theoretical results confirm that the vibro‐impact system possess motion confinement properties. Both transient and steady state motions are studied, and it is shown that under certain conditions the vibrational energy of the system is passively confined to only one of the two beams. These essentially nonlinear responses exist inspite of direct coupling between the two beams, and have no analogs in linear theory. The experimental results confirm the theoretical predictions both in the transient and steady state regimes. The passive nonlinear motion confinement phenomena reported in this and previous works can be utilized to enhance the controllability of flexible structures with symmetries, and to improve current shock and vibration isolation designs of such syst

ISSN:0044-2267    

DOI:10.1002/zamm.19970770712

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970770714

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe flow of a Bingham fluid in a concentric cylinder viscometer can be give rise to free boundary problems. In the region between the two rotating cylinders the fluid behaves like a viscous fluid if the shear stress, expressed as a linear function of the shear rate, exceeds a yield value, and like a rigid body otherwise. The surfaces dividing fluid and rigid zones are the free boundaries, where we assume that the shear rate is zero. Starting from a model proposed in a previous work, where just one fluid and one rigid zone were present, here we study the physical problem taking into account the possible formation of further rigid zones inside the fluid. We introduce a kind of “regularization” of the problem, pointing out the existence of a unilateral constraint to which the formation of new rigid zones is related. Each time the constraint comes into play, the problem must be reformulated by letting new free boundaries appear bounding the newly created rigid region. Moreover we analyse the possible collapsing of the rigid zo

ISSN:0044-2267    

DOI:10.1002/zamm.19970770715

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY