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Variational Methods for Nonsmooth Mechanics


Fetecau, Razvan Constantin (2003) Variational Methods for Nonsmooth Mechanics. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/VXBJ-R447.


In this thesis we investigate nonsmooth classical and continuum mechanics and its discretizations by means of variational numerical and geometric methods.

The theory of smooth Lagrangian mechanics is extended to a nonsmooth context appropriate for collisions and it is shown in what sense the system is symplectic and satisfies a Noether-style momentum conservation theorem.

Next, we develop the foundations of a multisymplectic treatment of nonsmooth classical and continuum mechanics. This work may be regarded as a PDE generalization of the previous formulation of a variational approach to collision problems. The multisymplectic formulation includes a wide collection of nonsmooth dynamical models such as rigid-body collisions, material interfaces, elastic collisions, fluid-solid interactions and lays the groundwork for a treatment of shocks.

Discretizations of this nonsmooth mechanics are developed by using the methodology of variational discrete mechanics. This leads to variational integrators which are symplectic-momentum preserving and are consistent with the jump conditions given in the continuous theory. Specific examples of these methods are tested numerically and the longtime stable energy behavior typical of variational methods is demonstrated.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:discrete mechanics; multisymplectic geometry; rigid-body collisions; symplectic integrators
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Applied And Computational Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Marsden, Jerrold E. (advisor)
  • Hou, Thomas Y. (co-advisor)
Thesis Committee:
  • Marsden, Jerrold E. (chair)
  • Cohen, Donald S.
  • Pierce, Niles A.
  • Hou, Thomas Y.
Defense Date:14 May 2003
Non-Caltech Author Email:van (AT)
Record Number:CaltechETD:etd-05222003-110241
Persistent URL:
Fetecau, Razvan Constantin0000-0001-9059-0283
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1934
Deposited By: Imported from ETD-db
Deposited On:22 May 2003
Last Modified:03 May 2021 21:48

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