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Approximation and optimization of curved mechanical structures

Collaborator: J. Sprekels, D. Tiba, R. Vodák

Cooperation with: V. Arnautu (``Alexandru Ioan Cuza'' University, Iasi, Romania)

Supported by: DFG-Forschungszentrum ``Mathematik für Schlüsseltechnologien'' (Research Center ``Mathematics for Key Technologies''), project C8

Description: The work for this research project continued in several directions. We have finished paper [1] concerning the optimization of structures like curved rods and shells. This gives a rather complete theoretical treatment of the subject, under low regularity assumptions for the geometry. Numerical experiments involving three-dimensional curved rods are also included. Notice that in [3] the case of planar arches was completely solved. Paper [5] introduces a new approach, based on control theory, for the general linear elasticity system and discusses some thickness optimization problems for plates. In [2] stable approximation methods are investigated in connection with the curved rod model proposed in [4]. It is well known that differential equations involving very small parameters (in this case the ``thickness'' of the rod, i.e. the area of the cross section) may be very difficult to handle via standard finite element methods. This difficulty is known under the name ``locking problem''. We propose a method that can improve the stability properties in computations related to curved rods.

Finally, paper [6] considers a new way to obtain a model for the deformation of elastic curved rods, of asymptotic type. The new estimates that we derive allow to study curved rods with piecewise  C1  parametrization.

References:

  1. V. ARNAUTU, J. SPREKELS, D. TIBA, Optimization problems for curved mechanical structures, WIAS Preprint no. 812, 2003, submitted.
  2.          , A stable approximation method for curved rods, in preparation.
  3. A. IGNAT, J. SPREKELS, D. TIBA, Analysis and optimization of nonsmooth arches, SIAM J. Control Optimization, 40 (2001/2002), pp. 1107-1133.
  4.          , A model of a general elastic curved rod, Math. Methods Appl. Sci., 25 (2002), pp. 835-854.
  5. J. SPREKELS, D. TIBA, Optimal design of mechanical structures, WIAS Preprint no. 863, 2003 .
  6. D. TIBA, R. VODÁK, A general asymptotic model for piecewise  C1  curved rods, in preparation.



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2004-08-13