Holonomic constraints : an analytical result

Systems subjected to holonomic constraints follow quite complicated dynamics that could not be described easily with Hamiltonian or Lagrangian dynamics. The influence of holonomic constraints in equations of motions is taken into account by using Lagrange multipliers. Finding the value of the Lagrange multipliers allows to compute the forces induced by the constraints and therefore, to integrate the equations of motions of the system. Computing analytically the Lagrange multipliers for a constrained system may be a difficult task that is depending on the complexity of systems. For complex systems, it is most of the time impossible to achieve. In computer simulations, some algorithms using iterative procedures estimate numerically Lagrange multipliers or constraint forces by correcting the unconstrained trajectory. In this work, we provide an analytical computation of the Lagrange multipliers for a set of linear holonomic constraints with an arbitrary number of bonds of constant length. In the appendix of the paper, one would find explicit formulas for Lagrange multipliers for systems having 1, 2, 3, 4 and 5 bonds of constant length, linearly connected.Comment: 13 pages, no figures. To appear in J. Phys. A : Math. The

Order reduction, projectability and constrainsts of second-order field theories and higuer-order mechanics

The consequences of the projectability of Poincar\'e-Cartan forms in a third-order jet bundle $J^3\pi$ to a lower-order jet bundle are analyzed using the constraint algorithm for the Euler-Lagrange equations in $J^3\pi$. The results are applied to the Hilbert Lagrangian for the Einstein equations. Furthermore, the case of higher-order mechanics is also studied as a particular situation.Peer ReviewedPostprint (author's final draft

Eksternal dari fungsional

Dalam Tulisan ini dibicarakan tentan ekstremal dan funasional T Cy(x)3 yaitu syarat periu dan cukup untuk fungsional 1 [ y(x) J ekstremal, multiplikator Lagrange dan sya:rat transversal. Juga dibahas transformasi Bolza, Mayer dan La,s4ranv,P, serta bentuk benda solid dengan.gaya penghambat (dra,s,,

Confirmation of Lagrange Hypothesis for Twisted Elastic Rod

The history of structural optimization as an exact science begins possibly with the celebrated Lagrange problem: to find a curve which by its revolution about an axis in its plane determines the rod of greatest efficiency. The Lagrange hypothesis, that the optimal rod possesses the constant cross-section was abandoned for Euler buckling problem. In this Article the Lagrange hypothesis is proved to be valid for Greenhill's problem of torque buckling. The corresponding isoperimetric inequality is affirmed.Comment: 4 page

Reexamination of the A-J effect

We establish four necessary and sufficient conditions for the existence of the Averch-Johnson effect in a generalized version of their famous model of the rate-of-return regulated firm. The four necessary and sufficient conditions are then compared to the two stronger sufficient conditions for the Averch-Johnson effect found in the literature. Our analysis also permits us to put to rest a somewhat protracted debate about the very existence of the Averch-Johnson effect.