DISPLACEMENT OF
THE NEUTRAL AXIS BY BENDING OF A BIMODAL VISCOUS BEAM
K.Hadjov, D.Dontchev
IDENTIFICATION OF PARAMETERS OF THE PHENOMENOLOGICAL
FAILURE CRITERIA
K. Hadjov
DISPLACEMENT OF THE
NEUTRAL AXIS BY BENDING OF A BIMODAL VISCOUS BEAM
K.Hadjov, D.Dontchev
University of
Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: klm@uctm.edu |
Received 13 February
2002
Accepted 26 February 2002 |
This work is intended to determine the neutral
axis displacement by bending of beams which possess different viscoelastic
behaviors by traction and contraction. Similar effects are well known in the
elastic case. Introducing different Hooke's laws and equalizing the normal
forces in the tracked and contracted section we resolve the above-mentioned
problem in the elastic case. We use the hereditary theory of Boltzmann-Volterra
and some operator relations to obtain the viscoelastic solution. Thus, the
neutral axis displacement is obtained as a time dependent function. The elastic
solution is obtained as a particular case. Examples concerning different section
shapes are resolved.
Keywords: bimodal beam, viscosity, neutral axis.
IDENTIFICATION
OF PARAMETERS OF THE PHENOMENOLOGICAL FAILURE CRITERIA
K. Hadjov
University of
Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: klm@uctm.edu |
Received 25 April
2002
Accepted 3 May 2002 |
In this work we investigate a failure criterion
for isotropic homogeneous solids containing the three invariants of the stress
tensor. There are two aims of the paper. The first one is to determine the
limits of variation of the failure criterion parameters related to the failure
curve closure conditions, using elementary failure experiments. The second
aim is to determine the influence of the third stress tensor invariant on
the limit (failure) curve shape. A theoretical curve concerning brittle rupture
in the deviator plane was compared with experimental results to confirm the
necessity to include the third stress tensor invariant in the failure criterion.
Keywords: failure criteria, stress tensor invariants
