  In this work we present the general phase behavior of short tubelike flexible
polymers. The geometric thickness constraint is implemented through the concept
of the global radius of curvature. We use sophisticated Monte Carlo sampling
methods to simulate small bead-stick polymer models with Lennard-Jones
interaction among non-bonded monomers. We analyze energetic fluctuations and
structural quantities to classify conformational pseudophases. We find that the
tube thickness influences the thermodynamic behavior of simple tubelike
polymers significantly, i.e., for given temperature, the formation of secondary
structures strongly depends on the tube thickness.
