STABILITY LOSS OF TAPE-SPRINGS UNDER COMPRESSIVE LOADS: A FINITE ELEMENT ANALYSIS

Tape springs are thin, cylindrical shells that have versatile usage, ranging from simple measuring tapes, through clockwork springs, up to space antennas, hinges and self-deploying structures. They provide easy and compact storage, yet they can be extended to be used as beam-like load bearing elements. Under opposite-sense bending load they can easily lose their stability in a snap through phenomenon. Although the same-sense bending theoretically also results in a snap-through, experience shows that this cannot be realized as a torsional buckling mode emerges earlier. The usual applications make use either of their storability, the snap-through phenomenon, or the propagating moment, as it provides a practically constant, curvature-independent bending characteristic. Although they can be used as load bearing construction elements, their stability under compressive loads (their buckling behavior) was not analyzed. To plan measurements later, it was necessary to perform preliminary investigations to examine the expected behavior of these shell types.