Influence of temperature on the vibration properties of tensegrity structures

Vibration health monitoring methods use the sensitivity of the natural frequencies to structural damage. Natural frequencies are sensitive to damage, but are also affected by environmental conditions like temperature changes. It is important to be able to distinguish between the effects of these different factors when using the vibration properties as a monitoring tool. This paper discusses the impact of damage and environment temperature changes on the natural frequencies of tensegrity ("tensile-integrity") structures, in particular noting that component bending is a prominent vibration mode, which motivates a use of non-linear beam elements with axial-bending coupling. The model considers not only thermal expansion effects, but also the change of the elastic modulus with temperature. Changes in natural frequencies produced by environment temperature changes are shown to be similar to the ones produced by damage. The geometry of tensegrity structures, the support conditions and the materials are found to be important factors. The sensitivity of the natural frequency to temperature changes is found to be dependent on pre-stress level. (C) 2015 Elsevier Ltd. All rights reserved.