No abstract

In the near future, mega-long-span structures will be required for creating stable microclimate over large areas, regardless of the natural conditions, for comfortable living of people. Thin-walled shell structures made of carbon materials with high strength properties are best suited for this purpose. The problem with thin-walled shells resides in vibrations caused by the action of external forces, which can lead to structural failure. The paper presents and experimental study of influence of the multilayer nature of reinforcement of open thin-walled cylindrical carbon shells on their natural vibrations. Experimental data have been compared to the theoretical calculations of open thin-walled cylindrical shell vibrations taking into account the frequency spectrum splitting. It has been found that with the increase in the number of carbon fabric reinforcement layers, vibration frequency deviation in open thin-walled cylindrical carbon shells increases at the initial stage as compared to the analytic model.

Nowadays, open cylindrical shells are widely used in structures in construction, aviation, energy, oil, and other industries. Shell structures are exposed to short-term cyclical influences in the course of operation; these influences cause forced vibrations of the structure which trigger the internal dynamic mechanisms, changing the natural vibrations of the structure, which has a significant impact on the strength characteristics of the shell. Carbon-fiber-reinforced plastics (CFRP) are used as an effective material for such structures. This is a durable and lightweight material. Due to its high cost, its application used to be efficient only in aircraft and in the space industry. Improvement of manufacturing techniques has made it possible to expand the range of CFRP applications. Due to their thinness, CFRP products are prone to vibrations. Vibrations can cause resonance condition, which can result in structural collapse.