Modelling of 25m Diameter Air Inflated Flexible Structure 2009-01-3168
A requirement of low cost, pollution free, flexible shelter was required for storing and housing costly equipment in remote areas. As such, a concept of an inflatable structure was thought of. This inflatable flexible structure is a mobile system, which could be used for housing costly equipment for providing emergency services, or used as transit camp at remote places.
The flexible dome would be required to be inflated with air blowers for 4 to 5 hrs initially. These air blowers would be required to be operated continuously, for maintaining a constant pressure of about 4 mbar inside the envelope. Further it is provided with air conditioning units for controlling the temperature and humidity inside the envelope.
The hemispherical structure is fabricated from coated fabrics having resistance to environmental degradation. It is also designed to withstand external wind speed up to 100 kmph. The modeling of the hemispherical envelope is carried out for the low cost inflatable structure, which has potential use as a mobile system.
The inflated structure is grouted at the circular periphery for minimum leakage of air. The hemispherical structure has a rectangular passage for the entry of personnel. It is reinforced with other rectangular openings for the interfacing of the air blowers and the air conditioning ducts. There are two layers of coated fabrics in hemispherical configuration. The intermediate space between the fabric layers is utilized as air cushion.
The Finite Element (FE) modeling is carried out for analyzing non-linear materials used in the hemispherical structure for providing a good approximation with the practical results. The FE modeling analysis shows the limit loads that the flexible hemispherical structure could withstand against high winds. It could also depict the behavioral pattern of the structure as a whole, when it is subjected to uniform or vibrant wind loadings. Care has to be taken in selecting the proper materials for fabrication, as the system could be required for operation in emergency and under harsh environmental conditions.