Textile Strain Gauge for Inflatable Structures Project

One of the important elements of an inflatable structure is the restraint layer, made of textile straps that are woven together. This provides the structural support for the article and reacts with the internal pressure load. For this layer to maintain its strength, stiffness and safety margins under pressure, it is critical for designers and analysts to understand how the load varies within each strap. Current technology only permits the strap load to be measured by using a strain gauge attached to a metal clevis that connects the strap to the bulkhead on either end. The loading throughout the strap, however, is not linear and varies throughout the strap's length. Because the strain gauges have to be installed on metal at one location, they are unable to measure load variation within the straps. The proposal is to develop a textile strain gauge that can be used at various locations on the straps to measure strain as the straps are loaded. The project was completed via a multi-division collaboration within JSC and university partnerships. A number of device concepts were developed and tested that utilize a conductive material directly embedded/adhered to the restraint layer strap. The material has a natural electrical resistance, and as it is stretched (along with the strap) the resistance in the device will change. This resistance change can be monitored and correlated to a change in the strap load. More »