Experimental Analysis of Shell-like Deployable Anchors for Increased Tensile Resistance

Structures with deployable and compliant mechanisms are new to the domain of underground geotechnical systems. An anchor with rotationally deploying compliant thin-wall elements has been developed. This paper presents variations of this anchor that are targeted to increase the surface area associated with the anchor. This increased surface area correlates to higher skin friction to better resist tensile forces. The number and sizing of the deployable components, called awns, are investigated. The work presented here includes methods to change the deployment behavior of the awns by changing the shape of the awns and by using functionally graded materials for increased resistance when the anchor is subjected to uplift forces. Test members were fabricated from a combination of flexible and rigid polymers via additive manufacturing. Experimental testing included anchor deployment tests and awn tension tests. For deployment tests, torque was applied to an anchor placed in clear sand. Awn tension tests provided additional information about the deformation of functionally graded awns through isolated testing of the awns. The presented design and experimental methodologies give insights into the behavior of small-scale deployable anchors.