investigating the feasibility of a proposed model for geometric design of deployable arch structures

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are sles. these polygons, in turn, are linked into appropriate arrangements constituting deployable structures, which are either flat or curved in their final deployed configuration. these structures are deployed and demonstrate a huge volume expansion, and this process can be reserved. from a structural point of view, deployable structures have to be designed for two completely different loading conditions, under service loads in the deployed configuration, and during deployment. from a geometric point of view, the whole idea behind this type of deployable structures is based on the sles. because of their numerous advantages, deployable structures have been investigated, designed and constructed by many engineers both for earth and space applications. in the present study the feasibility of a proposed model for geometric design of deployable arch structures has been investigated by abaqus software. the deployable arch presented throughout this work is bi-stable in the sense of being self-standing and stress-free when fully closed or fully deployed, but they represent a high nonlinear geometric behavior during deployment process. the nonlinear behavior of such structures is considered as snap-through behavior. the snap-through phenomenon plays a fundamental role in the efficiency of deployable scissor-type structures; otherwise the structure loses its workability. providing deployability conditions leads to more designing expenses in contrast with ordinary undeployable structures. the additional expenses might be due to sophisticated designing of kinematic connections to guarantee the required deployability. therefore a parametric investigation of the behavior of stated structures under deployment is necessary in order to minimize internal forces. the results indicate that the geometric design methodology for deployable arches of arbitrary curvature, accounting also for the discrete joint size, has been applied successfully for the geometric design of a semi-elliptical arch. verification of deployability has been achieved by deployment simulation with the finite element method. a preliminary structural design indicates the overall feasibility of such an arch with a span of 13.6 m, subjected to dead, snow and wind loads.