Research On The Tent Structure Based On Convex Four Bars Tensegrity

Tensegrity structure is a kind of special tension structure composed of compression bars and cables with the characteristic that the bars are only subjected to the axial pressure and the cables bear only tensile force.Tensegrity structure has gradually been applied in the field of industry,architecture and art,at present.It is still a new subject in the field of building tent.The design types are various based on the traits of tensegrity structure.In this paper,the research object is about the application of four bars convex tensegrity structure to design the tent.There are many kinds of four bars tensegrity structures used in the main structure of the tent.Several design schemes are initially determined by the structure deformation of the basic four bars tensegrity structure.Then mathematical modeling in MATLAB is necessary including building the nodes matrix of tensegrity structures firstly,deducting the components vector matrix though sorting the nodes matrix,then identifying the connection matrix of cables and bars based on the components connection relationship,and ultimately finishing the mathematical modeling of the structures.The force density method is applied in the stability analysis of the tent design programmes through the establishment of mathematical models and force equilibrium equation,which are completed under the condition of stable self-stress when the resultant external force is zero.The force density of the bars and cables are calculated by the equilibrium equation of force.What the positive result stands for that the component is under tension,on the contrary,the negative result stands for that the component is under compressive without the unstable plane structure.Once the all bars are under compressive and the all cables are under tension,the structure is stable,otherwise,the structure is unstable.The best program can be initially selected through the stability analysis.The internal space analysis of the four bars tensegrity structure selected initially.Defining the range of the four bars tensegrity structure is essential though deducing the formula of inscribed circle radius of four bars tensegrity structure,the space volume formula and the inclination angle formula of inner and outer membranes based on the mathematical modeling.On the premise of meeting the design requirements,the volume of the tent is optimized,and then the main structure of tent is identified.The minimum mass optimization analysis of the structure is necessary based on the force density method which is to calculate the internal force,in case of the wind load and snow load focused on the node of the tent.Based on the yield limit analysis of the solid cables and buckling limit analysis of the hollow bars,the minimum mass models of the tent and optimized calculation are established finally in MATLAB to achieve the minimum diameter of the cables and the inner diameter of the bars.In this paper,the cutting analysis of the outer membrane aims to get minimum enclosing rectangle area.Firstly 360-degrees circumscribed rectangle of single membrane is shaped,then reach an optimal result through the establishment of the external rectangular area formula.The minimum result is get depends on the whole rectangular shapes which there is a edge of rectangular coincided with a edge or two dots of the whole outer membrane is get.