Form-finding Optimization Analysis And Structure Performance Research Of Tree Structures

Tree structures have clear load transfer, reasonable bearing and beautifulappearance. It is a kind of biomimetic structures that integrates morphological bionicsand structural bionics as one. It can be used in some structure projects such as largeplaygrounds, cultural venues, airports and station platform. With the continuousapplication and deep research of tree structures, there are some issues in analysistheory need to improve, such as the simple and efficient form-finding methods of treestructures, and the impact of non-uniform temperature field on tree structures undersolar radiation. The questions mentioned above is researched deeply by combining themethods of numerical simulation, experimental studies and site measurement, andobtains some research results, in order to provide some reference on the theoreticalresearch and engineering applications of tree structures.As a kind of biomimetic structures, the basic concepts of tree structures such asdefinition and composition coding is not clearly specified. Tree structures are definedthat a kind of structure with certain supporting function, which are designed on thebasis of researching the shape and stress characteristics of trees in nature. In order tofacilitate analysis and improve basic concepts of tree structures, the structurecomposition of tree structures and specifies the coding of tree structures are proposed.On the basis of summing up practical engineering applications, tree structures areclassified according different classification methods.The morphology of tree structures concern the mechanical properties of structure.It is worthy of attention and study how to make the structural force more reasonable.On the basis of comparing the physical and numerical simulation form-findingmethods of tree structures, and researching the sliding cable element, an efficientform-finding method of tree structures is proposed based on sliding cable element,which simulates the pulling only characteristics of the cable element and operateseasily. This method can reduce element bending moments of tree structures undernode and uniform load effectively, by applying to the form-finding research of2D treestructures, and the effect is ideal. Taking two-level branching and three-levelbranching tree structures as example, common steps of static and dynamicform-finding methods are summed up. Through simulation experiments and comparedwith numerical form-finding method, the feasibility of this method based on slidingcable element is verified. Two-level branching tree structures under node load are optimized and the optimal shapes of tree structures are researched preliminarily.The element bending moments after form-finding will reduce, by applying theform-finding method based on sliding cable element of3D tree structures, and theoptimization will be summed up. A comparative analysis of structural mechanicsproperties is carried on the tree structures shape after form-finding and the actualshape, by applying this form-finding method to the tree structures analysis ofTianshan Sea World Rice Cube project. Through structure performance analysis of theoverall structure with different branch level, the overall structure mechanicalproperties supporting by two-level branching tree structures is better than one-levelbranching tree structures, and much better than ordinary column structure. Thehinged connections or rigid connections between the tree structures and the roof haslittle effect on the overall performance of the structure. The joint form of treestructures has a great effect on the composite structure of single tree structures androof. Considering that the ring beam of Rice Cube is on the ground, the joint form oftree structures has little effect on the overall structure performance.In the action of large indoor space environment heating or cooling, external solarradiation and large temperature difference between inside and outside, the overallstructure supporting by tree structures is under the action of dynamic non-uniformtemperature field. By observing and collecting data of the structure temperature ofRice Cube project in summer on site, verifying the non-uniform temperature fieldnumerical simulation result from theoretical analysis, researching the effect on thestructure performance of tree structures supporting under different temperatureoperating conditions, temperature action has a greater impact on the structure,non-uniform temperature field under Solar radiation has a greater impact on theoverall structure. Consider the constant temperature of the indoor swimming part inRice Cube, tree structures analysis under non-uniform temperature field is morerealistic. Compared with ordinary column structure, the overall structure supportingby tree structures can reduce the element stress and node displacement effectivelyunder temperature action.Based on the performance research of3D tree structures, forest structures systemwhich can improve the lateral resistance and make structure force synergistically isproposed, and the structure performance research of this system is carried on.