Instantaneous Stress Field Identification For Steel Bracket Of Roof Latticed Truss Structure In ShenZhen Citizen Center

In the past, space latticed truss structure was treated as a exceptional and non-traditional structure, but now is accepted as an economical and popular structure. In the one hand, there are many advantages in SLTS such as high space stiffness, moderate stability, good Earthquake resistance capacity, sound bearing capacity. In the other hand, due to magnitude dimension, subjected to random load ,and exposing in bad environment ,SLTS are affected easily by the natural disaster. Structure intelligent health monitor is a method using spot and non-damage equipment, getting structure internal information and analyzing all kinds characters of structure respo nse, then acquiring the structures change due to damage and degeneration. How to monitor and diagnose the capability of a structure and predict the damage before the disaster is become a research issue now.The intelligent inspect system for roof SLTS in Shenzhen citizen center is selected as a practice engineering background in this paper, the structure is a new political and cultural center and a symbolic architecture in ShenZhen which overall structural area is 2.1 million square meter, the roof is the largest space lattice in the world which is 486 meter long and 154 meter wide. In the paper, we discuss a part of the healthy monitor system, including instantaneous stress filed identification for bracket, stress anlysis of welding line and key point; alarm of key point stress condition. Fuzzy pattern recognition method and FEA method are adopted in the dissertation.The safety of steel bracket has close relationship with overall structure. In the paper, firstly, the fuzzy pattern recognition theory is introduced,structure intelligent healthy monitoring based on the fuzzy pattern recognition is analyzed in detail. In order to validate the feasibility of fuzzy pattern recognition applied to the stress fieldinstantaneous recognition and the accuracy of data-collection system, we design the bracket model and did a model experiment to prove the accuracy of data-collection system and the feasibility of fuzzy pattern recognition theory using data-collection system, then, we discuss the influencing factor in the selection of key point. Finally,the intelligent monitoring method is introduced including the instantaneous stress field identification of bracket and the selection of key points, the evaluation and alarm according to key points work state ,etc.In the paper, the FEA model is constructed using the large software ANSYS,the element adopt shell63 element. Through the static analysis of the important six brackets, we learned the distribution of stress and strain to some extent. Then we know the key area of the bracket, get many stress field modes and saved.After the instantaneous stress field identification of Steel bracket.we estimate the stress value. If the amount is larger than the limit, the monitor system can alarm at once.At the same time,any time stress condition of bracket can show on the computer screen that convenient the workers inspect the safety of structure.