Metal Structure Stress Monitoring Technology Research Combined With The Image Measurement And Finite Element Method

Metal structure is used widely in buildings, bridges, engineering machinery, shipbuilding and other fields. Its safety and reliability is directly related to the safety of human life. Stress real-time monitoring of metal structures can effectively evaluate the safety of the structure, and send warning information before structures failure.This paper attempts to establish a new approach:based on computer graphics measure and finite element method, through one or more camera to obtain displacement of characteristic points on structures, then input these dispalcement data to corresponding finite element model, as the initial displacement of the finite element model, then get stress clouds of the struture by calculating.The overall stiffness matrix accurately depicts the physical properties of the structure; the solution of the overall stiffness equation reflects the response of the structure under loads. Theoretical analysis found that:(1) node load and nodal displacements exist equivalent relation, which indicates that using nodal displacements instead the equivalent nodal forces will not affect the overall stiffness equation solution, and the nodal displacements can be measured by the image;(2) stress monitoring only need to measure the displacement of nodals which nodal force is not equal to0.Based on the technical route and theoretical analysis above, this paper uses VC++to call ANSYS software, through the image processing algorithm to acquire feature point deformation, and then input these deformation datas to ANSYS, like this, realize the method rapidly. This method has the following innovations:1) Realize non-contact stress monitor of structures, can be applied to some special occasions;2) Can obtain stress distribution cloud pictures of the integral structure, included internal stress informations (The strain resistance measurement only gets point stress on the surface of structure);3) Can consider the influence of gravity to structure;4) Results will not be influenced by temperature change; 5) Can measure the deformation of structures.This paper has done experiment for the monitor method. The experiment shows the monitoring method has higher precision and a certain degree of real-time under the experimental conditions. This paper involves parameterized model, software interface and image processing etc. In these areas, also gives some innovative realization processes, have some degree of reference significance.