The Research Of The Paris Formula Applied In Diagnosis Of The Structure Crack

The diagnosis of the crane metal structure fault is an important subject in the field of maintaining port securely producing. For the larger and larger crane, the accident about its metal structure sometimes takes place to give bad effects to safety produce and produce giant loss in economics and bad social influence. With the method of the diagnosis of fault, we can properly evaluate the state and predict the life-span of working metal structure and design the hardware and software system for application. We are absorbed in perfecting the system to make the system adapt to the practicality. The description study and perfect the theory of The diagnosis of the crane metal structure crack that its core is the formula of Paris on the FEM, APDL, UIDL and Visual Basic Program. The main content include:(1) Discussing the basis theory of fracture mechanics and advances of computation fracture mechanics that it is the branch of fracture mechanics. Expatiating the model of the crack growth life and its application.(2) Experimental Study on the method to get the stress of the structure without crack calculated by FEM to forecast the crack growth life is done if crack appears for the application of formula of Paris that it is the core of the diagnosis of the crane metal structure fault.(3) With the FEM-Ansys, the model of the specimen is established and the stress of model is compared with the stress is got through the Experiment; the stress intensity factor is compared with the formula of experience that verify the result of the calculation of FEM.(4) With Ansys secondary development technique, the value of the stress intensity factor is calculated with the crack growthing and is approximated as a curve. the variability the stress intensity factor can be got; To more accurately and more simply diagnose the crane metal structure fault ,the frame of the calculating the crack growth life and the crack grow thing variability is put forward according to the model of FEM through calculating the stress intensity factor of the random position at will with Ansys secondarydevelopment ;That is a new method of the diagnosis of the crane metal structure crack through the formula of Paris.(5) Perfecting the system of The diagnosis of the crane metal structure fault with Visual Basic program; For example, the standard profiled bar database and the calculating function of the geometric feature to non-standard profiled bar predigest the system use; If the technician want to diagnose the important part of the structure without the stress pattern of the model, the directing patterns how to measure the stress can work. The stress patterns of the M02 type crane have been calculated for Jitneying port, which enrich the database of the stress patterns.