The Research Of The Failure Mechanism And Fracture Mode For Several Metals

The accident of fracture is one of the main factors for invalidation of engineering component. It is the main task for solid mechanics operators to research and analyse the fracture factors and fracture mode as well as how to avoid fracture or decelerate fracture and so on.The predecessor have made a mass of work, some work is to gain the empirical formula for judging material fracture by large numbers of experiment; Some work is researching the theory of fracture based on basic assumption in solid mechanics.But, because of the different character between different material and the complicacy of the stress aspect by structure or component and so on, it is unable to explain the fracture of the material in sundry aspect by uniform theory.It takes two metals what were wide used in application as the research objects, the metals are steel and duralumin, the two aspects of work are mostly done like this :(1)Experiment analysis. Do the failure experiment of the material, used the electron microscope to scan the fracture of the two metals in order to gain the SEM pictures, analyze the fracture mode and failure mechanism by observing the SEM pictures,(2)Theory analysis. Based on the empirical formula, analyze the advantage and the weakness of the Empirical formula; gain one function by analyzing the theory like f (σ₁,σ₂,σ₃), analyze and judge whether it is effective and reasonable, the relation is gained between the function and the factor by make use of another stress function which also like f (σ₁,σ₂,σ₃), the function between them can be found, and use the function into the Empirical formula, rewrite the Empirical formula, analyze and judge whether it is effective and reasonable by compare the two Empirical formula.The experiment analysis main to observe and research the fracture mode and the corresponding mechanics mechanism, the theory analysis can give the different conditions of different fracture mode by theory criterion, the setup can be done by the conditions, and so the fracture can be avoid or accelerate the fracture.