A CDM (continuum damage mechanics) model for damage evaluation is here considered and applied to the study of two different typologies of notched and cylindrical specimens. The model presents some parameter and authors determined them in a previous work testing cylindrical and smooth specimens. Firstly fatigue characterization was conducted and the SN curves found. In order to evaluate the capability of CDM model to predict the sequence effect and to simulate a more realistic loading condition, tests with various loading blocks were carried on and in particular high-low, low-high and random blocks were applied to the three specimens considered. Model previsions showed good agreement with results for each geometry considered. Keywords: Continuum damage mechanics; variable amplitude fatigue; load sequence effect. Nomenclature D damage variable n i number of cycles at a given stress amplitude N i number of cycles to failure at a given stress amplitude max maximum stress m mean stress a stress amplitude, a = max -m M 0 , coefficients of the damage model ( ) function in the damage model H, a coefficients of function ( ) defined as x = 0 if x < 0, x = x if x > 0
In this paper the possibility to employ the Digital Image Correlation (DIC) technique for the mechanical behaviour analysis of metallic foam was investigated. Image Correlation allowed to measure displacement and strain fields on closed and open cells aluminium foam specimens under two different loading conditions (compression and shear) and to characterise, with opportune calculation, information on the mechanical behaviour of foams. The adopted technique is suitable to conduct a deep analysis and also to appreciate the local heterogeneities that appear in a specimen during test. The parameters obtained with DIC analysis are confirmed by the global data obtained by testing machine proving the adopted methodology represents a valid tool for the study of these new materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.