Abstract
Abstract The paper deals with the effect of stress state on the dynamic damage behavior of ductile materials. The rate- and temperature-dependent continuum damage model has been enhanced to take into account the influence of the stress triaxiality and the Lode parameter on damage condition and on rate equations of damage strains. Different branches of these criteria depending on the current stress state are considered based on different damage and failure processes on the micro-level. To get more insight in the dynamic damage and fracture processes micro-mechanical behavior of void-containing representative volume elements have been analyzed numerically. These three-dimensional numerical simulations based on different dynamic loading conditions take into account a wide range of stress states in tension, shear and compression domains. Based on the numerical results general trends of dynamic damage and failure behavior can be shown and stress-state-dependent equations for damage criteria and for the formation of damage strains can be proposed.
Highlights
During the last decades the use of high quality ductile metals like high strength steels, advanced high strength steels and various improved aluminum alloys in complex engineering structures has been remarkably increased especially caused by demands on economic, environmental and material strength requirements
Constitutive approaches taking into account large strains, high strain rates and thermal softening as well as stress-state-dependent damage and fracture criteria have to be developed to realistically predict the failure mechanisms observed in experiments and in various engineering applications
The anisotropic continuum damage model proposed by Brünig (2003,2004, 2006); Brünig and Gerke (2011) is used to predict the rate-dependent inelastic deformation behavior as well as the evolution of ductile damage and failure in aluminum alloys caused by dynamic loading
Summary
During the last decades the use of high quality ductile metals like high strength steels, advanced high strength steels and various improved aluminum alloys in complex engineering structures has been remarkably increased especially caused by demands on economic, environmental and material strength requirements. Detailed information on stress state dependence of the microscopic mechanisms can be obtained by systematic finite element analyses with micro-defect containing unit-cells loaded by different macroscopic stress states (Barsoum and Faleskog (2011); Brünig et al (2013, 2014, 2018b); Gao and Kim (2006); Gao et al (2005, 2010); Kim et al (2003); Nielsen et al (2012); Scheyvaerts et al (2011); Zhang et al (2001)) Their quasi-static numerical studies have shown that the stress state remarkably affects the macroscopic deformation of the representative volume elements, the growth of the micro-defects and the amount of the fracture strain. The stress-state-dependent continuum damage model proposed by Brünig et al (2013, 2018b) will be reconsidered and modified in the present paper and assessed to ensure its suitability for dynamic problems
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