The performance of Marciniak–Kuczinsky approach on prediction of plastic instability of metals subjected to complex loadings

The objective of the present paper is to analyse the performance of Marciniak-Kuczinsky (MK) theory on the prediction of formability of sheet metals subjected to complex loadings. Advanced constitutive equations taking into account isotropic and anisotropic hardening are applied to describe the material mechanical behaviour under linear and complex loadings. A comparative study on their accuracy on predicting the forming limits for the studied material is performed. Two deep-drawing quality sheet metals are selected. Several strain path changes are taken into account. A good agreement between the theoretical and experimental results was obtained. MK theory is an efficient and valuable tool on the prediction of plastic flow localization of sheet metals under complex loadings when proper constitutive equations are used.publishe

The formability prediction of twinning-induced plasticity steels

The proposal of this work is to predict and analyse the formability of twinning-induced plasticity steels through the Marciniak-Kuczinsky approach with emphasis on the solutions for improving the prediction results. The selected constitutive equations involve the Yld2000-2d plane stress yield function and the Swift strain-hardening power law. To understand the formability of the TWIP steel and the factors influencing it, a sensitive study on the effect of the mechanical properties of the TWIP steel on the Marciniak-Kuczinsky (MK) theory concept and the predicted forming limits is performed.publishe

Strain path changes in aluminum

Sheet metal forming processes involve large plastic deformation and changes in strain path. In this work, a detailed analysis of a commercially pure aluminum sheet subjected to tension-tension sequences with pre-strain in the rolling direction (RD) and reloads along different directions is presented, taking into consideration the mechanical behavior and texture evolution. Two main hardening behavior tendencies are observed, depending whether the reloading direction occurs for an angle smaller or larger than 45º.publishe

Measuring the stability of fundamental constants with a network of clocks

The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models

Measuring the stability of fundamental constants with a network of clocks

The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models