Numerical simulations have become essential in engineering and manufacturing processes involving plasticity. The reliability and effectiveness of the simulations depend strongly on the accuracy of the adopted constitutive model. Accordingly, in recent years, an increasing interest is pointed towards experimental procedures and characterization methods that can be used to identify the constitutive parameters of advanced plasticity models, which allow to simulate properly the plastic behaviour of complex materials like, for instance, high strength steel. This paper provides a thorough review of the current stateof-the-art, looking at both academia and industry. The available methodologies can be subdivided in two main areas: quasi-homogeneous material tests with analytical or numerical post-treatment of the experimental data and heterogeneous tests coupled with inverse methods for parameter identification. For each method, a brief description and references to norms and articles is provided, illustrating the advantages and the disadvantages.

The main advantage of 3D printing is manufacturing complex and innovative shapes which guarantee high mechanical properties. Therefore, it is necessary easily figure out the most suitable structure for the required design requirements. The well-known strategy to design sandwich panels is evaluating collapse maps as they determine the panel performances based on their geometrical features. The aim of this study is to update the traditional collapse maps by showing how the core shape can improve the sandwich beam performance. The collapse maps proposed are based on advanced analytical models than the traditional Gibson theories. The analytical modelling of the indentation phenomenon is based on Vlasov’s model. The analytical modelling of the bending phenomenon is based on the First Shear Order Theory. The overall panel stress and strain maps are computed superposing both effects. A composite sandwich panels with Gyroid core based are analyzed to verify the proposed model consistency. A core failure criterion is chosen by experimental testing evidence on the representative core structure. Once the computed stress state overtakes failure criterion ones, the critical load is defined. In the end, the model is exploited to compare the performances of four sandwich panels with cores based on different lattice structures.

The metal additive manufacturing (AM) is a technology that is rapidly spreading in the industrial sector with its enormous potential in making components with complex shapes and low weight, ensuring a high structural strength.However, the mechanical properties of the components depend on the printing process, and the interactions between the process variables and the final material behaviour is still not totally understood. In this work, 12 different types of tensile specimen were built by AM using the laser powder bed fusion (L-PBF) technique; the used material is the 316L stainless steel. The specimens have the same geometry and the same process parameters in terms of layer thickness, hatch space, laser power, spot diameter, scanning speed and platform preheating temperature, while different laser scan strategies and building orientations are evaluated. The scope is to characterize the plastic behaviour of such specimens and study the differences due to distinct printing strategies.Stereo digital image correlation (stereo-DIC) was used to evaluate the deformation state and analyse the material anisotropy. Finally, the microstructure and presence of defects were investigated through the optical microscopy (OM) and the scanning electron microscopy (SEM). The analysis shows how the plastic behaviour and the formation of defects are remarkably influenced by the laser scan strategy and by the building orientation.

In this paper, the possibility of characterizing the thermomechanical behavior of metals using the virtual fields method (VFM) and suitable specimens with heterogeneous strain and temperature fields was demonstrated using simulated experiments. The used geometry is a double-notched tensile test with a Gaussian distribution of temperature over the surface. The chosen constitutive model is the Johnson-Cook hardening law coupled with the Hill48 anisotropic yield criterion. First the VFM strategy and the simulated experiments are described. Then the results are presented showing three case studies, (i) only the effect of the temperature is identified, (ii) the whole set of constitutive parameters is identified at the same time, (iii) a two-step identification is performed. The potentiality of the method as well as the main problems are discussed extensively.