Poisson’s ratio is one of the fundamental characteristics in the material models that are used. In engineering practice, its values are assumed to be constant in the elastic and in the plastic region. In this paper, the conventionally used values of this number for steel materials and aluminum alloys are confronted with experimental results. By using non-contact strain measurements with the DIC (digital image correlation) method, the evolution of the Poisson ratio value in the regions of transition from the elastic to the plastic region as well as in the regions of large plastic deformations was documented. The obtained experimental results are graphically compared using the proposed strain scaling. The gradient of the Poisson ratio changes in the vicinity of the yield stress is significant, indicating the need for a refinement of the material models in this region. Deviations from the conventionally used value of this number were found in the large plastic deformation region. In conclusion, a possible approach for improving the accuracy of simulations in FEM softwares was formulated.

Additive metals are practically identical in strength to the properties of conventionally produced materials. This article experimentally analyses strength properties and fatigue properties in the tensile–pressure mode for two different directions of 3D printing of AlSi₁₀Mg material. The resulting fatigue parameters of the Basquin curve are confronted with a conventionally produced alloy of the same composition. The microstructure analysis explains the different fatigue properties obtained by these two material production technologies. Phenomena such as strength enhancement in additive manufacturing material, anisotropy of cyclic properties, and cyclic hardening are discussed. The limits of current additive manufacturing are clarified, and the future direction of research in this field is outlined.

The development of additive manufactured metals is in the transition phase, from research into the technology of 3D printing and the resulting properties of the metals towards their use in industrial practice. The article analyses the possibilities of producing bicycle frames using 3D printing. The stresses in a bicycle frame are analysed for the measured load spectra and FEM simulation. The approach to the fatigue life assessment of the bicycle frame is based on directly measured load multipliers and detailed FEM simulation with the subsequent calculation of fatigue damage in the individual planes of the critical point of the frame respecting the multiaxial stress state. The scatter of the cyclic properties of the AM material is considered by a statistical approach. The operational fatigue lifetimes of a frame made by 3D printing and one of conventional technology are compared.

Purpose: In recent years, there has been increasing interest in the measurement of material properties under specific conditions, such as the measurement of microspecimens. The analysis of materials with specific properties concentrated in a small volume is becoming increasingly important. Manufacturing and measurement of microsamples are complex and often require specialized equipment. Therefore, the paper aims to propose a solution to the problem of microspecimens using notched specimens and inverse identification of constitutive parameters. Design/methodology/approach: First, calibration measurements were made with notched specimens from S355 steel. Afterward, the discussed welded joint was first investigated by the uniform stress method. Consequently, several notched specimens were manufactured from different areas of the weld. The full strain field was measured using the digital image correlation (DIC) method. Subsequently, the constitutive parameters of the material between the notches were inversely identified. Findings: The proposed approach of inverse identification of constitutive parameters by using notched specimens and full-field strain measurements appears to be a suitable method for evaluating the properties of materials that are concentrated in a small volume. The proposed approach is easy to use and straightforward. The strain data used for the identification are only from a line in the narrowest cross-section. Originality/value: The paper presents the use of DIC with notched specimens to investigate the constitutive parameters and conventional material properties of a material concentrated in a small volume without the need to use microspecimens. Hence, unlike other inverse identification methods that use a 2D strain field, the proposed method uses only a 1D strain field. Thus, the used strain field lies only in the identified material.