Miroslav Španiel

Laser Powder Bed Fusion (LPBF) was used as a cost-effective, sustainable alternative to conventional subtractive methods. In this study, a finite element model was developed to investigate the effects of recoater geometry, recoating speed, and layer thickness on the mechanical performance of printed parts. The model incorporated a temperature-dependent elastic–plastic material law. Two blade types were were tested experimentally: a compliant rubber blade and a rigid ceramic blade. The experimental findings were used in the simulation as a print-failure criterion. The results validated the fixture-based measurements, demonstrating that the compliant blade did not impose significant mechanical stress on the printed part, even when the gap beneath the blade was fully closed. It was found that increasing the cooling time before depositing a new layer reduced the likelihood of build failure due to collisions between the sample and the recoater blade.

This paper describes and presents an experimental program of low-cycle fatigue tests of austenitic stainless steel 08Ch18N10T at room temperature. The low-cycle tests include uniaxial and torsional tests for various specimen geometries and for a vast range of strain amplitude. The experimental data was used to validate the proposed cyclic plasticity model for predicting the strain-range dependent behavior of austenitic steels. The proposed model uses a virtual back-stress variable corresponding to a cyclically stable material under strain control. This internal variable is defined by means of a memory surface introduced in the stress space. The linear isotropic hardening rule is also superposed. A modification is presented that enables the cyclic hardening response of 08Ch18N10T to be simulated correctly under torsional loading conditions. A comparison is made between the real experimental results and the numerical simulation results, demonstrating the robustness of the proposed cyclic plasticity model.

This paper details the numerical modeling of composite absorbers and an assessment of the influence of such deformation elements on a bus during frontal collision with a car. The absorber itself is designed as an assembly of thin-walled composite wound tubes oriented in the vehicle direction of travel. During the impact the tubes are crushed, causing energy absorption. Crash simulations were performed at various speeds using differing scenarios with the deformational member as well as without it. Comparative diagrams of force and velocity of the car and deformation of the bus structure were assessed