This paper discusses the flow and fracture properties of high-strength armor steel PROTAC 500. Based on combination of both experimental and numerical studies, material parameters for the Johnson-Cook (JC) strength and fracture model were determined. For that purpose, experimental tensile tests were conducted at elevated temperatures (20/400 °C), various strain rates (0.001/1 s[sup]-1) and triaxialities of axisymmetric notched specimens (0.333/1.431). Some test specimens were photographed during the testing, and by means of image processing, input data for calculation of true stresses and strains up to the point of fracture were extracted. After determination of strength material parameters, tensile axisymmetric tests with different triaxialities were numerically simulated and triaxiality data from the simulations were taken for evaluation of the material parameters of the damage model. Validation study was also performed successfully. The results of this paper will enable numerical prediction of large deformation processes as well as possible fracture occurrence, its development and final size, for structures made of high strength armor steel, PROTAC 500.
COBISS.SI-ID: 13766939
The presented survey includes a comprehensive overview of mechanical failure mode causes for direct driven electric in-wheel motors. As electric vehicles evolve and develop, in-wheel motor driven vehicles gain acknowledgement, more and more papers are published in order to show individual design challenges and overcoming solutions for failure causes and effects. Obtainable literature is mainly concerned with integral electrical failure modes, neglecting structural causes and effects which in some cases interact. The presented paper inspects the most likely potential mechanical causes of failure modes for in-wheel motors and shows related paper%s results for comparison and reference. As several mechanical and electromagnetic layouts and construction topologies exist, only the most promising and generally used one has been studied within this work in order to emphasize sensible directions of further development. Failure mode and effects analysis (FMEA) has been made with severity rating which present mechanical failure potential for permanent magnet synchronous motors intended for in-wheel motor application.
COBISS.SI-ID: 13856283
In this study we analyzed CPR-related skeletal chest injuries (SCI) of 2148 patients who had undergone resuscitation for non-traumatic cardiac arrest, in the period 2004-2013. The percentage of patients injured and the number of SCI increased with age. Our study showed that rib and sternum fractures are much more frequent than generally considered. Increased compression rate and depth as well as changes in resuscitation guidelines contribute to the incidence and number of SCI. Human body injuries caused by mechanical load were analized, finding important rate, magnitude and age influence.
COBISS.SI-ID: 32159449
This work is focused on a parametric numerical study of the barrier\'s bar inclination shelter effect in crosswind scenario. The parametric study combines mesh morphing and design of experiments in automated manner. Radial Basis Functions (RBF) method is used for mesh morphing and Ansys Workbench is used as an automation platform. Wind barrier consists of five bars where each bar angle is parameterized. Design points are defined using the design of experiments (DOE) technique to accurately represent the entire design space. Three-dimensional RANS numerical simulation was utilized with commercial software Ansys Fluent 14.5. In addition to the numerical study, experimental measurement of the aerodynamic forces acting on a vehicle is performed in order to define the critical wind disturbance scenario. The wind barrier optimization method combines morphing, an advanced CFD solver, high performance computing, and process automaters. The goal is to present a parametric aerodynamic simulation methodology for the wind barrier shelter that integrates accuracy and an extended design space in an automated manner. In addition, goal driven optimization is conducted for the most influential parameters for the wind barrier shelter.
COBISS.SI-ID: 13859867
During the production of torsion bars, two different mechanical processes of inducing the residual stresses into the torsion bar are used: the presetting of the torsion bar and the deep rolling of the torsion bar. The process of presetting the torsion bar is carried out by twisting the torsion bar to the desired angle and releasing it to the new residual angle position. With controlled overstraining, favorable residual shear stresses are induced into the torsion bar, so the material is strain hardened and the yield point of the material is shifted and increased in the stress and strain space. The objective of the deep rolling process is to introduce compressive residual stresses into near-surface regions in order to increase the fatigue strength of the torsion bar. These two processes influence each other. The final level of residual stresses depends on the production sequence of these two processes and the production parameters of each process. The correct production sequence of these two operations and distribution of beneficial residual stress was simulated using the finite element (FE) method. To validate this model, the predicted surface residual stresses were compared by the X-ray diffraction (XRD) measurements of residual stresses.
COBISS.SI-ID: 13930523