Material’s Strength Analysis of the Coupling Node of Axle of the Truck Trailer

Road transport plays an important role in the transport of goods and people and is important for the national economy. Damage usually excludes the means of transport from operation, which causes disruption of supply chains. One such damage is the failure of the suspension system of the vehicle or trailer, which usually occurs when the vehicle is heavily loaded. Such a defective system has been analyzed in this publication. Mathematical apparatus and finite element method (FEM) numerical simulations were used. A dangerous axle cross-section in terms of load was indicated and the maximum stresses in this area were calculated for two types of roads. On highways, the stress at the critical point was 199 MPa, and on uneven roads it increased to 304 MPa, which is comparable to the yield point. It was found that the second form of vibration may cause stresses in the damage area, but the excitation frequency would have to be quite high. The probability of such a load and failure event occurring is low under operating conditions

Vliv geometrické neshody tahových svorek SB4 na jejich pevnostní a elastické charakteristiky

The paper presents comparative laboratory investigations of tension fastener models that attach rails to concrete sleepers. The aim of the paper was to assess the influence of geometric nonconformity of the actual industrial product that meets the PKP Polskie Linie Kolejowe S.A. requirements on the operation of a tension-fastening clamp under stress. Due to the cost and limited possibility of research of the actual industrial product, an additional objective of the research was to validate the usefulness of it in the comparative assessment of the models. In the research, the authors used models of tension fastening clamps manufactured in incremental engineering technology (3D print) on scale 1:2. The properties of the fastening clamps (in their nominal shape) were compared (described in the PKP Polskie Linie Kolejowe S.A. documentation) with the fastening clamps of the actual shape. In the investigation, the authors have confirmed the negative influence of the non-conformance of the shape of the actual fastening clamps with the nominal ones.Článek představuje srovnávací laboratorní výzkumy modelů tahových spojovacích prvků, které připevňují kolejnice k betonovým pražcům. Cílem příspěvku bylo posoudit vliv geometrické neshody skutečného průmyslového výrobku, který splňuje požadavky PKP Polskie Linie Kolejowe S.A., na činnost tahové svěrky pod napětím. Vzhledem k nákladům a omezené možnosti výzkumu skutečného průmyslového produktu bylo dalším cílem výzkumu ověřit jeho užitečnost při srovnávacím hodnocení modelů. Při výzkumu autoři použili modely tahových upevňovacích svorek vyrobených technologií inkrementálního inženýrství (3D tisk) v měřítku 1:2. Vlastnosti upevňovacích svorek (v jejich jmenovitém tvaru) byly porovnány (popsány v dokumentaci PKP Polskie Linie Kolejowe S.A.) s upevňovacími svorkami skutečného tvaru. Autoři šetřením potvrdili negativní vliv nesouladu tvaru skutečných upevňovacích svorek s nominálními

Reproducibility Assessment of Zirconia-Based Ceramics Fabricated out of Nanopowders by Electroconsolidation Method

The repeatability of the material properties is required to ensure the proper performance of the engineered systems that are constructed using these materials. In this paper, an analysis of the sintered ceria-stabilized zirconia is presented. This material exhibited high mechanical properties, due to the mechanism of strengthening via phase transition. The reproducibility was assessed for the material made out of a starting powder produced by fluoride salt precipitation. To fabricate specimens, a novel electroconsolidation method was used, ensuring a high heating rate, relatively low sintering temperatures, and short holding time. Weibull analysis was performed considering the bending strength of specimens and their microhardness. The obtained values of both shape parameter m and scale parameter σ0 indicated that the ZrO2 stabilized with 5 wt.% CeO2 samples exhibited low variability of strength and hardness. The experimental evidence and statistical analysis reveal an influence of the m-phase, which has lower symmetry and therefore its addition makes ceramic weaker and softer. Furthermore, its progressive replacement by the t-phase, which has higher symmetry, makes ceramic both harder and stronger. Reducing the mol% increases the risk of the appearance of the highest addition of the monoclinic phase; increasing it is unfavorable from the point of view of the sintering process. Statistical and manufacturing evidence suggests that the choice of 5%/mol is optimal