The problems of a material selection for making the boiler pipes in a responsible steam plant and the technology for their welding are considered in this paper. The boiler is screened, complex, radiating energetic plant, with the natural water circulation in the hanging steel structure. Based on the legal regulations, the mandatory periodic reparation of the most important components is performed. This is why the check of mechanical properties, for the used and new materials for eventual replacement and building-in was done, as well as the check of the prescribed reparation procedures. The components that were in exploitation were checked, since their properties change with time. Checking consisted of testing the tensile material properties at room and elevated temperatures, measurements of hardness and analysis of materials’ microstructures. Besides the experimental tests, the numerical modeling and analysis of the workload of the fluid transporting pipes was conducted. In that way it was established which material is optimal for manufacturing the boiler pipes

The paper presents a functionality investigation of the key dam elements based on finite element analysis. A detailed analysis of filtration processes, dam strength, and the surrounding rock mass was conducted. Dam elements whose potential damage could jeopardize the normal functioning of the embankment dam have been identified. A particular emphasis was placed on the analysis of dam elements that have been identified as weak points. A numerical analysis of the impact of individual grout curtain zone failure on leakage under the dam body, a strength analysis of the overflow section, as well as the analysis of the slope stability that can compromise the functioning of the spillway have been performed. To analyze the partial stability of individual structural elements, a new measure of local stability was introduced as the remaining load-bearing capacity. As a case study, the Zavoj dam, which is a part of the Pirot reservoir system in the Republic of Serbia, was used. Investigation revealed that local damage to the grout curtain will not significantly increase leakage under the dam body, the overflow section is one of the most robust elements of the dam, but the slope above the spillway can compromise the functioning of the overflow and thus the safety of the entire dam. Based on the analysis of the results of the remaining load-bearing capacity, the dependence of the spillway capacity on earthquake intensity has been defined. The established relationship represents a surrogate model for further assessment of dynamic resilience of the complex multipurpose reservoir system, within the scope of the advanced reservoir system management.

This paper presents a method for implicit stress integration of the Drucker-Prager material model with kinematic hardening. The stress integration of the material model is conducted using the incremental plasticity method, while the kinematic hardening of material is defined using nonlinear Armstrong-Frederick hardening. This type of granular material hardening occurs as a consequence of the cyclic loading effects, such as the seismic load. For this reason, this material model is used for the earthquake analysis in the soil mechanics. Yield surface of the material model changes its position under the cyclic loads in the stress space, whereas there is no change in the size of the yield surface in deviatoric plane. The developed algorithm of the material model has been implemented in the software package PAK.

Fotogrametrija je tehnika merenja 3D koordinata koja koristi fotografije kao osnovni metrološki medij. U radu je prikazana primjena fotogrametrijskog sustava na mjernim i kontrolnim zadacima u automobilskoj industriji. Ova beskontaktna...