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The paperpresents an optimal design and computational solution of truss structures consideringstress concentrations in welded joints. The calculation approach for precise analysis of welded joints using finite element method is introduced. The standard finite element analysis of the truss structure is followed by a special calculation procedure. The procedure is based on the known method of sections. Each member of the truss structure joined at the point under investigation is sectioned off the entire structure. In the next step, a new detailed finite element model of the welded joint is created. These analysis results allow define the stress concentration factors for technical problems of this type. Finally, a specific optimization procedure for design of structures based on the principles of discrete optimization is shown.

Progressive welding technologies based on high energy density welding process such as electron beam welding allow joining two materials without consumable. The nature of the process is the deposition of energy to the small areas, which leads to the creation of a narrow heat-affected zone (HAZ). Therefore, a prime example of surface weld defects in the case of the beam electron welding technology are cracks in the material. The article is focused on the preparation of a computational model that comprises a precise description of welding joint shape. The accurate model description was acquired using 3D scanning. In the next step, the data are subsequently modified in MATLAB and ADINA for model simplification. The performed analysis of results shows a significant influence of the weld surface on the occurrence of stress concentrations in the weld zone.

Rexroth systems are the right solution to move materials and it ensures a smooth transfer of material along the tracks Modern conveyor system is often used in industrial automatization. Presented system offers a full and diverse range of custom conveyor types and solutions. Designed conveyor system is an example of the use of aluminum profiles for students of secondary industrial school as a teaching tool.

The work presents the methods and solutions of the optimizing design of the truss and beam structures subjected to the cumulative fatigue damage. Two basic approaches used in the optimization of mechanical systems are presented in the paper - the so-called direct search methods and the gradient methods. A short comparative and gradient approach was made. The aim was to minimize the weight of the truss or beam structure with restrictions affecting the prescribed fatigue life. The computational model assumed only quasi-static loading with different number of cycles.

The paper deals with implementation of the optimizing process into multi-axial rainflow analysis and cumulative damage calculation. It’s presented computational program FEA_FAT compiled in MATLAB. Stress analysis is realized by finite element procedure and the cumulative damage can be calculated by using two fundamental ways – critical plane approach and so called integral approach. Testing example presents random stress analysis and damage prediction of a simple FE model with non-proportional loading.

The aim of this paper is to investigate the influence of technological parameters of the welding process on the level of the residual stresses, distortions, and phase proportions. The preheating temperature and the eccentricity of the weld path are taken into account. The Visual Weld tool from ESI Group was used for simulation.

The article deals with the design of compactor for a backhoe loader for middle size excavators. Construction of compactor clamp was designed from heavy gauge sheets which will be welded. For expansion of penetrating into thickening soil there were segments designed on drum. From the point of fatigue during comparison of reached maximal tensions and comparison of these values for several loaded alternatives from Wöhler curve was defined static safety factor.

T-joints are often used in large-scale welded constructions. The use of a laser beam for welding allows to create joints using various techniques. Used welding method affects the shape and size of heat affected zone, deformation of welded elements and consequently the quality of the joint. This work concerns the numerical modeling of the size of heat affected zone and welding deformations in T-joint obtained with two different welding techniques: single-side fillet T-joint and butt welded T-joint, called I-core welded joint. Numerical simulations are carried out in the commercial Abaqus FEA software, supplemented by an additional numerical subroutines which enabled the analysis of thermomechanical phenomena occurring in welding process. Mathematical model of a moveable welding source and the description of heat source positioning relative to the edges of the connected elements are described in numerical subroutines. The material parameters of austenitic steel are taken into account. The size of deformations of welded joints are determined as well as the influence of two different joininig techniques of T-joint on the amount of generated welding deformations are analyzed and compared.

The main idea of this paper is to compare the results of FE analysis and data obtained by experiment for identification of residual stresses in welded high-strength steels. The DOMEX steels welded by two technologies are compared – steel welded with laser beam and steel welded by electric arc. Residual stresses at the surface and just below the surface were evaluated using X-rays at predefined points. These data were subsequently processed in MATLAB and evaluated. FE analyzes were performed in software SYSWELD and ADINA.

Automotive industry is the one of the most rapidly developing sector of engineering. Using of new, progressive materials can make significant benefits because of growing durability and reducing weight of structural parts, which can lead to the materials and fuel savings. The authors of this paper discuss fatigue characteristics on arc metal welding process of high strength steels STRENX 700MC obtained in low cycle region (N approximate to 1.10(3) divided by N = 1.10(7) cycles) at low-frequency loading (frequency approximate to 35 Hz, T = 20 +/5 degrees C, R = -1). Authors compares results of their own experimental works and subsequently discus these result and their possible effect on the fatigue lifetime of these steels.

The paper presents a calculation model for simulation the technological process of inductive bending of pipes. In the case of an incorrect combination of geometric bending parameters (pipe diameter, bend radius and pipe wall thickness) occurs the corrugation of the inner part in the pipe bend. The proposed calculation model for the ADINA FE software allows for a relatively short time and at low cost to predict the emergence of corrugation.

The paper deals with the implementation of the chosen fatigue damage criterions into FE analysis. Our study considers a shell finite element structural analysis in conjunction with the multiaxial rainflow counting and the fatigue damage prediction. The computational analysis considers stochastic response under random excitation in time domain and damage calculation based on so called critical plane approach (CPA).

The article presents the theoretical and computational analysis of the fatigue tested specimens loaded by bending and torsion. The testing device allows loading by constant turn of the clamping parts. The stress and strain magnitude in test depends on the material characteristics and shape of the specimen. The calculations are realized by finite element method (FEM). The obtained results are verified with the experimental measurement applying the optical system ARAMIS.

The paper describes the process of casting ingots from the model material into a special mold made for these tests. The material was chosen stearin, which proved to be suitable for this type of laboratory test. During the solidification process of the ingot model under laboratory conditions, it was observed how gradually the layer formed on the contour of the casting. Gradual cooling of the ingot resulted in a decrease in the volume of the liquid phase in his body. The fog is readily observable by the naked eye and this is manifested by the formation of a gap between the ingot mold wall and the ingot body. A silicone oil has been used as a separating melt separating layer and the wall of the ingot that has reliably fulfilled this task. Casting was done in two ways, with a standing and lagging mold. The process of filling the cavity itself was to create conditions for the linear flow of the melt. Observation of the ingot after its solidification confirmed the fact that the filling of the cavity proceeded under such conditions in terms of the melt flow rate.

High strength low alloyed steels are nowadays an important group of engineering materials, with numerous industrial applications. Properly chosen chemical composition together with the thermomechanical processing allow to reach high mechanical properties, while the carbon content is maintained low. Resulting microstructure is therefore sensitive to the amount of the heat introduced to the metal during welding. During welding procedure, softening phenomenon can occur in the heat affected zones and it could lead to the degradation of the mechanical properties of the final joint. Nowadays, welding technologies based on the high energy electron beam are able to produce weld joints with very narrow heat affected zone. In this study, authors compare mechanical properties and the microstructural evolution in the heat affected zone of the GMAW and EB welded joint of the DOMEX 700MC HSLA steel. The carried out experiments showed that both evaluated technologies are able to produce joints with appropriate mechanical properties. Welded joints made by the EBW technique showed slightly better mechanical properties of the whole joint, as a result of the narrower HAZ.

The goal of this paper is to present the optimization of the vulcanization compactor pressure plate construction design. The basic factor for the mechanism functionality is the required stiffness compliance. The total construction stiffness has an influence on the vulcanization form tightness. Several solutions of the pressure plate have been proposed in the initial phase. Each proposal has been optimized in order to minimize the pressure plate weight meeting the conditions of the maximum displacement and the maximum allowed stress. The best solution has been chosen on the base of the evaluation afterwards. The multisoftware approach using ADINA and MATLAB software was used to perform FE analyzes.

In this work, there are published results about fatigue endurance of ductile cast iron obtained at high-frequency sinusoidal cyclic push-pull loading in the ultra-high cycle fatigue region. The main attention was focused on the fatigue lifetime data scatter caused by the influence of microscopic casting defects (microshrinkages, microbubbles, microcracks, non-metallic inclusions and local clusters of big graphitic nodules).

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

The prediction of hardness distribution in the cross section of welded join made of S1100QL steel is performed in this study on the basis of analytical methods. Analytical CCT diagram and volume fraction of each phases of S1100QL steel as a function of cooling time t8/5 are determined. A numerical simulation of welding process is performed in ABAQUS. Thermal cycles and temperature field in welded joints are determined. Prediction of hardness distribution in the cross section of the joint is performed on the basis of obtained cooling times t8/5. Results of numerical simulations are compared with experimentally obtained results.