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Open access

Andrzej Kurek, Adam Niesłony and Marta Kurek

Abstract

The paper contains a numerical analysis of interface zone steel-titanium bimetal obtained by explosive cladding method. Due to the waviness of the zone, and various properties of the constituent material of the materials type contain structural notch. Therefore it is important inter alia in terms of presentation of the results of fatigue are the maximum stresses that occur just in the area of the zone. In the paper the stress concentration factor and the proposed method of modelling the joint zone of a sinusoidal profile, characterized by the same coefficient of stress concentration at the actual profile.

Open access

Grzegorz Porembski and Janusz Kozak

Simulation of damage process of containership's side structure due to collision with a rock

This paper presents methods and results of a simplified numerical simulation of collision process of containership's side structure and a rock. Analysis of results of the modeling makes it possible to draw conclusions as to a character of the event as well as to estimate area and depth of damage caused by the penetrating rock, in order to select geometry of a filler and impermeable layer of 2nd protection barrier.

Open access

Z. Pater, J. Tomczak and T. Bulzak

Abstract

The paper describes a new method for producing stepped rail axles. The method is based on the skew rolling process. With this method, the product is formed by three tapered rolls located every 120° on the perimeter of the billet. Positioned askew to the centerline of the billet, the rolls rotate in the same direction and with the same velocity. At the same time, they get closer together or go apart depending on the desired cross sectional reduction of an axle step. In addition, the workpiece is shifted lengthwise relative to the rolls by the translational motion of the workpiece-holding chuck. In order to verify the designed method for producing rail axles, a series of numerical simulations were performed using the Simufact. Forming v.12 simulation software. The numerical modeling enabled the determination of maps of the effective strain and temperature in the finished product as well as variations in the loads and torques during rolling. The numerical results unambiguously confirm that the skew rolling method can be applied to form parts of considerable dimensions (the modeled axles had a length of 2146 mm and their maximum diameter was 202 mm).

Open access

Z. Pater

Abstract

Skew rolling is a metal forming technique which can be used for producing stepped axles and shafts. This paper investigates seventeen cases of rolling at varying process parameters by the finite element method. As a result, it is possible to determine the effect of the forming angle α, skew angle Θ, linear velocity of the chuck, v, billet temperature, T, rotational speed of the rolls, n, reduction ratio, δ and friction factor, m, on axial load (acting on the chuck), radial load (acting on the roll in the radial direction) and torque. The results will be used when designing a laboratory stand for skew rolling which will be constructed at the Lublin University of Technology.

Open access

Ondřej Bílek, Imrich Lukovics, David Sámek and Jana Knedlová

Abstract

Residual stresses lower the utility value of plastic parts. Determination of the induced stresses can help deal with them. Measurements are time-consuming and expensive. A new approach to measuring residual stresses, such as indentation measurement, can lead to the simple determination of residual stresses. The paper shows the relationship between the condition of injection moulding, the subsequent residual stress, and hardness through thickness. The computer model displays the field and magnitude of residual stress in the samples. The model results are then compared to measured parameters after indentation and the magnitude of residual stress determined by the standard hole drilling method.

Open access

J. Bartnicki, J. Tomczak and Z. Pater

Abstract

This paper presents results of numerical calculations for the rolling process by means of three tools of stepped shafts from aluminum alloy 7075. Forming with the usage of tools with three different wedge spreading angles underwent analysis. In the paper, the obtained distributions of stresses, strains and Cockcroft-Latham damage criterion were given. Moreover, the influence of the wedge spreading angle on shape faults presence in the obtained product was determined. At the same time, the force parameters, which play a crucial role in the designed experiment, were analyzed.

Open access

J. Tomczak, Z. Pater and J. Bartnicki

Abstract

This paper presents results of theoretical and experimental research on skew rolling process of balls with diameter ;30 mm in multiple helical tools. Numerical analysis of the process was conducted basing on finite element method (FEM), using the commercial software Simufact Forming in version 10.0. Simulations were made in the three-dimensional state of strain with consideration of complex thermal analysis, due to which progression of the products shape was determined. Distributions of strains and temperatures as well as the process force parameters were also determined. The results of numerical calculations were experimentally verified in laboratory conditions. The obtained results confirmed the possibility of semi-finished products of balls type manufacturing by means of rolling in multiple helical impressions.

Open access

J. Bartnicki and J. Tomczak

This paper presents the forming method of head toothing with the application of rolling extrusion technology. Tools numerical models were used in numerical calculations. The presented numerical results concern metals flow kinematics, distributions of stresses and strains. Determined in the process technological parameters of head toothing forming allow foreseeing real material flow in the experiment planned for conducting.

Open access

J. Piwnik and K. Mogielnicki

Abstract

The main aim of the paper is an evaluation of the real impact of a container surface roughness on metal plastic flow in the forward microextrusion process. For the purposes of experiment a specially designed and constructed by authors toolkit was used. Analyzed material was an annealed aluminium wire with 1,7 mm in diameter, with a stress-strain curve defined. Toolkit contains two experimental models of containers and rectangular dies with the same dimensions, differing only in the containers roughness degree. In order to determine the degree of the containers top layers asperities a roughness profiles with using laser microscope were made for each. Punch pressures have been calculated while forward extruding. In the next step the deflection of parallel lines marked at the samples longitudinal sections were analyzed. The extruded samples were submitted to the microhardness testing. Numerical analyses of analogous microextrusion processes have been also conducted. Container surface roughness was modelled as a rigid triangular wave with a zero friction factor at the interface m =0. Punch pressures and shapes of extruded samples flow nets were determined. Conducted investigations revealed the possibility of receiving products with different mechanical properties obtained by the container roughness assorting.

Open access

Roman Gogola, Justín Murín and Juraj Hrabovský

Abstract

This paper contains results of transient analysis of airflow around the ACSR power line cross-section in unsymmetric multi-span. The forces applied to the power line are obtained from CFD simulations, where the wind induced vibration is studied. Effect of these forces to the maximal displacement of the power line and the maximal mechanical forces in the points of attachment are studied and evaluated.