In the latest issue of our monthly magazine:

Jacek Mucha, Waldemar Witkowski: The experimental analysis of the clinching joints strength for aluminum alloy EN AW-5754 in O/H111 state sheets in multi-axis load conditions
The maximum joints strength in thin-walled structures, made by redrawing sheet metal, is depended on the joint load angle. The round clinching joints should be loaded to carry the shear force. However, in many cases it is not possible to transmit only the shearing force, and the joints are transmitting the multi-axis load (shear and tensile force). The joint mechanism destruction is depended on the force load angle. Therefore, an important issue is to study the joints strength in multi-axis load conditions.
In this paper the results of the experimental analysis of the clinching joints, formed by using the round rigid die, strength were presented. The sheet material was an aluminum alloy EN AW-5754 in O/H111 state. The joint samples were tested with different values of the force load angle – from 0° to 90° with changes of 15°. According to the ISO 12996-2013 standard the structure of the joint strength were presented. The approximated curve of the joint mechanism destruction was determined.

Paulina Działak, Eugeniusz Rusiński, Jacek Karliński, Mariusz Ptak: New trends in the examination methodology of the mining machine operator safety
Analysis of the accident situations involving mining machine operators, that ensued in the underground mines over recent years indicate a necessity of their safety enhancement. Intensive exploitation on the ever larger depth increases the frequency of the unwieldy phenomena acting inside of the rock mass, posing a great risk for miners working in the underground mines. Nowadays, human body of the mining machine operator during obligatory safety examinations is substituted by the Deflection-Limiting Volume (DLV), which depicts approximate living space of the operator. Tests are considered positive, when DLV remains intact. However, there are no analysis considering the loads acting on the machine operators during the rock burst and all the phenomena caused by this effect in the underground mines. To this end, standard DLV model will be replaced with validated, numerical dummy. All tests will be proceeded with the use of most recent numerical methods, combining various numerical codes (coupling). This will enable to obtain more precise and closer to reality results, what may significantly influence on the safety enhancement in mines.

Krzysztof Kujawa: The influence of mold shape on the linear contraction of the alloy EN AC-48000
The paper presents results of research on the phenomenon of linear shrinkage and cooling silumin. In this study, metal molds mapping casting circular cross-section vertical rod (fixed or variable) were used. Use of two variant forms guarantees comparable cooling conditions in obtaining spasm of ideological freedom (form convergence of 1:100, unshared) and inhibits the contractions (as a cylindrical joint) only the surface of the mold. Basing on the recorded temperature changes and changes of the axial dimension of the casting mold and solidification of the test set, certain intensity and the change of the linear shrinkage coefficient of linear expansion of heat as a function of temperature were set. Results of tests of linear contraction in the forms with convergence and without it (cylindrical) were presented.

Krzysztof Puchała, Elżbieta Szymczyk, Jerzy Jachimowicz: FEM design of composite – metal joint for bearing failure analysis
The constant attempt to obtain as low aircraft mass as possible is the reason for using material of high specific strength (or stiffness) in the aerospace industry. High strength steels, titanium or aluminum alloys (e.g. 2024T3) and composite laminates (e.g. CFRP or Glare) are the examples of such materials. Dissimilar materials in aircraft structures provide a necessity of composite and metallic components joining. Various techniques are used to connect the skin with the stiffening elements: mechanical (riveting, bolting), adhesive (bonding and occasionally welding) and hybrid (where both above mentioned methods are used). Making holes is a necessity for mechanical joints. The holes are the areas of high stress concentrations and they determine load capability of the whole structure. However, mechanical joints used for decades are proved to be reliable. They can be assembled and applied in very rough conditions since they are less sensitive to environmental effects. The goal of the work is development of a mechanical metal-composite joint and failure analysis of the composite part. The double-shear joint is analyzed. Both analytical and numerical calculations are performed.

Łukasz Morawiński, Andrzej Kocańda: Reconstruction of 3D surface geometry of aluminum sheet undergoing the process of V-bending
This article presents a reconstruction of 3D aluminum sheet surface subjected to a process of V-bending. It discusses the changes on the surface of V-bent specimens. A parameter identifying the risk of sheet metal failure has been proposed.





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