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The paper deals with the stress distribution and stress value in grinding wheels with ceramic binding obtained using the method of optically sensitive surface layer. The tests were conducted with the grinding wheels being loaded both statically and with inertial forces existing during rotation of the grinding wheel. The results obtained were compared to those concerning the dynamic strength of grinding...
In this paper, a new approximate method of determining fundamental solutions for thin plates on elastic foundation is considered. Various models of foundations (Winkler, Pasternak, elastic half-space) are analysed. The approximate fundamental solutions are obtained through the analysis of power series of their Fourier's transform images. In the inversion procedure from images to originals, the well-known...
In the paper, the measurement system of "crash-test" experiments was presented. The prototype system based on two laser transmitters (red light) with special detectors with electronic system was used as the sensor. The system became an option of much more expensive accelerometers. The advantage of the method presented is its simplicity as well as the possibility of high acceleration recording...
Spring-back is a phenomenon that seriously affects the quality of parts made by forming processes of metal sheets. The size of distortions of the formed part caused by spring-back depends on different factors, such as: material parameters and chemical composition, working conditions and tool accuracy. The present paper deals with an experimental research into the influence of such sheet material as...
The influence of the temperature rise of a sample on relationship between the flow stress and strain determined in a hot torsion test was evaluated. Measurement of temperature was performed for samples of austenitic steel OH18N9 and titanium alloy WT22 deformed at temperature of 900 C at a rate of l0, 100 and 1000 rpm with partial radiation pyrometer and a thermovision system. It was proved that the...
The quaIity of a weld in the tailor-welded blank is very important for the success of the forming operation. The mechanical properties of the weld metal can be determined by applying different methods, such as: parallel test, normal test, microhardness test. etc. In the present paper, the mechanical properties of the weld metal in a tailor-welded sheet made by joining similar metals were investigated...
The known criteria for predicting the ductile fracture during bulk-metal forming operations and their disadvantages are discussed. Then the authors present their own damage model that is based on the strainpath dependent ductile fracture criterion and the use of a formability limit function. The computation procedure is implemented into the Forge3 finite-element package and tested by performing the...
In this paper, an analysis of deformation geometry of copper single crystals tested in tension was performed. Based on a large body of experimental results it was found that the onset of deformation stage IV is connected with the change of dominant deformation system. The paper also suggests that the change of the dominant deformation system may play an important role in the onset of the deformation...
The paper presents the results of experiments carried out in order to evaluate the plastic workability of Ti-48AI-2Cr-2Nb alloy subjected to hot compression tests. A significant influence of deformation temperature and, first of all, of the heating conditions on the results obtained has been shown. It has been found that deformation conducted under appropriate conditions and coupled with recrystallization...
The article is an attempt at showing how the theory of fuzzy sets may be used in explaining nonmonotone behaviour of the tool-life function. The results obtained in orthogonal turning of Stellite cobalt alloys served as a basis for presenting rules underlying the so-called areas of undetermined chip formation and for determning local extrema of the function. The fuzzy set theory is presented to the...
This paper describes a full-scale static test conducted on a corrugated steel culvert with 2.99 m span and 2.40 m in height. The test was carried out in the Bridge and Road Research Institute, Wrocław Branch, Poland, in 1998 for a Norwegian producer of culverts. The standardized railway load eon figuration UlC 71 for Europe was applied at various soil cover (from 0.3 m to 1.0 m). Several full-scale...
The study presents the results of examining the distribution of strains and stresses in the normal cross-sections of bended gypsum beams, dry prepared, made of building gypsum pastes at water-to-gypsum (W/G) ratios equal to 0.5, 0.6, 0.8, 1.0 and 1.5. The strain was measured by the strain gauge method, whereas deflections of the beams were measured with displacement sensors. Strain distributions were...
In 1928, Paul Katz (an employee of the Technische Hochschule Breslau) at the end of his paper “Die älteste eiserne Straßenbrücke des Europäischen Kontinents” [1] wrote: “If we have managed to provoke an interest of the mentioned institutions (Technische Hochschule Breslau, German Museum of Technol-ogy in München, authorities of the city of Breslau) in preservation of the bridge in Laasan (Łażany),...
In order to calculate the parameters soil-steel structure, a special software based on a 2D model is used. The concentrated forces of a bridge roadway generated by vehicles are being related in this model to a selected sector based on Boussinesq’s theory. This theory, however, does not fully confirm the work effect (internal forces) of soil-steel structures as flexible structures cooperating with...
The way in which a new road bridge made from Super Cor corrugated steel plates was tested during the three stages of its construction is described and the test results are presented. In construction stage I, the bridge was loaded with backfill and in stages II and III, with two ballasting vehicles. The box bridge spans the Bystrzyca Dusznicka River in Polanica Zdrój (Poland). The span’s effective...
In the paper, special emphasis was put on the structural stiffness of car elements described by crashworthiness indicators can be calculated for various structures. The effect of crashworthiness parameters of different construction and profiles on the relationship between the energy absorption and the maximum collision force is given. One-and multi-layer, empty and filled with different-density plastic...
Bering capacity of RC sections subjected to bending and accentric compression and being under the influence of oil evaluated. Two stages of oiling up are considered: non-oiling up state and oiling up state after 12 months of subjecting the RC section to oil influence. Ultimate bearing capacity of reinforced sections influenced by minertal oils is evaluated numerically based on the diagrams of the...
The present paper focuses on the problem of the durability of bent RC beams strengthened with composite materials, subjected to cyclic loading. The theoretical model of determining fatigue life of the cross-section of the bent reinforced concrete beam strengthened with external, non-stressed CFRP strips is presented. The author's own propos al is to introduce the coefficient ofthe strip position effect...
A segment of a gravel column, I m high and 0.53 m in diameter, was modelled in a calibration chamber. The reconstituted sample was consolidated at a given confining pressure and then subjected to wdalload exerted by the upper and lower membranes. Volumetric changes in both membranes and in internal chamber were measured. Up to 2% vertical strain was reached and internal friction angle was evaluated...
The paper presents the method of analyzing static work of support zones in concrete composite structures. This method is based on MCFT (Modified Compression Field Theory). WhiJe designing composite beams, the author allows only such cases, where the appearance of the interface crack is precluded by the diagonal crack. The case of support zones with diagonal cracks and locally cracked interface has...
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