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Abstract: Deformation measurement experiment has been undertaken where a concrete structure was subject to controlled loading. Concrete plate was loaded with hydraulic cylinder PZ 100 up to 42 kN. Nikon total station ser. 720 and camera Fuji Pro S3 have been used to make measurements at critical points during each additional load. A hydraulic computer operated cylinder was used for load increase. The use of total stations for deformation measurements is quite often, but the combination with digital photography is rather new and very suitable technique. It offers the capability of simultaneous monitoring of a large number of signalized or non-signalized points with very low root mean square error of 0.16 mm in geodetic method 0.7 mm in photogrammetry, respectively. The concrete plate was modeled and the comparison with the geodetic, photogrammetric and hydraulic method was made.
Keywords: deformation measurements, geodesy, digital photogrammetry
Published: 31.05.2012; Views: 1637; Downloads: 31
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Abstract: At the Faculty of Civil Engineering, the University of Maribor, in the Centre for Geodesy, we have been primarily dealing with the study of displacements and application of results on deformations and mathematical analyses for the last 10 years. According to these results, we wanted to find a connection between displacements and resulting deformations in mathematical terms. For this purpose, experimental load-bearing test of a concrete girder was carried out step by step up to crack. Additionally, concrete girder was analytically modelled and also photogrammetric, geodetic, and physical methods were compared. During the process of analyzing the results, further polynomial interpolation was performed through which the displacements in the intermediate stages were calculated. Polynomial interpolation can also help in accomplishment of load-bearing experiments of larger structures.
Keywords: geodesy, vertical movement, deformation, mathematical analysis
Published: 31.05.2012; Views: 1050; Downloads: 7
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Abstract: This contribution presents the results of the analysis of permanent deformations of gravel in the Mura region under repeated loading. The purpose of the analysis is to forecast the development of permanent normalised axial deformations ▫$/epsilon_1^{p*}$▫ regarding the number of loading cycles N and appurtenant stress states during cycling loading. The analysis used the results of tests performed by ZAG Ljubljana and Faculty of Civil Engineering and Geodesy (FGG) of the University of Ljubljana [1]. The analysis considers five types of stonematerials of different quantity of crushed grains in the mixture and of different water contents. Four types of stone materials are mixtures of different portions of crushed grains larger than 2 mm (Dcr = 87.7 %, 58.9 %, 32.6 % in 0 %), and of the water content around w = wopt - 2%. The stone material with portions of crushed grains larger than 2 mm Dcr= 58.9 % is analysed also for water content w = wopt + 0.7 %. The results of the analysis are deformations expressed as a function of the number of loading cycles N, and a spherical component of the repeated loading p and a distortional component of the repeated loading q. The results can be presentedas deformation surfaces in the ▫$/epsilon_1^{p*}$▫ - p - q space for an arbitrary number of cycles N. The relation between the spherical stress component p and the distortional stress component q, at arbitrary values of axial permanent deformations ▫$/epsilon_1^{p*}$▫, gives a failure envelope, and the so called deformation envelopes in the p - q space. The failure envelopes and deformation envelopes are given separately for five types of stone material. The deformation envelopes are low at small values of the axial permanent deformation ▫$/epsilon_1^{p*}$▫ When permanent axial deformations grow, the permanent deformation approaches the failure envelopes. The failure envelopes for individual types of stone material agree with research results performed by [1]. The analysis of permanent deformations also shows their dependence on the portion of crushed material Dcr in the mixture of crushed and uncrushed stone material. The deformation envelope for uncrushed stone material is situated in the lowest position, regarding the portion of crushed material in the mixture. With an increased portion of crushed material in the mixture of crushed and uncrushed stone material, the deformation envelope is also higher, similarly to the lawfulness of failure envelopes. The relation of failure and deformation envelopes is mathematically established as a function of the portion of crushed grains larger than 2 mm. The comparison of stone material results for different water contents shows that a minimal increase of water content above the optimal one essentially increases deformation.
Keywords: building materials, Mura river gravel, cyclic triaxial tests, granular base material, permanent deformation, normalized axial permanent deformation
Published: 01.06.2012; Views: 1073; Downloads: 28
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Abstract: This paper presents computer simulation of the forging process using the finite volume method (FVM). The process of forging is highly non-linear, where both large deformations and continuously changing boundary conditions occur. In most practical cases, the initial billet shape is relatively simple, but the final shape of the end product is often geometrically complex, to the extent that it is commonly obtained using multiple forming stages. Examples of the numerical simulation of the forged pieces provided were created using Msc/SuperForge computer code. The main results of the analysis are deformed shape, temperature, pressure, effective plastic strain, effective stress and forces acting on the die.
Keywords: forging, computer simulation, finite volume method, deformation, stresses, material flow, industrial applications
Published: 01.06.2012; Views: 1123; Downloads: 66
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Abstract: Components and structures exposed to elastic dynamic loading respond with elastic strains on the surface of the material. Mechanical response could be monitored by deformations on the surface. The measurements and monitoring of these parameters could be performed with electronic devices for on-line measurements, controlled by computerized systems. In the case of fatigue crack initiation and propagation the cyclic strain amplitude deviated from initial strain response (mean value and amplitude). Implementation of appropriate monitoring system supported by computerized programs for evaluation, analyses and activation represent important means to safe service component or construction. To evaluate flaw depth growth, the strain gauge measuring sensors could be used. These sensors measure surface deformation relaxation due to flaw depth growth. The monitoring of the material under cyclic loading could be performed with experimentally determined calibration curve, representing deformation on the surface and depth of the semi-elliptical crack growth on the surface or cross section of the material. The goal of this paper is describe electronic device and experimental procedure in order to determine calibration function.
Keywords: deformacije, elastičnost, rast razpoke, fatigue crack growth, surface deformation meaurement
Published: 10.07.2015; Views: 712; Downloads: 63
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