Papers by Keyword: Uniaxial Tension Test

Abstract: The paper deals with the determination of the modulus of elasticity in tension for cementitious composites and comparing these values with the values of modulus in compression. It describes several methods, which are usually used for determination of modulus of elasticity of concrete and fibre reinforced concrete. In the experimental program modulus of elasticity in compression and tension of various types of concrete and fibre reinforced concrete were compared. The classic test with prismatic specimens was used for determination of the modulus in compression; a new arrangement of uniaxial tension test of cementitious composites was used for determination of the modulus of elasticity in tension.

Abstract: The paper deals with the issues of uniaxial tension tests of concrete and fibre reinforced concrete. Possible shapes of specimens and arrangements of the experiment are discussed, including the consequences arising from the adjustments. Behaviour of sample during loading, before and after initiation of the first crack is studied, stresses in the critical cross-section as well as loading methods are analysed.

Abstract: The paper deals with an investigation of tensile properties of concrete and fibre reinforced concrete using the test in uniaxial tension. This arrangement is technically more difficult compared to the commonly used bending test, but allows easier determination of strength-deformation parameters of material. The advantage of the test is the possibility of direct analysis of the post-peak part of the stress-strain diagram in tension. The article describes the recommended test arrangement and analyzes methodology of loading. Attention is focused on the critical phase of the loading process and subsequent evaluation of results. In the experimental research was compared strength and corresponding strain of specific fibre reinforced concrete, obtained in three-point and four-point bending test, and the uniaxial tension test. The results of this comparative study are presented in the conclusion.

Abstract: Materials used for the production of aluminum beverage cans must meet strict strength and plastic requirements. Meeting these requirements by manufacturers ensures minimization of defects in optimized production line, trouble-free operation and good efficiency of production. Depending on some factors, such as: chemical composition of the 3104 aluminum alloy, sheet rolling method, lubricant layer and cooling method, the final product may be characterized by different mechanical parameters. In this study properties of six types of sheets from four different suppliers have been measured. Thickness distributions have been analyzed both on the width and length of the supplied coils. Sets of samples have been prepared for the research, cut out from the coil in three directions 0°, 45° and 90° of the rolling direction. On the basis of the uniaxial tension tests, yield strength, tensile strength, elastic modulus and elongation have been determined. The results have been summarized taking into account their variable values depending on sampling directions. Forming limit curves have been defined for the examined sheets. In order to identify the effect of selected data on wall thickness of both final and semi-products, thickness measurements have been conducted for the drawn cups and cans on different forming stages.

Abstract: These paper aims to present an experimental study for determining the mechanical properties of woven fabrics used for airbags manufacturing. In order to realise the study, there were chosen two types of fabric, one that is coated with silicon and one that is uncoated. The experimental tests that were carried out were uniaxial tension tests for samples extracted on the warp and on the weft direction, the Bias test, a test specific for shear loads and the dome test, a test specific for biaxial loads. For the uniaxial tension test the force-displacement curve was obtained and the maximum values of the loads and the displacement. For the last two tests (bias test and dome test) there have been determined the maximum load, the displacement at maximum load, but also the local major strains obtained. All tests were carried out on a tensile and compression testing machine Instron 5587, while for measuring the main strains there has been used also the optical measuring system Aramis.

Abstract: The mechanical property of polyvinyl chloride (PVC) geomembrane was usually expressed using engineering stress-strain response in traditional uniaxial tension test. By failing to account for deformation of specimen during the test, the deviation of true stress and strain maybe caused from the test results. In this paper, the true stress-strain response of PVC geomembrane was investigated using uniaxial tension test. The photographic analysis method was used to measure axial and lateral true strain of specimen. The Poissons ratio and true stress were also acquired based on measured true strain in the test. Then the true stress-strain relationship was obtained from the test results. By comparing with the engineering stress-strain results expressed by traditional method, it can be found that the engineering stress-strain result is unreasonable. The engineering stress-strain expression easily leads to the underestimation of the true stress.

Abstract: The aim of this paper is to determine the mechanical properties of textile reinforcements laminated composite material and to establish the influence of thickness about these properties. The composite material used for this is a laminated sheet of HGW 2082. In order to study the mechanical behaviour of these kinds of materials we select two experimental tests: uniaxial test and bending test. For the uniaxial test we have measured the maximum load, the maximum extension, the maximum tensile stress and the maximum tensile strain. Also, using an optical extensometer we measured the major and the minor strains. For the bending test we measured the maximum load and the maximum bending deflection and the major and minor strains. After the uniaxial tension tests we can draw that we obtained the following results: the maximum value of the local major strain and equivalent strain decreases with the increase of the specimen thickness. After the bending test we can draw the following conclusions: the maximum value of the bending deflection decreases with the increase of the specimen thickness while the maximum value of the local major strain increases with the increase of the specimen thickness.

Abstract: Engineered cementitious composites (ECC) has good ductility, with its unique strain hardening and multiple cracking characteristics. Through the research of uniaxial direct tension performance and durability tests of ECC blending with polyvinyl alcohol (PVA) fiber, the tensile stress-strain curves, the freeze-thaw resistances and the impermeability of ECC were analyzed. The tensile stress - strain curve results show strain hardening of ECC achieved under the uniaxial tensile load; PVA fiber has good crack resistance toughening effect, can significantly improve crack resistance and deformation capacity of cementitious composites. The maximum tensile strain of the ECC is between 3800με to 8657με (20-50 times that of polypropylene fiber concrete) displays high toughness and large deformation characteristics. The freezing level of the ECC is higher than F300, which is ideal for the maintenance and reinforcement of concrete structures in cold regions. Domestic and imported PVA fiber can significantly improve the impermeability and crack resistance of the ECC.

Abstract: This research work presented the analysis of plasticity of high carbon alloy constructional steel in the conditions corresponding to plate rolling in a reversing mill. The deformation and temperature conditions occurring in the real process were reproduced during testing. Plasticity of the steel in the temperature range of 800÷1000oC and for three different strain rates of 0.1, 1.0 and 10 /s was determined in the course of experiments. The research was carried out using the Gleeble 3800 physical simulator of metallurgical processes with the Pocket Jaw module, to estimate the steel plasticity in the uniaxial tension test to the failure strain of the sample. The performed research work enables to determine the optimum temperatures and size of the critical deformations which should be taken into consideration when designing the process of the tested steel rolling in order to avoid formation of internal and external cracks.

Abstract: The mechanical properties of various parts of the welding-line material are different, while they play very important role in the welding structures, such as the differences of the melted part and the temperature-affected part. In this paper, a non-contacting laser based technique, ISDG (Interference Strain Displacement Gauge) method, is applied to find out these property differences on very small specimen. The testing is very successful and the whole stress-strain curves in such small scale are obtained on different parts of the welding-line material. The soften phenomena of the temperature-affected part is observed by the comparison of the Young’s modulus and yield stress between the melted part and the temperature-affected part.