Papers by Keyword: Torsion Test

Abstract: In recent years, the studies on producing data on physical and mechanical properties of Malaysian timber specimens have evolved from small clear specimen to structural size specimen, where most of the research method was based on the American Standard Testing Manual ASTM D198. Numerous data regarding mechanical properties on structural size specimen have been produced through this method, such as bending and compression test. Unfortunately, studies on shear properties on structural size timber are very scarce. It has reviewed that the global timber researchers are focusing to produce data on shear properties of European timber species such as Oak, Spruce and Pine where both shear strength and shear modulus data were obtained from bending and torsion test. Furthermore, from the review of the existing literature, it is clear that there is no proper studies focusing on development of shear properties of Malaysian tropical timber, especially torsion test in accordance with EN 408:2010. Therefore, the aim of this study is to investigate the shear properties (shear strength and shear modulus) of Malaysian Tropical Timber in large size.

Abstract: The most important parameter, characterizing the rheological properties of steels and alloys, is the strain resistance. The new method of testing cylindrical specimens for torsion with variable grip’s accelerations is proposed (application No. 2018132149 of 07.09.2018 for the patent of the Russian Federation for the invention). This method is designed to study the rheological properties of steels and alloys mainly in a hot state. However, this method is universal and can be used to determine strain resistance of materials in a cold state. The article is devoted to the applicability evaluation of the proposed torsion testing method, to study the rheological properties of materials in a cold state. It’s done on the basis of comparison of the hardening curves, obtained during the testing of specimens for tensile and torsion. The CrWMn steel was used. The results show that the hardening curves obtained during the torsion and tensile tests are close, and the yield stress values differ by about 3%. It can be assumed that the developed method of torsion testing allows to obtain reliable values of the material’s strain resistance in a cold state.

Abstract: Torsion tests allow to study the rheological properties of various materials, including properties in hot state, as well as they allow to conduct physical simulations of real material forming processes, including processes of intensive and alternating deformation. However, it is often a question what size the specimen should have to perform torsion test accurately. The article aims to study the influence of cylindrical specimen size on the distribution of deformation during torsion test. For this purpose, computer simulation of the torsion testing process was performed. The influence of the relative length of the specimen gauge on the deviation of the actual values of the effective strain from the calculated values was quantified. It is shown that the error in the calculation of the effective strain, based on the values of the twist angle and the specimen gauge size, is of 4%. In order to verify the results obtained by computer simulation, the physical simulation was performed. It is shown that the distribution of deformation along the length of the specimen gauge is also significantly influenced by the accuracy of specimen manufacture, as well as the specimen material. In some cases, the error in the calculation of the effective strain, based on the values of the twist angle and the specimen gauge size, can reach more than 80%.

Abstract: The article provides an overview of existing methods of testing specimen for torsion, in order to determine the rheological properties of materials. In addition, the approaches to the post-processing experimental data, obtained in the form of torque-twist angle curve, are reviewed. It is shown that there is no universal and reliable method to study the rheological properties of materials that are sensitive to the strain rate. This paper proposes the new testing method that takes into account the effects of strain rate hardening initially. This method is that the torsion tests are carried out with the variable grips acceleration. The post-processing of obtained experimental data can be carried out with the use of modified Nadai method. In addition, with the use of mathematical modeling it is shown that the new method is reliable, regardless of material properties. The application for invention of the new testing method No2018132149 was directed in Federal Institute of Industrial Property on September, 7, 2018.

Abstract: Torsion tests allow studying the rheological properties of materials over a wide range of strain and strain rate values, as well as temperature. A key moment in construction of hardening curves is the interpretation of experimental data, which are usually the torque – angle of twist curves. However, there is a number of independent methods to obtain interpretation of experimental data. In addition, there is no single approach to determining the degree of equivalent strain in torsion test. The aim of this paper is to review existing hardening curves definition methods in torsion test and to examine them with the use of finite element modelling.

Abstract: The paper presents the results of the study aimed at determination of plasticity of hard-deformed aluminium alloy grade 5019 in terms of parameters characteristic for the process of extrusion. The examinations were carried out in hot torsion test. Using the developed mathematical model of the analyzed alloy the mathematical modelling of torsion test was also performed.

Abstract: This paper analyzes the performance of fiber carbon composite core rod under torsion load through finite element simulation and full-scale test, providing technical basis for the failure mode and key parameter design of fiber carbon composite core rod.

Abstract: The present paper provides a picture of metallographic and plastometric research in the border areas of steel production and forming. The focus of the paper is simulation conducted in SETARAM plastometer. The SETARAM plastometer used in the experiments has been modified recently. The changes concerned predominantly its temperature measurement and control devices. The lower limit of its operating temperatures was reduced to approximately 400 °C. The purpose of the most recent upgrade was to allow investigation in the region of steel brittleness related to loading in their freezing range. It will be possible to explore the behaviour of steels under the conditions of continuous casting processes, solidification in crystallizers and deformation during solidification. Microstructures of various types of steels are presented upon small continuous deformation applied at high temperature, which lead to partial melting and resolidification of test bars. Various types of sheet rolling simulations with reduced finish temperatures conducted in the plastometer are described. Approaches to evaluating continuous torsion tests to fracture in the field of basic research into materials plasticity are presented as well. In terms of interrupted tests, the importance of the anisotropic interrupted test as a source of information for research is touched upon. In particular, demonstration is given of the potential for finding transformation temperatures governed by deformation in the 1.0583 steel grade. A physical simulation procedure involving strain-induced ferritic transformation has been developed on the basis of results of tests. Mechanical properties were measured on specimens processed in the simulation. Microstructures resulting from the thermomechanical simulation are discussed.

Abstract: This paper presents determination of flow curve of steel by using multi regression analysis based on only few experimental points of torsion test. It is necessary to know the flow curve of the formed metal and the best way to obtain one are different experiments such as tensile, upsetting or torsion tests. In the paper torsion test was used for obtaining the flow curve. In torsion test a cylindrical specimen is twisted by torque acting around its axis. Experimental data of torsion test were processed by determination of statistical characteristic of experimental results.

Abstract: By conducting simple tension and torsion tests to material, constitutive equations of one dimension are obtained. Plastic theories of continuum mechanics are used for analyzing deformation behavior of the material after yielding. Here, material is presumed to have isotropic hardening characteristic. By using Mises loading function and the associative flow rule, the derivations are made to extend the constitutive equations of one dimension in the simple tension and torsion tests to that of multi-dimension and obtain the plastic constitutive equations of the material in complex stress state , respectively.