Papers by Keyword: Simple Shear

Abstract: Tire simulation gradually becomes an important mean to ensure the quality of the tires. In order to guarantee the reliability of the analysis, the study on the method of obtaining the material parameters is also increasing. According to tire force situation of actual work, the acquisition method of tire rubber parameters based on simple shear test and its application in finite element analysis were studied in this paper. In this research, the international advanced dynamic mechanical analyzer was used to test the tire rubber, and the experimental results were processed by Yeoh hyper-elastic model. The hyper-elastic parameters and thus obtained could be used for finite element analysis of tires, and the simulation results showed that these parameters could be used to simulate the tire performance. In addition, the results could also provide certain guidance for the design and manufacture of tire.

Abstract: Aluminium is a potential light weight alternative to steel for deep drawn sheet components, but generally does not compare well to steels in terms of formability. Research in polycrystalline plasticity indicates applying shear to rolled fcc alloys improves their deep drawability by favourably modifying their crystallographic texture. Such processing could be realised industrially by cold asymmetric rolling (ASR), but in order to gain detailed understanding of the influence of process parameters on the evolution and through thickness homogeneity of the texture a validated full field multi-scale model of the process is required. This study examines the ability of a hierarchical multi-scale approach to predict evolved textures for aluminium sheet subjected to a mechanical test exhibiting a deformation mode relevant for ASR, namely simple shear. The homogeneity of the deformation field is assessed with full field strain measurement by digital image correlation, and macrotexture is measured by x-ray diffraction. The discrepancies are discussed and further work to validate the modelling approach for simulation of texture evolution in the ASR process is briefly outlined.

Abstract: Through scanning electron microscope (SEM) observation on kinetic friction and static friction deformation, our data show that granular nanoparticles (commonly 60-80nm with diameter, d) are widespreadly distributions in narrow friction zones. Furthermore, the identification markings, such as nature, experiment and fabric orientation etc., usefully deal with the mechanical analysis,and the granular nanoparticle distributions in narrow friction zones could be subdivided into three kinds, i.e. simple shear, pure shear and rotational shear pattern. Additionally, note that under stress action physico-chemical phase changes might be respectively caused by internal cohesion and dynamic differentiation in the narrow friction zones. These analyses deduce that some few complex idea fields, including structural stress, physics and chemistry field, with spatial and temporal evolution exist in the narrow friction zones, moreover, they viably regulate the nanoparticle distribution.

Abstract: Object Stress rates to predict the behavior of material have been researched based on numerically and theoretically for researchers who study continuum mechanics due to its complexity. This study focused on the various objective stress rates which assumed the finite deformation theory. Eight object stress rates (Oldroyd, Truesdell, Cotter–Rivlin, Jaumann, Green–Naghdi, Eulerian, grangian, and logarithmic object stress rates) were introduced using continuum mechanics and analyzed to derive the numerical solution to the simple shear problem. Numerical results from each object stress rate were analyzed and compared with the results of the other stress rates. Finally, the appropriate object stress rate for the simple shear problem was determined based on the numerical results from eight objects stress rates.

Abstract: The flow stress behavior of a bake-hardenable steel during a few simple shear cycles is investigated using a crystal plasticity model. The simple shear test provides a stable way to reverse the loading direction. Stress reversals were accompanied with a lower yield stress, i.e., the Bauschinger effect, followed by a transient hardening stage with a plateau region and, permanent softening. The origins of these three distinct stages are discussed using a crystal plasticity model. To this end, the representative discrete grain set is tuned to capture such behavior by coupling slip system hardening appropriately. The simulated results are compared with experimental forward-reverse simple shear stress-strain curves. It is shown that the characteristic flow stress stages are linked to texture evolution and to the Bauschinger effect acting on the different slip systems.

Abstract: We present a model of severe plastic deformation of metals under the assumption of turbulence in their representative volume element. It provides simple and natural answers to a number of questions at the border between mechanics of solids and materials science.

Abstract: A hypothesis for two-stage character of deformation under load via the simple shear scheme is suggested. At the first stage in the shear strain range , where - the strain parameter, the metal microstructure changes in the way similar to that during elongation. At the second stage at accidental multi-scale rotative motions, similar to turbulent motions in liquids, take place in the metal. This stage of deformation is the proper simple shear. The results of experiments are presented, which testify in favor of the suggested hypothesis.

Abstract: The artificial aging response of Al-Mg-Si 6082 aluminum alloy is investigated over a wide temperature range. Samples aged to under aged, peak aged and over aged conditions are further subjected to plastic deformation by simple compression, plane strain compression and simple shear. The flow behavior and the corresponding hardening rates are documented. Equivalent stress – strain curves are generated for the three stress states for an aging temperature of 160oC. Strain reversal experiments in simple shear were carried out in order to characterize the Bauschinger effect. Strain path change experiments were also conducted, in which the gage section that was first deformed by simple shear was further deformed by simple compression.

Abstract: The finite element method is a widely used tool in sheet metal forming. The quality of the results of such an analysis depends largely on the applied constitutive model and its material parameters, which have to be determined experimentally. These data are relevant on the choice of the yield criterion among the wide range of options available in the commercial applications implementing the finite element method. Since the accuracy of material parameters estimation is therefore crucial, investigations were performed with an Al-Mg sheet alloy and a mild steel sheet to optimize a Miyauchi-based simple shear test. This method is one of the basic ways to investigate the plastic properties of a sheet metal up to large strains, which is very important for numerical analysis of sheet metal forming processes. Aim of the test is to determine the shear stress-strain correlation. In order to enhance the quality of the experimental results the detection of the deformation’s field, trough an optical measurement system, and the methodology for its evaluation are focus of the present study.

Abstract: The role of the deformation pre-history in high-cycle fatigue properties of copper produced by severe plastic deformation is discussed. The focus is placed on comparison of the structures and mechanical behaviours of two types specimens produced either by rolling or by ECAP, i.e. by the pure shear or simple shear mode, respectively. It is shown that the deformation either by simple or pure shear mode to the same equivalent strain results in alike mechanical properties, both monotonic and cyclic. The significant influence of the initial stages of strain hardening on fatigue is highlighted.