Papers by Keyword: Deformation

Abstract: Forming a metallic sheet along with the consideration of computer simulation and experiment had benefited the milling industry for a long time. The ideal forming, without an error, is a concerning topic. So, the computer simulation had the advantage then direct forming. To observe the results before doing the real experiments simulation comes handy. Which helped to set the parameters for the milling process for the single point incremental forming (SPIF) process. For milling, a CAD design was converted into a 3D model. For this, a conical shape of 3D modeling was made in fusion 360. After onwards, it was simulated for finding the maximum depth for the cracking point. Next for the experimental part, the maximum forming depth was considered, and used lubricant grease for reducing friction. While forming with the grease, the impact of parameters was also changed. Throughout the process, an optimization approach was set to reduce the cracking areas for the G-code. Along with the lubricant use, smooth milling finished surface was observed. To reducing the depth forming errors, an optimization approach was introduced in this research.

Abstract: This work emphasize on utilization of fly ash in to novel aluminium alloy (Al-2024). The Al-2024 alloy and composites (≈10%flyash) prepared by stir casting technique. The composites is cold forged and identified properties (mechanical, structural and stress distribution in component). Upset tests at room temperature, during the deformation process, provide representative behaviour. The metallographic structure of alloy revelled dendritic and composites shows fine spherical prime segment split and regularly dispersed intermetallic compounds. The stress intensity and distribution of temperature were examined in depth at different input combinations. Compression tests were conducted on Ø 12 mm cylindrical specimens at an H/D ratio of 1.0 and 1.5 for alloy and fly ash composites (2, 6 and 10 wt %). In determining the forging load, the upset ratio defined as the mainly important factor. The strain in composites increased with increasing % of reduction in size and decreased with % of fly ash.

Abstract: This study is aimed at strengthening the working surfaces of the jewelry tool - scraper. This tool is used for fine cutting work. The object of research is a method of additional thermofrictional hardening of samples of jewelry tool - scrapers made of carbon steel tool grade U8A. In the course of work the complex of metallographic, mechanical and analytical researches of samples in an initial condition after hardening and low-temperature release which includes is carried out which includes:1) preparation of samples in the form of plates and their preliminary heat treatment;2) surface thermofrictional strengthening (STS);3) conducting metallographic analysis of samples; measuring the microhardness and depth of the layer with a changed cross-sectional structure of the samples after STS;4) analysis of the influence of STS on changes in the structure and properties of steel on the basis of the obtained results, as well as identification of the degree of its strengthening and the role of deformation.The methodology of experimental researches is presented. Photographs of samples and some equipment at different stages of the study are given. Data on the distribution of microhardness, photographs of microstructures in cross section of samples after additional strengthening are presented. The efficiency of strengthening of samples after use of additional processing is shown.

Abstract: Aluminum alloys are widely used in automotive industry due to their low density and good corrosion resistance. This category includes alloys based on AlSiMg which are suitable for load bearing parts operating under higher temperatures. This paper deals with analysis of influence of deformation parameters and heat treatment on structure and mechanical properties of EN AW-6082 (AlSi1MgMn) alloy manufactured by horizontal cast module technology. Casted rods were used as a billet, which was formed to defined height by hot open-die forging. Subsequently the precipitation hardening was used as heat treatment. Changes in microstructure were evaluated based on the metallographic analyzes performed by light optical microscopy and scanning electron microscopy using an energy dispersive X-ray spectrometry and electron backscatter diffraction. Mechanical properties were determined by uniaxial tensile test and hardness testing. The results showed, that due to the process parameters, no significant structural changes were observed in the surface layer of forging. However, microstructure is significantly inhomogeneous in the core due to the dynamic softening processes. Mechanical properties are increasing which is significantly influenced by the type and distribution of precipitates emerging during the artificial aging.

Abstract: Occupant safety is one of the critical performance criteria established in the aerospace industry. Several composite materials have been developed but the energy absorption properties are not yet satisfactory. This study investigates the energy absorption characteristics of aluminum tubes reinforced with coir-fiber/epoxy system at varying proportions (10-90%) according to the specifications of hybrid tube thickness compositions (10T, 15T, 20T) towards evolving a criterion for optimal performance. Finite element analysis was conducted in ABAQUS to determine the load–displacement response and the crashworthiness properties of the tubes while a representative volume element (RVE) model was formulated to obtain the elastic properties of the reinforcement phase. The results indicated that the incidence of high peak forces P_max is related to tube thickness variations where the 20T tubes were found to give the best performance, while the 15T tubes showed a superior performance under progressive crushing and presented the best responses for specific energy absorption (SEA). A multi-objective optimization plan was implemented and through the Pareto fronts, tube configurations (C20T60F), (C15T70F) and (C20T40F) were found to be most consistent with the design criteria. Results from experimental validation were found to be in close agreement with numerical predictions and satisfied the overall objective of achieving a good balance in lightweight design for crashworthiness applications.

Abstract: The mechanical behaviour of textile structures is one of their most important characteristics as far as their end use is concerned. Textile structures, fabrics, or yarns are often considered as continuous mediums apart from the fact that they are composed of some discrete elements, individual fibres composing yarns and yarns composing fabrics. This is known as the transition scale, a very important lock to be considered, to evaluate the real structure behaviour. In this context, this work presents some simulations of the mechanical behaviour of a fabric where the yarn is a continuum material. Particular attention was paid to simultaneous loading in uniaxial or biaxial extension and shear loadings. The results of numerical simulations, which show the deformed fabric unit cell under multi-load conditions, are coherent with experimental observations and encourage the authors to continue the present work with parametrical and inverse case studies.

Abstract: Nowadays, the availability of composite materials and their acceptable manufacturing cost, in addition to their high strength-to-weight ratio, has shifted the use of the materials from metal alloys to composite materials in the aircraft industry. In this paper, a comprehensive analysis of wing natural frequencies and deflection with regard to three different composite materials - carbon fiber, glass fiber, and Kevlar fiber - was conducted, and the results were compared with conventional metal alloys aluminum2024 and 7075-T6, while taking into account the anisotropic behavior of the composite materials. The results indicate that the metal alloys aluminum 2024 and 7075-T6 have the best properties, and consists of the most suitable materials for aircraft wings compared with other composite materials. In addition, the deflection of the wing using AL2024 was about 0.549 unit length and for 7075-T6 was about 0.547 unit length, which was almost less than half of the deflections of other proposed composite materials which are 1.252, 1.389, 1.293 unit length for glass fiber, Kevlar fiber and carbon fiber, respectively.

Abstract: A numerical simulation model has been established to obtain the deformation, strain and stress concentration of slab narrow side. The simulated temperature profiles of slab show a agreement with the results of measured temperatures by using infrared thermal camera. Moreover, the deformation, stress and strain of the slab have been investigated systematically, especially at the slab narrow side along the thickness direction. The relationship between the reduction amount and deformation, stress and strain concentration of slab narrow face has been investigated.

Abstract: Pipelines are widely used in industry for transporting oil and gas. Dents are one of the most common mechanical damage to pipelines due to external factors and significantly affect the performance of the pipelines. A dent is a permanent deformation of the circular cross-section of the pipelines. In this paper, numerical simulation using finite element analysis on API 5L X52 pipelines subjected to denting by a spherical indenter was carried out to determine the distribution of Von-Mises stress and permanent deformation. The given load was between the yield strength and ultimate strength of API 5L X52. The effect of indenter diameter and indenter displacement was studied. The results show that the indenter diameter and indenter displacement affect the value and area distribution of Von-Mises stress and permanent deformation.

Abstract: This paper is devoted to hot isostatic pressing (HIP). HIP capsule simulation software has been analysed. Abaqus has been proved the most appropriate simulation tool, which enables finite element analysis and allows users to define their own material properties via a special control program. Specific features of HIP simulation models have been evaluated. Powder densification model has been analysed and implemented. A control program has been developed to factor in elastic and plastic material behaviour. Preliminary simulations have been run for a one-element model and a capsule model.