Structure and mechanical properties of composite amorphous-crystalline Al-based materials synthesized by high pressure torsion.

The results of the structural studies and hardness measurements of bi-and three-layer samples obtained by high pressure torsion of melt-spun ribbons of Al-based alloys with amorphous and crystalline structures have been presented. It has been established that straining of amorphous ribbons results in formation of nanocomposite structure while that refinement of crystalline structure and increase of microstrains takes place in crystalline ribbon. It has been found that the hardness of the consolidated samples increases with the increase of the deformation level up to 4,7 GPa.

Challenges on contemporary architectural technology on durability of reinforced concrete structures

PurposeThis study aims to discuss the causes of short-lived structuring of contemporary buildings. The life expectancy of structures may be theoretically predefined during the state of the design. This time period, known as the service life of structures, is determined by the load or the deformation level at which irreversible failures of the bearing structure may occur. On the other hand, planned obsolescence and perceived obsolescence, observed in the western world since the first half of 20th century, are currently setting an economic reality and are part of an expanded framework that, apart from architectural structures, extends to all design fields. The effects of short-lived structuring on environmental and energy terms are presented and theoretical and experimental recommendations from the literature are cited, as well as recommendations that have already been successfully applied in some countries.Design/methodology/approachThis study aims to discuss the issues associated with short-lived structuring, durability and obsolescence of contemporary structures. For this purpose, theoretical and experimental recommendations from the literature are cited, via an extensive state of the art research.FindingsShort-lived structuring has been a field of research during recent years. Terms such as durability are being introduced into Design Codes, while trends like perceived obsolescence and environmental impact raise issues for research. Moreover, the results of short-lived structuring are becoming more and more apparent, indicating an unsustainable reality. Issues like maintenance of structures, sustainability in design, corrosion effects, repair techniques and building waste management are an important field of research among the engineering community. In this study, the parameters affecting the lifespan of contemporary structures have been discussed.Originality/valueThe effects of short-lived structuring on environmental and energy terms are presented and theoretical and experimental recommendations from the literature are cited. The parameters studied herein concern material properties and design approach but also environmental and energy-related ones.

Analytical and experimental study on shear performance of RCC beam elements reinforced with PSWC rebars: a comparative study

Early distress in RCC (Reinforced Cement Concrete) structures in the recent times poses a major problem for the construction industry. It is found that in most of cases, distresses in reinforced concrete structures are caused by corrosion of rebar embedded in the concrete. The HYSD (High Yield Strength Deformed) rebars which are used to offer excellent strength properties is detrimental to durability due to action of ribs as stress concentrators. Nowadays, concept of PSWC rebars (plain surface with wave type configuration rebars, formerly known as C-bars/mild steel rebar with curvy profile) is emerging to have a compromise between strength and durability. This investigation assesses the flexural behaviour of RCC elements reinforced with PSWC rebars. The flexural performance of RC beams of size 1000mm x 150mm x 150mm reinforced with PSWC rebars at 4mm and 6mm deformation level was studied by conducting test as per IS 516-1959 under four point loading. The performance of PSWC bar reinforced elements are compared with beams reinforced with mild steel rebars, HYSD rebars with spiral and diamond rib configuration to assess the viability of PSWC rebars to replace conventional reinforcement. The test results are validated by numerical analysis with the help of ANSYS software. Totally 15 beams are subjected to flexure test and the performance evaluators are first crack load, deflection at first crack load, ultimate load carrying capacity, deflection at ultimate load, load-deflection behaviour, load-strain behaviour and failure pattern. It is found that PSWC rebars as reinforcement in concrete beams enhanced the ductile behaviour of beams as compared to conventional HYSD and mild steel rebar beams. The energy absorbing capacity has increased significantly for beams reinforced with PSWC rebars when compared with conventional HYSD and mild steel rebar beams. The load-deflection behaviour and failure mode of PSWC rebars reinforced concrete beams were found to be similar to that of high yield strength rebars irrespective of deformation level. The analytical investigation from ANSYS software gave good agreement with the experimental results. It is concluded that PSWC bar has the potential to replace conventional HYSD rebar. Further study needs to be done to optimize the profile level and stirrup locations; and usage with high concrete grade for effective exploitation.

THE EFFECT OF COLD DEFORMATION AND ANNEALING PHENOMENA ON THE MICROSTRUCTURAL CHANGES AND MICRO-HARDNESS IN Al-Mg-Si ALUMINIUM ALLOYS

Aluminium alloys are of particular interest because of their low density, low cost and ease of thermo-mechanical processing. During the recent years, much interest has been shown in the development of alloys with optimal mechanical properties which can be retained at high temperatures. The purpose of the present investigation is to study the microstructure of two Al-Mg-Si alloys containing transition elements after cold deformation 10%, 20 %, 30%, 40% and 50% reduction in thickness and annealing at 1 hour at different temperature by using the optical microscopy, transmission electron microscopic (TEM), Vickers hardness measurement. We notice that the micro-hardness increases with the increasing of the deformation level. The coarse particles, with a particle size of about 2 to 3 µm, give rise to a heavily local deformation of the Aluminium matrix. The formation of well-defined substructure due to the arrangement of dislocations is observed after an increase in annealing temperature.

Geodetic deformation forecasting based on multi-variable grey prediction model and regression model

Purpose The purpose of this paper is to examine the effectiveness of the multivariable grey prediction model in deformation forecasting. Design/methodology/approach Deformation in a dam can be seen because of many factors but without any doubt, the most influential factor is the water level. In this study, the deformation level of a point in the Keban Dam crest has been tried to be forecasted depending on the water level by the multivariable grey model GM(1,N). Regression analysis was used to test the accuracy of the prediction results obtained using the grey prediction model. Findings The results show that there is a great consistency between the grey prediction values and the actual values, and that the GM(1,N) produces more reliable results than the regression analysis. Based on the results, it can be concluded that the GM(1,N) is a very reliable estimation model for limited data conditions. Originality/value Different from the other studies in the literature, this study investigates deformation in a dam subject to the water level in the dam reservoir. The main contribution of the study to the literature is to suggest a relatively new procedure for estimating the deformation in the dams based on the water level.

Design, Development and Numerical Experiments of Compliant Anchor Mechanism for Clamping Purpose - A Topology Optimization Method

In the present scenario, every industry focusses mainly on the reduction of wastes. Because waste or scrap plays a major part in the economic status of an industry. It also involves the wastage of time, man power, machine power, raw material, electricity etc.Compliant Anchor mechanism is a flexible mechanism that transfer an input force and displacement at one part to an output force and displacement at another part through elastic body deformation. These may be monolithic (single-piece) or joint less structures.This paper elucidates a Compliant mechanism-based part i.e. Compliant Anchor is designed and numerically analyzed for its mobility, strength and durability with various material characteristics. This Compliant Anchorstructure is designed and developed as such Rigid bodiesapplication. Compliant Anchor is précised and exhibits Larger displacement at its wings with smaller strain.In this work the Compliant Anchor is suitably designed based on rectangular slot hole domain in a work piece to clamp the work piece rigidly(Casesapplication)in its surface, For that purpose various material characteristics chosen for design and development, The deformation study of the compliant anchor with various material characteristics analyzed through numerical analysis and The final topology optimized design is taken for development in 3D printing technology, This design can be used for various clamping applications suitably based on deformation level and application of external force.

Analysis of Electric Power Quantities of Road LED Luminaires under Sinusoidal and Non-Sinusoidal Conditions

The paper presents the results of laboratory tests concerning the measurements of electrical parameters of road lighting luminaires. These measurements were focused on determining the dependence of the electrical parameters of the luminaires versus the changes of the RMS (Root Mean Square) value of the supply voltage and the level of disturbances in the supply voltage. The basic electrical parameters for light-emitting diode (LED) luminaires were analysed with the option of luminous flux adjustment if it existed. During the laboratory measurements, the luminaires were powered from the Agilent 6834B distorted voltage generator within the assumed acceptable range of the changes in the deformation level resulting from the applicable legal provisions for the reproduction of actual power supply conditions.

Microstructure Evolution and Mechanical Stability of Retained Austenite in Thermomechanically Processed Medium-Mn Steel

A microstructure evolution of the thermomechanically processed 3Mn-1.5Al type steel and mechanical stability of retained austenite were investigated during interrupted tensile tests. The microstructural details were revealed using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) techniques. It was found that the strain-induced martensitic transformation began in central regions of the largest blocky-type grains of retained austenite and propagated to outer areas of the grains as the deformation level increased. At rupture, the mechanical stability showed only boundaries of fine blocky grains of γ phase and austenitic layers located between bainitic ferrite laths. The effects of various carbon enrichment, grain size, and location in the microstructure were considered. The martensitic transformation progress was the highest at the initial stage of deformation and gradually decreased as the deformation level increased.