فهرست مطالب

Engineering - Volume:34 Issue: 10, Oct 2021

International Journal of Engineering
Volume:34 Issue: 10, Oct 2021

  • تاریخ انتشار: 1400/07/04
  • تعداد عناوین: 18
|
  • A. Alvanchi *, N. Didehvar, M. Jalilehvand, P. Adami, S. Shahmir Pages 2198-2205
    Effective marketing is quite vital in many building construction projects that depend on the pre-sale cash in-flow. However, the unsafe condition of the under-construction projects postpones in-person customer visits to the completion date and complicates the marketing process. This safety concern is especially critical for the upper floor units. Although virtual tours of the buildings are used to show the project specifications, they do not convey the impression that customers receive in the real ambiance of in-person visits. This research proposes a novel method called semi-augmented reality to address the safety issue of the under-construction projects during the marketing process. In this method, lower floor apartment units are safeguarded for the customer’s visits to give an accurate impression of the building’s condition. Virtual models of the upper floor apartments are linked to a similar safeguarded unit on the lower floor to augment the existing deviations between lower and upper floor units. The capability of the method was successfully tested in an experimental case. The participating real estate agents in the test found the method beneficial for the customers’ safety, attracting their attention, facilitating the decision-making process, and increasing their convenience. This method introduces a new approach to the building pre-sale marketing process. Similar techniques are expected to emerge shortly.
    Keywords: Augmented reality, Virtual Reality, Building construction, safety, Marketing
  • A.G. Sharanya *, M. Heeralal, T. Thyagaraj Pages 2206-2212
    The goal of this paper is to better understand the shrinkage behavior of low plasticity (CL) soil, which is common in Warangal, India. Understanding the tensile strength and hydro-mechanical response of soil requires an understanding of the contraction behavior of soil caused by drying during wet-dry moisture cycles. With the use of simple and reliable experimental approaches, the shrinkage mechanism and behavior with suction variation are characterized and described in this study. The findings are related to the change in suction, water content, and void ratio of soil that has been air-dried from complete saturation to dryness. The proposed framework uses two simple approaches to understand soil water retention during the drying phase: one to quantify the suction potential and the other to characterize the shrinkage mechanism. In addition, the use of digital image processing (DIP) to capture sample shrinkage using a simple experimental setup is thoroughly discussed. ImageJ software has been found to be feasible for DIP and to quantify the volume change of laboratory samples. The absence of well-structured soil phases or macropores is attributable to the presence of only normal shrinkage and zero shrinkage phases in the tested soil. In terms of water–retention behavior, the shrinkage curve, and the suction curve are very similar. The effects of capillary suction on the shrinkage response of low plastic soil have been observed, emphasizing the importance of characterizing soil shrinkage behavior using suction as a stress-state variable in volume change studies.
    Keywords: Water-retention, low-plasticity soil, shrinkage characterization, unsaturated soil, Digital image analysis, volumetric strain
  • F. Marchione * Pages 2213-2218
    Adhesive joints are becoming increasingly popular in various industrial sectors. However, in spite of numerous recent studies in literature, the design phase of the adhesive joint is still challenging. The main issue in the design phase is the determination of the stress distribution in the adhesive layer under external mechanical loads. In the present study, a classical adhesive joint is analysed in comparison to its modified geometric configuration (i.e. tapered) aimed at reducing the magnitude of stress peaks. In particular, a single-lap joint with steel adherends bonded with a commercial epoxy adhesive is analysed. A 3D FE analysis is conducted to determine the distribution of normal and shear stresses in the mid-plane of the adhesive layer. The results obtained from the present study show that the inclusion of a small taper angle (i.e. 5°) leads to a remarkable reduction of normal stresses (up to 30%) compared to the classical configuration. It is observed that the further increase of the taper angle (up to 15°) does not lead to significant reductions of the stress peaks. The trend in shear stresses, on the other hand, is in contrast: an increase in the taper angle leads to an increase in the shear peaks. The method of tapering the adherends is effective in reducing the normal stresses, which are responsible for triggering the failure in the adhesive joint.
    Keywords: Tensile load, Joint, Steel steel
  • H. Rajabnejad, H. Hamidi *, S.A. Naseri, M.A. Abbaszadeh Pages 2219-2237
    In seismic performance assessment of structures, the features of ground motion (GM) duration on the response of building structures remain vague and have inconclusive results. Also, intensity measures (IMs) link the ground motion hazard with the structural response; hence, using a suitable IM plays a significant role in the prediction of structural response. In this research, the effect of strong ground motion duration and the correlation coefficient of different intensity measures on the residual inter-story drift (RIDR) of a three-dimensional steel structure were investigated. Using nonlinear dynamic analyses and a total number of 34 earthquake records, the relationship between short- and long-duration seismic parameters including amplitude, energy, and frequency content parameters were investigated. The correlation between the 14 selected scalar intensity measures and the RIDR of the structure was also investigated. The results showed the highest correlation between the seismic parameters, such as Peak ground acceleration (PGA), Housner Intensity (HI), and Velocity spectrum intensity (VSI), with other seismic parameters in both short- and long-duration strong ground motions. Based on the maximum residual inter-story drift index, Mehanny and Cordova index (IMC), Bojórquez and Iervolino index (INP), and the geometric mean of Sa (Saave) intensity measures represented the least dispersion versus long-duration records. On the other hand, INP, Spectra acceleration at the period of T1 Sa(T1), and Saave intensity measures showed the least dispersion versus short-duration records.
    Keywords: Intensity Measure, Ground motion duration, Nonlinear dynamic analysis, seismic parameters, Residual inter-story drift (RIDR), Correlation coefficient
  • A. Sepas Hokmabadi *, S . Gholizadeh, S. Tariverdilo Pages 2238-2247

    Reinforced concrete moment resisting frame (RCMRF) is one of the most popular structural systems. Conventionally, buildings with RCMRF systems are designed to satisfy the relative displacement, resistance, and flexibility requirements defined by the design codes. Structural design codes have given different ranges of design parameters that the designers and engineers must consider in the design process of structures and the values selected for these parameters affect the seismic behaviour of the structures. However, performance assessment of the RCMRF under the earthquake loading to limit the probable levels of damage has a complicated and difficult procedure that is time-consuming for designing of ordinary buildings. In this study, to prevent this time-consuming process, tighter ranges for design parameters have been attempted to improve the seismic performance of the RCMRFs. In this regard, databases of RCMFs were created for different ranges of design parameters. The Particle Swarm Optimization (PSO) algorithm is used to create these databases and RCMRFs are optimally designed according to ACI 318-14 code. Then, nonlinear time history analysis according to ASCE/SEI 7-16 code was performed on the RCMRFs in each one of the databases and the statistical analysis of local and global results acquired from the nonlinear time history analysis is carried out. Finally, tighter ranges of design parameters have been determined to achieve more robust structures without involvement in time-consuming processes.

    Keywords: reinforced concrete, Moment-Resisting Frames, optimization, robust design, time history analysis, Non-linear analysis
  • B. Pordel Maragheh, A. Jalali *, S.M. Mirhosseini Pages 2248-2258
    Ignoring the primary damage to structural components due to blast load or fire is the alternate load path (APM) method's weakness in progressive failure analysis. The new technique used in this study examines the structure's more realistic responses by considering the initial cause of the failure. Also, buckling-restrained braces (BRBs) are applied to diminish the potential for progressive failure in braced steel buildings. Variables include the type of primary local loading (APM, blast loading, and heat caused by fire), the position of column removal in the plan (inner and outer frame), the type of brace (BRB and CB), and the number of stories (3, 5, and 8 stories). The buildings were simulated using ABAQUS. The results showed that BRBs in steel buildings under blast load, compared to conventional braces, reduce the potential of progressive failure. The use of BRBs provides much more energy absorption than conventional bracing systems due to brace buckling prevention.
    Keywords: Alternative Load Path Method, Buckling-restrained brace, Finite element method, progressive failure
  • D. Sureshkumar, N. Ethiraj * Pages 2259-2265
    Incremental forming is one of the non-traditional forming processes which is widely used in rapid prototyping and customized component manufacturing. One of the challenges encountered in single stage single point incremental forming (SSSPIF) is difficulty in achieving greater wall angle for a considerable depth. In this research work, the investigation is carried out by experimental and numerical simulation for reaching the maximum wall angle to a possible depth without any defects in SSSPIF. SSSPIF of truncated cone shaped component from 1mm thick AISI304 austenitic stainless steel are made at a different wall angles. Also, numerical simulation using LS-DYNA explicit solver is performed and the results are validated with the experimental values. Components with the wall angle of 64o is successfully without any defects made in a single stage forming for a depth of 45 mm within the experimented process parameters. Major strain, minor strain and thickness distribution in the sheet material due to forming process are obtained from experiments and finite element analysis (FEA). From the results of both experiment and FEA, it is observed that the major strain, minor strain and thinning effects are higher in the region below the major diameter of the truncated cone at all experimented wall angles. Also the FEA results have shown good agreement with the experimental values. Further it is seen that the strains are increasing with the increase of wall angle.
    Keywords: Finite element anlaysis, Single stage incremental forming, Strain measurement, Wall angle
  • M. H. Hoseini, A. Noorzad *, M. Zamanian Pages 2266-2279
    In this study, the mechanical behavior of geosynthetic reinforced soil (GRS) walls has been investigated through physical modeling subjected to strip footing monotonic and cyclic loads at various stress paths. The influence of footing location, stress level, post-cyclic behavior and sand-tire shred admixture on the lateral deformations of the wall facing, bearing capacity and the settlement beneath the footing were assessed. To this aim, 12 physical model tests were conducted with a scale of 1: 4. Results indicated that the bearing capacity has increased with the increase in the offset distance of the strip footing to the wall facing and adding tire shred to the backfill material, but the increase is more prominent by adding tire shred to the backfill material. The location of the footing from the wall facing was a crucial parameter on the deformation of facing and the failure mode of the footing. Failure in the facing was the predominant mode of failure in the near facing footing. However, a rupture in the geosynthetic caused failure in the footing far from facing footing. Also result of cyclic loading tests showed both permanent displacement and residual settlement accumulated with load cycles and a majority of them occurred over the first fifteen cycles. Depending on where strip footing was located, it may or may not induce a magnifying effect on subsequent cyclic loading responses.
    Keywords: geosynthetic reinforced wall, Physical Modeling, Strip footing, tire shred, Bearing Capacity
  • M. Mohsin *, N. Alwash, M. Kadhum Pages 2280-2293
    This paper aims to experimentally investigate and compare the structural behavior of reinforced concrete straight beam and other beams there made with one, two, and three out of plane parts. The study focused on the effect of the number and location of the out plane parts on the beams mid span deflection, and rotation, as well as the ductility index, cracking loads, and failure modes. Four beams were manufactured with a cross-sectional width of 150 mm and a depth of 200 mm, and 2000 mm in length. All the beams were made with normal strength concrete and constant longitudinal reinforcement ratio 0.011 for negative and positive moment. All the beam specimens were clamped by a special steel fixed ends and subjected to the two-point load up to their failure. The obtained results presented that the load bearing capacity of straight beam was higher than the beams with out of plane parts. Furthermore, the beam with two out of plane parts has capacity higher than the beams with one and three out of plane part by 5.86%, and 55.07%. In addition, the results showed that the ductility increased with increasing number of out of plane parts by 5.52%, and 32.71% as copared with the beam with one out of plane part.
    Keywords: Ductility index, cracking loads, Failure modes
  • D. Mibang *, S. Choudhury Pages 2294-2301
    In this study, multiple objectives on earthquake damage assessment procedures have been investigated. The Unified performance-based design (UPBD) method was primarily used to design the Reinforced Concrete (RC) frame shear wall building. The nonlinear dynamic analysis is performed considering spectrum compatible ground motions (SCGM) as per EC-8 demand spectrum at 0.45g level and type B soil condition. It estimated the Damage index (DI) of the building by using Park and Ang method. This method is highly time-consuming as the storey height increases. Hence, it is not suitable for large scale investigation. Therefore, a new approach has been suggested to reduce the computational time and efforts in the case of complex structures to evaluate the global damage index (GDI). In this present study, the most three influencing parameters of the building has been considered to find the global damage index (GDI). And it has also been observed that the most damage occurs on the ground storey of the building compared to the remaining floors. The suggested method efficiently calculates a reliable GDI that can assess building damage from small to large scale.
    Keywords: RC frame shear wall building, Correlation Matrix, EDPs, Damage Evaluation, NLTHA, Global Damage index (GDI)
  • H. Labibi, M. Gerami *, M. Hosseini Pages 2302-2312
    Over years, the energy absorption process against different kinds of loading has always been one the most important issues in the engineering science. To address this, many kinds of dampers such as viscoelastic, friction, yielding, mass, and liquid dampers have been invented. Among all these dampers, steel yielding dampers are one of the most economic, available, suitable, and best choices for the long return period of seismic cyclic loading on structures. However, it seems that there are not sufficient studies on these dampers to convince the designers to use them widely. This research tries to show the effects of geometrical parameters on the energy absorption and cyclic behavior on a specific simple trapezoidal steel yielding damper using the finite element method, then the effect of using a new steel damper on base shear and roof acceleration responses of a three story building studied by nonlinear time history analysis. According to the results, there are some effective and less effective parameters whose variation such as geometrical parameters can seriously change the total energy absorption level and improve the damper hysteresis loops as well as ductility under specific cyclic loading and showed that using new steel damper will results the significant decreasing in base shear and roof acceleration of the building.
    Keywords: seismic behavior, Nonlinear analysis, yielding Damper, Energy dissipation
  • E. Tsigelnyuk, V. Kovalchuk *, V. Gerasimov, E. Efimova Pages 2313-2318
    The article reports on the relevance and the necessity of the introduction of various additives in the composition of grouting mixtures. The analysis of cement compositions with various modifications of carbon is briefly outlined. A method for obtaining fullerene soot and an analysis of its effect on the chemical and physical properties of grouting compositions made of alumina cement is presented. The physical, mechanical and operational properties of the modified grouting mixture are considered. The optimal content of carbon nanoparticles in the binder is 0.1-0.5% BWOC. The introduction of fullerene soot makes it possible to obtain high mechanical properties of cement stone (an increase in uniaxial compression strength by about 15% and a decrease in porosity by about 20%) in comparison with cement mix without additives. It has been determined that using carbon materials is environmentally friendly. The addition of fullerene soot to cement system does not affect the cement hydration processes, provides micro-reinforcement of the cement stone, and prevents the propagation of cracks in it at the nanoscale.
    Keywords: cement, well casing, grouting mixtures, Carbon materials, Fullerene, fullerene soot
  • H. Ahmadi *, M. H. Kadivar Pages 2319-2331
    Seismic vibration of double deck floating roof of Siraf storage tanks located in southern Iran has been studied. Condensate of Nar and Kagan gas field in south of Iran as a very light hydrocarbon, Lavan as light and Soroosh as heavy crude oil content have been chosen. In addition to fluid-structure interaction, intermediate stiffeners, foam seal with nonlinear radial compression behavior and contact friction between the seal and the inner side of the wall are also considered. Under the above conditions, modal and time history analysis has been performed. For time history analysis, Sarpol-e Zahab and Shonbeh earthquakes in Zagros seismotectonic province of Iran and Sakaria as an earthquake near Iran were selected. Dominant natural frequencies, mode shapes of the roof parts and damping ratios of the first and second natural frequencies in addition to overall and spectral behavior of the roof in each liquid cases were obtained and discussed. Changing condensate to Soroosh oil made about 17% hydroelastic natural frequency decrement and about 10% damping ratio decrease for the first natural frequency. The results showed that dominant natural frequencies and the relevant damping ratios decrease with moving from light to heavy liquid. Vibration of the roof fundamentally depends on the frequency content of earthquake in relation to such natural frequencies. Also, floating roof in heavier liquid is more vulnerable to vibration according to the scaling method and steady state amplitude.
    Keywords: Hydroelasticiy, slosh, Foam Seal, Fluid-structure interaction, earthquake
  • S.O Mirabootalebi *, G. H. Akbari, R .Babaheydari Pages 2332-2340

    There are a lot of major parameters in the mechanothermal approach which play a key role in the quality and quantity of the carbon nanotubes (CNTs). In this study, these factors were optimized to maximize the efficiency of the process, and also the growth mechanism of CNTs was investigated. For these purposes, the milling of graphite was performed in a high alloy steel vial for 330 h at the vial speed of 300 rpm in a planetary ball mill. The morphology and crystal structures of the graphite powder during the mechanical activation were studied by x-ray diffraction (XRD), Zeta-Sizer, and scanning electron microscope/energy-dispersive x-ray spectroscopy (SEM/EDX). After the heat treatment of amorphous carbon at 1400 ˚C, the CNTs were synthesized and their quality and quantity were analyzed by transmission electron microscopy (TEM), atomic force microscopy (AFM), XRD, Raman spectroscopy, and differential thermal analysis/thermogravimetric analysis (DTA/TGA). A special type of tip-growth mechanism based on the motion of the catalyst particles was proposed regarding the TEM images. According to this mechanism, the diameter, length, and shape of the CNT are completely dependent on a random motion of the catalyst particle at the tip of the nanotube. As a consequence, the growth mechanism in the mechanothermal process does not follow a certain pattern and this is the main reason for the spring-like and curved shape of the nanotubes. Furthermore, results of the differential thermal analysis revealed that the yield of fabricated multi-walled carbon nanotubes (MWCNTs) is more than 97% of the precursor.

    Keywords: Carbon nanotubes, Multi-walled carbon nanotubes, Synthesis of carbon nanotubes, Growth mechanism of carbon nanotubes, Mechanothermal method, Mass production of carbon nanotubes
  • P. Pasha, H. Nabi, M. Peiravi, M. Pourfallah, D. Damiri Ganji * Pages 2341-2350

    In the present paper, the heat transfer and fluid velocity between two horizontal plates is examined in existence of magnetic parameter. The parameters such as magnetic fluid flow, viscosity, Brownian motion, and thermo-phoretic have been investigated according to this analysis. The innovation of this paper is using two analytical methods for calculate differential equations and comparison these results together. In this paper, the effects of magnetic field on fluid flow for industrial use are investigated. The effects of magnetic field on fluid flow are surveyed by using the Variation Iteration Method (VIM) and the Adomian Decomposition Method (ADM) and compare these methods with the numerical Runge-Kutta method. According to results, increasing the values of the magnetic parameter, the fluid velocity decreased and the fluid viscosity increased. Also, Brownian motion and thermo-phoretic parameters were directly related to the coefficient of friction. The Brownian motion of nanoparticles results in the thermophoresis phenomenon, and increasing both Brownian motion and thermophoresis causes an increase in temperature.

    Keywords: Adomian decomposition method, Brownian motion, Hydrothermal Analysis, Two phase flow, Thermo-phoretic
  • S. Raj, P. Arulraj, N. Anand *, K. Balamurali, G. Gokul Pages 2351-2359
    Global warming is one of the severe environmental effects, faced by the current generation. Studies show that, Carbon di-oxide (CO2) is the major cause for the global warming and is mainly due to huge production of Ordinary Portland Cement (OPC). Supplementary cementitious materials can reduce this effect by reducing the requirement materials instead of OPC for the construction purposes. Geopolymer Concrete (GPC) is a new generation concrete, which does not require OPC. In this study, Fly Ash (FA) was used to produce GPC. Various parameters are considered in the present study. Taguchi’s method is used for analyzing the parameters. An empirical relation is developed to predict the compressive strength of GPC based on the different parameters. Thirty-six mixes were casted to determine the effect of curing temperature, curing time, rest period, ratio of Alkaline Activator solutions (AAs), ratio of activators to FA, molarity of NaOH and replacement level of FA with OPC on the compressive strength. Contribution of each parameter was estimated by ANOVA. Results show that, addition of OPC had a significant effect on the compressive strength of GPC. The mix with 20% OPC, 14M NaOH, curing temperature of 60oC, curing time of 36hrs, rest period of 48hrs, AAs to FA ratio 0.3 and ratio of alkaline solutions 2.5 was found to have the maximum compressive strength. A regression equation is developed to determine the compressive strength of GPC with respect to the parameters considered.
    Keywords: Geo-polymer Concrete, Taguchi method, Compressive strength, Sustainable material
  • E. Taheri * Pages 2360-2370
    Kinodynamic path planning is an open challenge in unmanned autonomous vehicles and is considered an NP-Hard problem. Planning a feasible path for vertical take-off and landing quadrotor (VTOL-Q) from an initial state to a target state in 3D space by considering the environmental constraints such as moving obstacles avoidance and non-holonomic constraints such as hard bounds of VTOL-Q is the key motivation of this study. To this end, let us propose the any-time randomized kinodynamic (ATRK) path-planning algorithm applicable in the VTOL-Q. ATRK path-planning algorithm is based on the Rapidly-exploring random trees (RRT) and consists of three main components: high-level, mid-level, and low-level controller. The high-level controller utilizes a randomized sampling-based approach to generate offspring vertices for rapid exploring and expanding in the configuration space. The mid-level controller uses the any-time method to avoid collision with moving obstacles. The low-level controller with a six-DOF dynamic model accounts for the kinodynamic constraints of VTOL-Q in the randomized offspring vertices to plan a feasible path. Simulation results on three different test-scenario demonstrate the kinodynamic constraints of the VTOL-Q are integrated into the randomized offspring vertices. Also, in presence of moving obstacles, the ATRK re-plans the path in the local area as through an any-time approach.
    Keywords: Kinodynamic path planning, Rapidly-exploring Random Trees, Quadrotor, Collision Avoidance, Dynamic Obstacles
  • A. Ghorbankhan, M. R. Nakhaei * Pages 2371-2378
    Thermoplastic elastomer (TPE) based on polyamid6 (PA6) / acrylonitrile-butadiene rubber (NBR) containing 5% wt nanoclay (Closite 30B) have been prepared via friction stir process (FSP). In this study, the essential work of fracture (EWF) approach was employed to investigate the fracture behavior of PA6/NBR nanocomposites. Also, the modulus strength of specimens was modeled by response surface methodology (RSM), considering three input variables including rotational speed (ω), traverse speed (S), and shoulder temperature (T). Thus, a quadratic mathematical model between input variables (ω, S and T) and response (modulus strength) of PA6/NBR/clay nanocomposites was achieved. Moreover, the morphology of the PA6/NBR blends containing 5% wt was investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that a sample of PA6/NBR thermoplastic elastomer (TPE) containing 5% wt nanoclay at maximum tensile strength exhibited the maximum specific essential work of fracture (we) and specific non-essential work of fracture (wp). Also, the results of the RSM method demonstrate that the optimum condition of the process was found to be at including rotational speed (ω), traverse speed (S), and shoulder temperature (T) of 1200 rpm, 25mm/min, and 146 ℃, respectively. Thus, under the condition optimum, maximum modulus strength of 658 MPa was obtained.
    Keywords: PA6, NBR, Clay, Nanocomposite, Modulus strength, Essential work of fracture, Response Surface Methodology