En
  • دکتری (1392)

    مهندسی مکانیک - ساخت و تولید

    دانشگاه تهران، تهران، ایران

  • کارشناسی‌ارشد (1385)

    مهندسی مکانیک-ساخت و تولید

    دانشگاه صنعتی امیر کبیر، تهران، ایران

  • کارشناسی (1382)

    مهندسی مکانیک-ساخت و تولید

    دانشگاه علم و صنعت ایران، تهران، ایران

  • جوشکاری
  • مدلسازی ‌فرآیندجوشکاری
  • آزمونهای غیر مخرب
  • روشهای نوین عیب یابی

    دکتری مهندسی مکانیک-ساخت و تولید از دانشگاه تهران 1392 کارشناسی ارشد مهندسی مکانیک-ساخت و تولید از دانشگاه صنعتی امیرکبیر 1385 کارشناسی مهندسی مکانیک-ساخت و تولید از دانشگاه علم و صنعت ایران 1382

    ارتباط

    رزومه

    Evaluation of the defects in the underload polymers using shearography method by thermal excitation

    E Aghajafari, D Akbari
    Journal Papers , , {Pages }

    Abstract

    Non-destructive evaluation of internal cracks in GFRP using digital shearing interferometry

    Farzad Banakar, Davood Akbari
    Journal PapersAmirkabir Journal of Mechanical Engineering , 2021 March 14, {Pages }

    Abstract

    Shearography is one of the recent methods of non-destructive technique based on the interference of laser beams that have been reflected from the surface of the specimen. This method, which has high speed and accuracy, can evaluate the displacement derivative on the sample surface at once. In this paper, the possibility of sub-surface cracks detection with different lengths and angles in composite samples was investigated by shearography method and thermal stimulation system. For this purpose, in composite samples, manufactured and controlled cracks were created with different lengths and angles. After calibration of the performance of the shearography setup, two heat sources of radiation were used to load samples. Loading quantity, the amo

    Assessment of Delamination Growth due to Matrix Cracking in Hybrid Glass-Kevlar Composite Laminates Using Experimental, Numerical and Analytical Methods

    Amin Farrokhabadi, Sara Neyestani, Davood Akbari, Reza Sarkhosh
    Journal PapersEngineering Fracture Mechanics , 2021 March 18, {Pages 107691 }

    Abstract

    In this study, the growth of induced delamination in off axes composite laminates has been investigated. Glass-Epoxy composite laminates and Glass-Kevlar-Epoxy hybrid composite laminates with cross-ply [04/90n]s and angle-ply [304/90n]s and [454/90n]s composite layup, containing a low density matrix crack in 90? layers have been made. Then they have been subjected to tensile loading in experimental tests in order to investigate the growth delamination from the location of the matrix cracking and to measure the stiffness degradation. The experimental observations reflect the effects of hybridization and staking sequences on the induced delamination growth for the first time. In addition, the growth of delamination in the considered composite

    Non-destructive evaluation of internal cracks in glass fiber-reinforced polymers using digital shearing interferometry

    F Banakar, D Akbari
    Journal Papers , , {Pages }

    Abstract

    Non-destructive measurement of internal defects using shear laser interferometry method

    FARSHI SINA SABBAGHI, DAVOOD AKBARI, Nasrabad Navid Saberi
    Journal Papers , Volume 7 , Issue 100900, 2020 January 1, {Pages 45-52 }

    Abstract

    Digital shearography is a laser interferometry method that is used to detect and measure defects non-destructively. In this study, a new approach was presented to measure internal planar defects using digital shearography method. A total of 16 shearography tests were carried out in order to verify the proposed method and study the effect of shear size and depth of defect on measurement accuracy. Defect size was varied in four level and depth of defect and shear size were changed in two levels. The defects size were measured in different conditions and the estimation error was obtained in each case. The proposed method was able to predict defect size with good precision and the lowest error percentage was obtained in 15 mm size 0. 5 mm depth

    Nondestructive Evaluation of Gas Turbine Blade Cooling Holes Blockage by Thermography

    Ali Mohammad Kolagar, Mohammad Cheraghzadeh, Davood Akbari, Mohammadreza Farahani
    Journal PapersNDT Technology , Volume 2 , Issue 6, 2020 August 22, {Pages 46-52 }

    Abstract

    Turbine blades are one of the most sensitive and important hot parts of gas turbines, so that the efficiency and life of turbines are directly related to the operation of these components. Therefore, to prevent damage caused by high temperatures, they must be properly cooled. The common method of cooling these parts is to pass the cooling fluid through their complex internal channels. Non-destructive testing of thermography, is one of the new methods for detecting imperfections in these cooling paths which is considered in this article. Thermal loading is applied in an active manner by hot steam generator system. In order to identify the capability of this system in the detection of the residuals in the cooling system of blades, 3 kinds of

    Investigation on the effects of the joint type on the driven out bead in the welded pipes produced by high-frequency induction welding

    M Ghaffarpour, D Akbari, H Moslemi Naeini
    Journal PapersProceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications , 2020 November 17, {Pages 1.46E+15 }

    Abstract

    In this paper, the effects of the joint type on the driven-out bead of the roll-formed pipes, welded by high-frequency induction welding process are studied. The main goal is to predict and reduce the volume of the bead driven out in the weld seam. Moreover, it aims to move the semi-solid bead during welding to the outer diameter of the pipe. This study has two prior aims: to produce a defect-free joint and to improve the mechanical and metallurgical properties. In order to optimize the weld joint, various joint types have been investigated by experimental tests and simulation. Lastly, destructive tests were used to determine if the desired mechanical properties of the weld joint were obtained. The metallurgical properties and the derivatio

    Application of vibration loading method for non-destructive testing of polymer Material by Means of Laser Shear Interferometry

    N Saberi NasrAbad, D Akbari, MR Karafi
    Journal PapersJournal of Solid and Fluid Mechanics , Volume 10 , Issue 4, 2020 December 21, {Pages 15-26 }

    Abstract

    In this paper, shearography or speckle pattern shearing interferometry, which is one of the moders optical and non-contact methods in non-destructive testings (NDT) of materials, is investigated. To this purpose, the workpeace should be subjected to a kind of loading. Some of the conventional loading methods in are relative vacuum loading, thermal loading, and Acoustic Loading. In this paper, The Acoustic loading method has been developed to stimulate and identify the defects. Two methods of thermal loading and Acoustic loading were compared on polyethylene and Teflon pieces with Delamination created behind them, thereafter, The effect of the type of loading on the capability to identify defects, as well as the quality of scanning results,

    Ultrasonic welding of thermoset matrix composites reinforced with glass fibers using a co-cured retaining layer

    A JabariRad, D Akbari, M Golzar
    Journal PapersJournal of Welding Science and Technology of Iran , Volume 6 , Issue 2, 2020 December 10, {Pages 137-144 }

    Abstract

    In this paper, ultrasonic welding of glass fiber reinforced thermoses, co-cured whit a thermoplastic has been studied. Co-curing process forms a connection between the thermoset and the thermoplastic while curing the composite. Considering that the calculated stress should not be related to the dimensions of the sample, a horn with a tip dimension smaller than the standard overlap was used. The results show that the actual weld dimensions are bigger than the intended weld dimensions. This has happened due to the movement of the melted thermoplastic to the sideways during the welding. The design of experiment has been done using response surface central composite, and a quadratic equation based on the lap shear strength of the welds containi

    A Review on Non-Destructive Identification of Defects in Fiber Reinforced Polymeric Base Composites

    Soheil Mirzaahmadi, Davood Akbari
    Journal PapersNDT Technology , Volume 2 , Issue 5, 2020 February 20, {Pages 14-29 }

    Abstract

    In recent years, limitations such as the inability to inspect composite materials in common non-destructive testing methods (NDT) have led to the development of new methods such as optical thermography (OPT) and digital shearography (DISH) which are able to resolve these limitations with non-contact and full field inspection. The aim of this paper is to compare the new and traditional NDT methods and also to mention the main features of these new methods such as detection of the defects by stimulating the specimen and receiving its response as out-of-plane displacement derivative (strain) and temperature gradients. The results show that the loading conditions, type of inspected defects, shear amount and the studied material are effective pa

    Non-destructive measurement of internal defects using shear laser interferometry method

    Sina Sabbaghi Farshi, Davood Akbari, Navid Saberi Nasrabad
    Journal PapersIranian Journal of Manufacturing Engineering , Volume 7 , Issue 1, 2020 March 20, {Pages 45-52 }

    Abstract

    Digital shearography is a laser interferometry method that is used to detect and measure defects non-destructively. In this study, a new approach was presented to measure planar defects using digital shearography method. A total of 16 shearography tests were carried out in order to verify the proposed method and study the effect of shear size and depth of defect on measurement accuracy. Defect size was varied in four level and depth of defect and shear size were changed in two levels. The defects size were measured in different conditions and the estimation error was obtained in each case. The proposed method was able to predict defect size with good precision and the lowest error percentage was obtained in 15 mm size 0.5 mm depth defect at

    The influences of the cyclic force magnitude and frequency on the effectiveness of the vibratory stress relief process on a butt welded connection

    SM Ebrahimi, M Farahani, D Akbari
    Journal PapersThe International Journal of Advanced Manufacturing Technology , Volume 102 , Issue 08-May, 2019 June 19, {Pages 2147-2158 }

    Abstract

    Welding residual stresses are considered as significant factors for the reduction of fatigue life and load bearing of welded structures. In this article, characterization of a low-temperature stress-relief method called vibratory stress relief process was investigated. In this regard, welding of a butt joint of two steel plates was simulated and induced welding residual stresses were calculated. An experimental residual stress measurement was conducted to verify the numerical results. It was established that the simulated residual stresses are in good agreement with the measured results obtained from the hole drilling strain gauge measurements. In the following, the vibratory stress relief process of the welded joint was simula

    Effect of forming parameters on edge wrinkling in cold roll forming of wide profiles

    H Mohammdi Najafabadi, H Moslemi Naeini, R Safdarian, MM Kasaei, D Akbari, B Abbaszadeh
    Journal PapersThe International Journal of Advanced Manufacturing Technology , Volume 101 , Issue 04-Jan, 2019 March 17, {Pages 181-194 }

    Abstract

    The cold roll forming is a continuous metal forming process to produce a large variety of profiles. A major product of the cold roll forming is wide profiles whose application is expanding in the construction of houses, bridges, airports, sports arenas, etc. The edge wrinkling is one of the common defects in the cold roll forming of the wide profiles. The edge wrinkling leads to several problems, such as decrease of dimensional tolerances, abrasion of forming rolls due to contact with the wrinkled edge, non-uniform distribution of forming through the production line, and unsuitable energy consumption. In this paper, the mechanics of edge wrinkling in the cold roll forming of the wide profile is investigated, and the effect of

    Experimental and numerical investigation of the effects of the pre-heating in the modification of residual stresses in the repair welding process

    M Charkhi, D Akbari
    Journal PapersInternational Journal of Pressure Vessels and Piping , Volume 171 , 2019 March 1, {Pages 79-91 }

    Abstract

    In this paper, the application of pre-heating process on the reduction of residual stress in the repair welding of steel pipes is investigated. In this purpose, a thermo-elastic-plastic molding of the repair welding process is developed using finite element method. In order to verify this modeling method, experimental data of repair welds of a carbon steel pipe, measured by deep hole drilling method, were utilized. The verified results indicated that the developed computational method can be beneficially used as an effective tool to predict the residual stress of the pipes undergo the repair welding. The verified finite element model was utilized in the repair welding of carbon steel and stainless steel pipes to consider the effects of preh

    Friction Stir Weld of AZ91 Magnesium Alloy With and Without Nano-SiC Particle

    M Farzami, M Farahani, D Akbari, M Tabasi
    Journal PapersJOM , Volume 71 , Issue 11, 2019 November 1, {Pages 4171-4179 }

    Abstract

    In this article, the influence of SiC nanoparticles on the friction stir welding of AZ91 magnesium alloy has been studied. For this purpose, a groove was designed to incorporate the nanoparticles into the weldment without requiring any additional tool to cover the weld surface. The welding process was carried out with and without nanoparticles in different process conditions. The mechanical properties and microstructure of the prepared joints were also studied. The results indicated that without using the nanoparticles, the minimum grain size of 2.79??m along with the strength of 99% of the base metal can be achieved by applying the highest examined welding traverse speed and the lowest rotational speed. By using the SiC nano

    Improvement of the joint quality in the high-frequency induction welding of pipes by edge modification

    Morteza Ghaffarpour, Davood Akbari, Hasan Moslemi Naeeni, Sajad Ghanbari
    Journal PapersWelding in the World , Volume 63 , Issue 6, 2019 November 1, {Pages 1561-1572 }

    Abstract

    High-frequency induction welding (HFIW) is among the most commonly used methods for producing roll formed pipes. In this paper, weld quality is evaluated through examining the weld properties, in order to obtain the effect of edge preparation on improvement of weld quality. Temperature distribution in the weld zone is studied through the groove shape of the weld joint, and the other parameters such as current, frequency, and linear speed, considered constant, are equal to 1400?A, 150?kHz, and 25?m/min respectively. The mechanical and metallurgical properties of the weld metal were evaluated by tensile test and metallography. The appropriate temperature distribution resulted from modifying the shape of the connecting edges, le

    Application of pre-heating in the reduction of distortion in the dissimilar joints welding SS type 304 and carbon steel A106-B

    MEHRAN CHARKHI, GHOLAMREZA FAGHANI, DAVOOD AKBARI, Maghsoud Shalvandi
    Journal Papers , Volume 6 , Issue 600852, 2019 January 1, {Pages 51-63 }

    Abstract

    In this paper, thermo-mechanical behavior of the welding process was analyzed to determine the effect of preheating on the distortion magnitude and distribution in dissimilar joints. By using a verified finite element model, an efficient user subroutine was developed to consider the effects of phase transformation. In order to verify the model, experimental data for dissimilar joints, obtained by CMM measuring device method, were utilized. Good agreement was observed between the finite element and experimental data. The results indicated that the developed computational method is an effective tool to predict the distortion of dissimilar weld joints. The present finite element model was developed in a butt-welded plate to consider the effect

    Geometry Effects of Asymmetrical Channel Sections on Common Defects in the Roll Forming Process

    NAEINI H MOSLEMI, TAFTI R AZIZI, D AKBARI, MM KASAEI
    Journal Papers , Volume 30 , Issue 22000897, 2019 January 1, {Pages 16-Jan }

    Abstract

    In this research, the twist and the longitudinal bow defects were studied by finite element analysis in the asymmetrical channel sections. Effects of the geometrical properties including the strip thickness, the web width, and the flange width were investigated on the above effects. Some experiments were performed on an industrial roll-forming machine to verify the accuracy of the finite element model. The results showed that the twist angle decreases with the increase of both strip thickness and web width. However, the twist angle increases with the increase of flanges width. Also the variations of the longitudinal bow height are similar to those of the average residual longitudinal strain of both flange edges.

    Non-destructive residual stress measurement using digital image correlation method

    Peyman Ghasemi Tamami, Davood Akbari, Farid Azadi
    Journal PapersNDT Technology , Volume 2 , Issue 3, 2019 February 20, {Pages 50-58 }

    Abstract

    In this paper, we examine the method of Digital Image Correlation (DIC) and introduce a new theory for measuring residual stresses in non-destructive mechanical parts. In this regard, with the aim of scientific proof, the new theory introduced into the review of the article related to the idea presented in this study and its details have been discussed. First, the principles of the method of digital image correlation and methods for calculating correlation coefficients are presented. With the aim of evaluating the authenticity of the outputs of digital imaging, by constructing the required equipment and performing empirical tests to perform the process, comparing the output results of the digital imaging overlap method and the finite elemen

    Application of laser shearing interferometry in non-destructive inspection and size estimation of plane defects

    S Sabbaghi Farshi, D Akbari
    Journal PapersJournal of Solid and Fluid Mechanics , Volume 9 , Issue 4, 2019 December 22, {Pages 14-Jan }

    Abstract

    Laser shear interferometry or shearography is one of the novel NDE methods that is used to inspect and estimate the size of subsurface defects. In this research, a new method for estimating the size of plane defects was presented. In order to verify and compare the proposed method with conventional methods and studying the effect of defect depth and shear size on the accuracy of the measurements, different plane defects were tested. The size of the defects was measured in different conditions and the estimation error was reached in each case. Also, Finite element simulation was used to study the effect of loading time estimation error. The results showed that the proposed method was able to predict the defect more accurately than the conven

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    دروس نیمسال جاری

    • كارشناسي ارشد
      آزمون غير مخرب پيشرفته ( واحد)
      دانشکده مهندسی مکانیک، گروه مهندسي ساخت و توليد
    • كارشناسي ارشد
      آزمون غير مخرب پيشرفته ( واحد)

    دروس نیمسال قبل

    • كارشناسي ارشد
      متالوژي در توليد ( واحد)
      دانشکده مهندسی مکانیک، گروه مهندسي ساخت و توليد
    • دكتري
      متالوژي در توليد ( واحد)
    • 1400
      مقيمي, علي
      بررسي اثر تنش زدايي ارتعاشي و ارتعاشي-حرارتي در اتصالات جوشكاري شده
    • 1397
      ميرزااحمدي, سهيل
      جوش فراصوتي كامپوزيتهاي گرماسخت با افزودن نانو ذرات و با استفاده از روش آماده سازي سطح
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