• فهرست مقالات Shear strength

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        1 - An Experimental Investigation on Comparison of the Similar and Dissimilar Resistance Spot Welding of St12 and Galvanized Steel using Design of Experiments
        Mahmoud Moradi Hadi Abdollahi Ali Khorram
        In the present research, similar and dissimilar resistance spot welding (RSW) process of St12 and galvanized steel sheets with thickness of 0.9 mm was investigated. The experiments were carried out based on the statistical design of experiments (DOE) approach to investi چکیده کامل
        In the present research, similar and dissimilar resistance spot welding (RSW) process of St12 and galvanized steel sheets with thickness of 0.9 mm was investigated. The experiments were carried out based on the statistical design of experiments (DOE) approach to investigate the effect of RSW parameters on the welding quality, achieving the mathematical regression equations and predicting the new results. Welding time and electrode force were considered as the input process variables while the tensile-shear strength of the joints was considered as the process response. By comparing three RSW types, galvanized steel has the highest tensile-shear strength. Statistical analysis shows that tensile-shear strength is increased with increasing electrode force and welding time. Verification experiments for three types of RSW joints were carried out in order to analyse the obtained results via software. Good agreement between the verification tests and the optimization results revealed that the statistical modelling would be appropriate for RSW process. Welding time (T)  = 5 s and electrode force (P)  = 925 N, welding time (T) = 5 s and electrode force (P) = 1100 N and welding time (T) = 3 s and electrode force (P) = 925 N were obtained as the optimum settings for similar RSW of St12, dissimilar RSW of St12 to galvanized steel and similar RSW of galvanized steel, respectively. پرونده مقاله
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        2 - Geological and engineering geological characteristics of surface alluviums in the Gorgan city
        Rasool Yazarloo ماشالله خامه چیان محمدرضا نیکودل
        10.30495/ijes.2022.690880
        Engineering properties of soils and the 3D modeling of geological formations are widely used in site investigations and the preparation of geological hazard maps. The present study was conducted to characterize the engineering geological properties of the young surface چکیده کامل
        Engineering properties of soils and the 3D modeling of geological formations are widely used in site investigations and the preparation of geological hazard maps. The present study was conducted to characterize the engineering geological properties of the young surface alluviums of the Gorgan city (Iran) to a depth of 25 m and 3D modeling of their geology using boreholes data. To this end, after determining the location of the available boreholes on the aerial map of Gorgan, four hypothetical cross-sections were considered in the North-South and East-West directions. Then, the borehole data were marked on each section and their 2D geological cross-sections were manually drawn using correlation of the similar layers. In the next step, by expanding the information of these sections, a 3D geological model of Gorgan city was prepared using a conceptual-observational method. According to the evidence from the boreholes and field observations, the depositional environment of Gorgan alluviums was an alluvial fan created by the Ziarat River. Additionally, in terms of engineering characteristics of alluviums, the Gorgan subsurface soils can be divided into four engineering units, including upper clay unit (UCU), middle gravel unit (MGU), lower clay unit (LCU), and sandy unit (SU), which share the same engineering characteristics. Finally, the results of tests performed on samples from different depths were employed to calculate the engineering geological characteristics of each unit, including Atterberg limits, compressibility, undrained shear strength, and drained shear strength parameters. پرونده مقاله
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        3 - Experimental Study on the Effect of Crumb Rubber on Shear Strength of Sandy Soil
        Soheil Ghareh Seyed Vahid Mojtahed Sistani
        Nowadays, soil reinforcement using polymer elements have been investigated by a number of researchers in order to increase the load capacity of soils. Reinforcing soils using fibers is a method of soil improvement, which offers a homogenous mixture in combination with s چکیده کامل
        Nowadays, soil reinforcement using polymer elements have been investigated by a number of researchers in order to increase the load capacity of soils. Reinforcing soils using fibers is a method of soil improvement, which offers a homogenous mixture in combination with soils, regarding their tensile strength. This combination maintains pressure loading capacity and properties in mutual resistant tensile. The present research investigates the effect of crumb rubber bearing the size of 5mm × 5mm and 10%, 25% and 40% volume on sandy soil behavior using large-scale direct shear test (300mm × 300mm × 150mm) under the vertical stresses of 50, 100 and 150kPa. Results showed that the optimum volume percentage of crumb rubber for maximum shear strength is between 20% and 25%. پرونده مقاله
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        4 - Dissimilar resistance spot welding of AISI 1075 eutectoid steel to AISI 201 stainless steel
        Mehdi Safari Hossein Mostaan
        In this paper, dissimilar resistance spot welding of AISI 1075 eutectoid steel to AISI 201 stainless steel is investigated experimentally. For this purpose, the experiments are designed using response surface methodology and based on four-factor, five-level central comp چکیده کامل
        In this paper, dissimilar resistance spot welding of AISI 1075 eutectoid steel to AISI 201 stainless steel is investigated experimentally. For this purpose, the experiments are designed using response surface methodology and based on four-factor, five-level central composite design. The effects of process parameters such as welding current, welding time, cooling time and electrode force are investigated on the tensile-shear strength of resistance spot welds. The results show that tensile-shear strength of spot welds is increased with increase in the welding current and welding time. Also, it is concluded from results that with increasing the electrode force and cooling time, tensile-shear strength of welded joints is decreased. During tensile-shear tests, three failure modes are observed, namely interfacial, partial pullout and pullout modes. The analysis of variance for the tensile-shear strength indicates that the main effects of welding current, electrode force, welding time, cooling time, second- order effect of the welding current and cooling time, two level interactions of welding current with welding time, welding current with cooling time and electrode force with cooling time are significant model terms. The results of analysis of variance show that the presented model for tensile-shear strength of dissimilar resistance spot welds of AISI 1075 eutectoid steel to AISI 201 stainless steel can predict 95.00% of the experimental data and leave only 5.00% of the total variations as unexplained. پرونده مقاله
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        5 - Effect of silver interlayer on transient liquid phase (TLP) bonding of Al2024 to Ti-6Al-4V joints
        Mohammad Ammar Mofid Hamid Naeimian Mostafa Hajian Heidary Mohmood Farshbaf
        Transient liquid phase (TLP) bonding of two dissimilar alloys Al 2024 and Ti-6Al-4V was carried out at 580 and 600 °C for 45 min bonding time using a 30-µm-thick pure silver (Ag) foil interlayer. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) w چکیده کامل
        Transient liquid phase (TLP) bonding of two dissimilar alloys Al 2024 and Ti-6Al-4V was carried out at 580 and 600 °C for 45 min bonding time using a 30-µm-thick pure silver (Ag) foil interlayer. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the phase structure and compositional changes across the joint region. Mechanical properties of the joints were investigated through shear strength and hardness tests. The joint formation was due to the solid-state diffusion of Ag and Cu into Al and Ti alloys, followed by eutectic formation, isothermal solidification, and formation of various intermetallic compounds such as Ag2Al, Al2Cu and Al2CuMg along the Ag/Al2024 interface. Moreover, the interdiffusion of titanium and aluminum led to the formation of Al3Ti intermetallic compounds. These types of intermetallics produced a metallurgical bond at Al 2024 interface. The study showed that the shear strength of the joint reaches a high value of 176.11 MPa obtained at the higher bonding temperature of 600 °C. It was also observed that the sample failed away from the base metal. پرونده مقاله
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        6 - Investigation of Mechanical Properties for Commercial Purity Titanium Severely Plastic Deformed by Accumulative Roll-bonding Process
        Pooya Bahrami Abdolhamid Azizi
        In this study accumulative roll bonding (ARB) process up to 8 Cycles (equivalent strain of 6.4) at ambient temperature was used in order to improve the mechanical properties of Commercial purity titanium (CP-Ti).Several experiment has been done and Mechanical properties چکیده کامل
        In this study accumulative roll bonding (ARB) process up to 8 Cycles (equivalent strain of 6.4) at ambient temperature was used in order to improve the mechanical properties of Commercial purity titanium (CP-Ti).Several experiment has been done and Mechanical properties of specimen has been discussed. For investigating optical microscope punching and hardness test were utilized. This is the first study on shear strength of CP-Ti formed by the ARB process. In this study Yield Shear Strength (YSS), Ultimate Shear Strength (USS), elongation, punching energy and hardness were investigated. Results of experiment report that as the number of the ARB process increased, the shear strength increased but after that certain cycle YSS and USS gradually decreased. As well as increasing numbers of ARB cycles, elongation decreased. Result reported that the shear strength of specimen reached to maximum value at certain cycle and afterward due to grain recovery and specimen fracture, it decreased. Experiments indicate that maximum hardness’s and shear strength were obtained in cycle 4 and 6respectively. Furthermore specimen fracture after 8 cycles ARB processing was observed. پرونده مقاله
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        7 - تحلیل عددی عملکرد قاب‌های مهاربند‌های واگرای مجهز به ورق فولادی در ناحیه تحتاتی تیر پیوند و تیر خارج از پیوند
        حمید ستاریان کرج آباد احمد ملکی
        کشور ایران بدلیل وجود گسل‌های متعدد و اعمال تنش توسط صفحات پوسته مرزی، همواره شاهد رخداد زلزله‌های متعددی در طول سال می‌باشد. بنابراین ارائه‌ی سیستم‌های مقاوم برای پایداری سازه‌ها در برابر نیروهای جانبی از دغدغه‌های اصلی مهندسی عمران در کشور می‌باشد. از سیستم‌های مقاوم چکیده کامل
        کشور ایران بدلیل وجود گسل‌های متعدد و اعمال تنش توسط صفحات پوسته مرزی، همواره شاهد رخداد زلزله‌های متعددی در طول سال می‌باشد. بنابراین ارائه‌ی سیستم‌های مقاوم برای پایداری سازه‌ها در برابر نیروهای جانبی از دغدغه‌های اصلی مهندسی عمران در کشور می‌باشد. از سیستم‌های مقاوم جانبی، مدل قاب مهاربند واگرا می‌باشد که با تکیه بر دوران تیر پیوند باعث جذب نیروی زلزله در سازه می‌شود، در‌حالیکه دوران بیش از حد در ناحیه تیر پیوند می‌تواند سطح عملکرد سازه را دچار ضعف گرداند و باعث تشکیل ترک‌هایی قابل توجه در دال بتنی گردد. در تحقیق حاضر مدل نوینی از سیستم مهاربند واگرای مجهز به ورق فولادی در ناحیه تحتانی تیر پیوند و تیر خارج از پیوند ارائه شده است. مدلسازی عددی در نرم‌افزار آباکوس و پروتکل بارگذاری بر مبنای ATC-24 اعمال گردیده است. نتایج حاصل نشان می‌دهد مکانیابی بهینه ورق‌های فولادی و اعمال آن‌ها در ناحیه تحتانی تیر و تیر خارج از پیوند باعث بهبود عملکرد برشی سیستم مهاربندی در تشکیل مفاصل پلاستیک و افزایش مقاومت برشی و شکل‌پذیری مدل مهاربندی می‌گردد. در نهایت میزان جذب انرژی توسط مدل‌ها در مقایسه با مدل رایج دارای عملکرد مطلوب قابل توجهی می‌باشد. پرونده مقاله
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        8 - Evaluation of the Mechanical Strength of Gerbera Flower Stem in Response to Silicon and Salicylic Acid Application
        Mesbah Babalar Behzad Edrisi Roohangiz Naderi
        Stem and peduncle bending by the weight of the flower is one of the main postharvest problems in gerbera (Gerbera jamesonii Bolus.) and sometimes caused stem crushing or water loss. In this research, silicon and salicylic acid were applied to enhance the mechanical stre چکیده کامل
        Stem and peduncle bending by the weight of the flower is one of the main postharvest problems in gerbera (Gerbera jamesonii Bolus.) and sometimes caused stem crushing or water loss. In this research, silicon and salicylic acid were applied to enhance the mechanical strength of inflorescence stem, and the results revealed that stem curving was decreased by silicon and salicylic acid treatments. Shear strength and lignin content were increased by SA treatments at both upper and lower parts of the stem. It seems that lignin content was associated with shear strength at upper part of stem. Additionally, silicon content of flower stem was significantly increased under silicon application and mechanical strength of the lower part of stem has correlation with silicon content in stem tissue. These results suggested that silicon and salicylic acid application could enhance the mechanical strength of inflorescence stem and improve the cut flower quality in gerbera. پرونده مقاله
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        9 - Experimental and numerical modeling for shear strength of hybrid fiber reinforced concrete beams with stirrups
        Mahdi Moradi Mehran Sheikhmohammadi Seyyed Hossein Aletaha
        10.1007/ijase.2023.702607
        The use of hybrid fibers in concrete has attracted wide attention in recent years. Using hybrid fibers with different elasticity moduli increases the strength and ductility of fiber reinforced concrete (FRC). In addition, hybrid fibers improve the shear strength of FRC چکیده کامل
        The use of hybrid fibers in concrete has attracted wide attention in recent years. Using hybrid fibers with different elasticity moduli increases the strength and ductility of fiber reinforced concrete (FRC). In addition, hybrid fibers improve the shear strength of FRC beams significantly. The previous studies have shown that the hybrid use of fibers leads to a phenomenon, called synergy. However, the effect of combining hybrid fibers with stirrups is scantly studied and continues to main unknown. In this study, the effects of stirrups, concrete compressive strength, polypropylene fibers, steel fibers, and their hybrids on the shear strength of FRC beams are investigated. For this purpose, 24 FRC beams were tested in an experimental program. Experimental results show that samples with hybrid fiber have the highest shear performance. Additionally, a new model for simulating these beams' shear strength is presented, using genetic programming technique. The proposed model precisely predicts sample performance. The R2 for this model was 0.868, which is a suitable value due to the complexity of the problem. پرونده مقاله
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        10 - Experimental Study of the Nugget Diameter Effect on Tensile-Shear Strength in AISI 1008 Spot Welding Specimens
        A. فدایی ا.ح محمودی آ. برزویی
        The Spot welding is widely used for joining thin sheets in different industries; such as automotive industry. This method of welding is very easy to automate and maintain. In this study, the effect of nugget diameter on the tensile-shear strength of the spot welding joi چکیده کامل
        The Spot welding is widely used for joining thin sheets in different industries; such as automotive industry. This method of welding is very easy to automate and maintain. In this study, the effect of nugget diameter on the tensile-shear strength of the spot welding joints was investigated. The specimens were manufactured from AISI 1008 HR sheets with 1.0 mm thickness. The eight different electrodes with different active face diameters (3mm – 10mm) were employed. Tensile tests of the prepared specimens indicated that both ultimate tensile strength (UTS) and yield stress increased to a certain level and then remained constant. The comparison between specimen failure modes showed that in specimens with lower nugget diameter, tearing occurred in nugget. However with increasing the diameter, failure location moved to nugget edge with tearing in base sheet. Interestingly, the specimens with change in failure location were those that UTS and yield stress were remained almost constant. This was also the case where the elongations of these specimens were studied. پرونده مقاله
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        11 - APPLICATIONS OF PARTIAL DIFFERENTIAL EQUATIONS IN STABILITY INDEX AND CRITICAL LENGTH IN AVALANCHE DYNAMICS
        S. Ahmadi
        In this study, Stability analysis of snow slab which is under detonation has developed in the present model. The model has been studied by using the basic concepts of non-detonation model and concepts of underwater explosions with appropriate modifications to the presen چکیده کامل
        In this study, Stability analysis of snow slab which is under detonation has developed in the present model. The model has been studied by using the basic concepts of non-detonation model and concepts of underwater explosions with appropriate modifications to the present studies. The studies have also been extended to account the effect of critical length variations at the time of detonation and its effects on various material parameters through the concepts of fracture mechanics. The results indicate that the stability and critical length values are lower for the detonation (present) values in comparison with the non-detonated values. The importance of the studies in Avalanche forecasting has been highlighted. پرونده مقاله
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        12 - اتصال نانو کامپوزیت Al-Al3V با استفاده از فرایند اتصال فاز مایع گذرا و ارزیابی خواص آن
        سیده زهرا انوری مهدی رجبی صفورا عشاقی
        در این تحقیق اتصال نانو کامپوزیت زمینه آلومینیومی تقویت شده با ذرات آلومیناید وانادیوم با استفاده از فرآیند اتصال فاز مایع گذرا و ارزیابی خواص آن، مورد بررسی و ارزیابی قرار گرفت. همچنین اثر تغییرات دما و زمان اتصال بر خواص اتصال بررسی شد. برای این منظور ابتدا نانو کامپو چکیده کامل
        در این تحقیق اتصال نانو کامپوزیت زمینه آلومینیومی تقویت شده با ذرات آلومیناید وانادیوم با استفاده از فرآیند اتصال فاز مایع گذرا و ارزیابی خواص آن، مورد بررسی و ارزیابی قرار گرفت. همچنین اثر تغییرات دما و زمان اتصال بر خواص اتصال بررسی شد. برای این منظور ابتدا نانو کامپوزیت Al-Al3V جهت اتصال آماده سازی شد. از فلز مس به عنوان لایه واسطه، استفاده شد و اتصال این قطعات به روش فاز مایع گذرا، در دماهای 560، 580 و 600 درجه سانتی گراد و زمان های 20، 40 و 60 دقیقه مورد بررسی قرار گرفت. جهت ارزیابی ریز ساختار درز اتصال و اطراف آن از میکروسکوپ الکترونی روبشی استفاده شد. همچنین بررسی استحکام برشی اتصال ها توسط دستگاه تست فشار انجام شد. نتایج نشان داد در دمای 580 و 600 درجه‌سانتی‌گراد اتصال بهتری نسبت به بقیه نمونه ها ایجاد شده است. با افزایش دمای اتصال، حجم مذاب ایجاد شده در درز اتصال بیشتر شده و لذا سطح وسیع تری از درز اتصال توسط مذاب پر شد. با توجه به نمودارهای سختی سنجی بدست آمده بیشترین میزان سختی در درز اتصال و اطراف آن در دمای 600 درجه‌سانتی‌گراد در زمان 20 دقیقه است که دلیل آن نفوذ مس و ذرات رسوبی Al2Cu بیشتر در اطراف درز اتصال است. بیشترین استحکام برشی مقدار 65 مگاپاسکال برای اتصال ایجاد شده در دمای 600 درجه‌سانتی‌گراد در زمان 40 دقیقه به دست آمد. پرونده مقاله

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