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In hydroforming process, applying hydraulic pressure to the inner surface of tube along with axial loads to two ends of tube simultaneously cause the tube to be formed to the die shape. Application of finite element simulation is common practice to predict the geometrical dimensions of the produced part and analysis of probable defects. For finite element simulation, precise mechanical properties of tube material are required. Obtaining these properties from a test similar to the tube hydroforming process is desirable. In this study hydraulic bulge test using T-shape die has been introduced to obtain the stress-strain curve of the tube material. Using hydroforming set-up, several experiments were carried out on C12200 copper samples. Geometrical parameters required to be used in analytical solutions have been identified and the stress-strain curve has been plotted. The results of the proposed experiment have been compared to the results of the tensile test. In addition, the effects of anisotropy on the obtained stress-strain curve of both tests have been determined. The stress-strain curve obtained has been used to plot the forming limit diagram. The bulge test mechanical properties and the forming limit diagram have been applied to simulate the tube bursting and prediction of the final part geometrical dimensions in T-shape tube hydroforming and these results have been compared to the part being experimentally produced by hydroforming. The results show that when stress-strain curve obtained by the proposed experiment is used, there is a good agreement between the simulated hydroformed part and the experimental part.

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Due to the increasing demand for using polyethylene pipes in gas distribution networks and regarding the technical specifications of transmission and suitable service condition as well as ease of implementation and installation, these materials are considered as ideal substitutes for metal pipes. Regarding the safety and economic aspects in PE (polyethylene) pipe networks before and during the operations, technical inspection is highly required. Examinations have a significant role in the safety and proper function of gas distribution PE pipes tests, because of the damage of the products and excessive costs and time are not usually affordable. Consequently, the mentioned tests are nowadays being replaced by non-destructive types and admissibility of various industries gas company in these methods is increasing. Electrofusion is a proper and fundamental technique for connecting PE pipes. In this research, the mechanism of electrofusion tapping saddle polyethylene welding has thoroughly been studied and simulated using ABAQUS software. Thermal equation of electrofusion is investigated and the results of simulation as compared with experimental results have been evaluated based on which the best qualified methods for connection have been determined and presented.

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In this paper, the elastic modulus of nanocellulose/PLA nanocomposites obtained by the two methods including nanoindentation and tensile tests were analyzed. Nanocellulose extracted by Mechanical method from linter pulp fiber. Amount of usage of nanocellulose was 3 and 5% wt , as well as for improving of nanoparticles distribution in polymer matrix, masterbatch technique was used. Then the mechanical properties of nanocomposites with and without this technique were studied. Tensile test was performed in accordance with the standard method and for nanoindentation, the atomic force microscope in peak force tapping mode was used. Tensile test results showed that the use of masterbatch, improves tensile modulus, tensile strength and strain at break. Also by increasing nanocellulose percentage from 3 to 5%, in nanocomposite with master batch, the tensile strength and strain at break increased. But this increasing had not significant effect on tensile properties of nanocomposite without masterbatch. A similar trend of strength test results was observed in nanoindentation results. Based on this result, using of masterbatch in nanocomposite caused the increase in elastic modulus. The results of these two analyses were compared and tensile test showed lower modulus value than nanoindentation.

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The main concern in designing of multi-cavity molds is flow balance between cavities. Any departure in flow balancing of the cavities can resulte difficulties in processing and quality of injected parts. In this paper, flow balance in a two-cavity plastic injection mold with different sizes (or called family-cavity mold) was investigated. Moldflow software was implemented to predict the filling phase through the cavities. Diameters of runners related to each cavity were adjusted to attain a balanced flow. Evaluating the flow balance was conducted by injection molding as short-shot and measuring the weight of each cavity. A high density polyethylene (HDPE) was applied as plastic material in this research. Good agreement was observed between experimental and simulation results. Moreover, in this paper one of the runners could be resized while injection molding via an insert located in the mold. The effect of flow balance on the tensile properties of the injection molded specimens was investigated. The results indicated that the parts obtained from the balanced mold exhibit a higher tensile strength and elongation at break up to 14% and 18%, respectively. The dimensions of injected parts were measured. It was found that there are not any differences between the shrinkage of specimens obtained by balanced and unbalanced mold.

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The 5052 aluminum alloy was lap joined to Al-1050 clad steel sheet (with Al-1050 thickness of 1mm) using gas tungsten arc welding (GTAW) process with 4047 Al-Si filler metal at the welding currents of 80, 100 and 120 A. Effect of welding current was studied on the weld microstructure, intermetallic compounds layer and tensile strength of the joints. Microstructural studies were done using optical and scanning electron microscopes (SEM) equipped with energy dispersive spectroscopy (EDS) and tensile strength of the joints was determined by shear-tensile test. Results shows that the reaction layer included two Al3Fe and Al5Fe2 intermetallic phases formed at the interface of the St-12 base sheet and Al-1050 clad layer. Maximum average thickness of the reaction layer was ~3.5 µm .It seems that presence of Al-1050 layer prevents excessive growth of Al-Fe intermetallic layer. The joint tensile strength decreased almost linearly by enhancement of the welding current and the primary α-Al dendrite arm spacing increased and Al-Si eutectics were distributed more uniformly. As a result, the crack easily grows and fracture force reduces. The maximum tensile strength of the joints reached to ~190 MPa, i.e. ~80% of 5052-H34 aluminum base metal strength. During the shear-tensile test, fracture in all the joints was started from the root of the weld and then propagated inside the weld metal with an angle of ~70 with respect to the Al-1050 base sheet. Stress analysis in weld showed that fracture in the joint was controlled predominantly by the maximum normal stress.

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Pile foundations often used to transfer structural loads into deeper layers. On granular soils shaft resistance is an important factor bearing capacity of axially loaded, especially when the pile is subjected to tensile loading. Tensile forces apply on the pile holding the position of ship repair, basements, pumping stations, waterworks structures which are under water. In addition, transmission lines towers, tall chimneys, submerged platforms, masts, and other similar structures that are built on piles, in exposed disturbing moments resulting from wind, earthquakes and sea waves. In such structures, disturbing moments transferred, in some piles for pressure and other piles for tensile load. So, study the behavior of these piles and also effective parameters on the tensile capacity of is very important. Bearing the applied tensile loads on structures is one of the important applications of deep foundations, especially piles. Tensile capacity of these foundations is often produced by the frictional resistance in soil-pile interface. Piles are deep foundations which have considerable acceptance because of multi-applications. Understanding the behavior of piles and prediction of their tensile capacity is so important. In the last three decades various theories have been created regarding the behavior of piles under different loading conditions. The validity of these theories is evaluated by comparing the test results on models or structures piles with the predictions of theoretical. The field tests are Perfect scale and highly desirable, but often costly and difficult. For this reason, laboratory experiments are used to study the behavior of piles under tensile load. But to consider real conditions of the area, especially coastal sites, can be installed the piles in the soil that have been used to study the tensile behavior of piles. The reliability of tension test results in the homogeneous soils and the impact of surface layers of sand in providing friction force are special cases that have not been tested in real conditions of the site. Different methods are developed to achieve safe, constructible and economic design, such as analytical, experimental and in-situ methods, but in some cases they are still subjected to limitations. These methods can’t neither determine tensile capacity of pipe piles in coastal sand nor examine behavior of them. Since jacking technique is recommended for achieving improved soil properties and eliminating the deficiencies of other installation methods, so investigation of its effect is important. In this method, after jacking the piles with hydraulic jacks, the piles are arbitrarily tested under compressive loading to determine their compressive bearing capacity and then their tensile capacity is determined based on ASTM D-3689 procedure. After reading test data, the ultimate tensile capacity of piles were determined using tensile capacity criteria and then compared with analytical results. Tensile behaviors of piles at large displacements are also investigated and required force for larger pull out displacements were measured. The results showed that determined uplift capacities are more than analytical results and sand compaction due to pile installation can increase frictional resistance. It also revealed that the tangential criterion is determinant to obtain ultimate tensile capacity in most piles.

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Vibration waves with frequencies greater than 20 kHz, known as ultrasonic vibrations, are used in many manufacturing and engineering processes. This paper studies the occurrence of acoustic softening in steel specimens with three different microstructures. For this purpose, specimens with bainite and martensitic microstructures were created by Austempering and Quench heat treatments. The final dimensions of these specimens were obtained with Modal finite element analysis using ANSYS software so that the resonance frequency of the specimen is equal to the resonance frequency of transducer. Given that ultrasonic vibration induces a tension called vibrational stress to the crystal, this stress causes movement of dislocations and reduces the yield strength of specimens. In this paper 55 w / cm2 ultrasonic vibration, 18%, 12% and 8% yield strengths of specimens are reduced with ferrite- perlite, bainite and martensitic microstructure. Due to the absorption of vibrational energy by dislocation, the metal forming of these materials takes place with less energy. Also, in this paper, a numerical model for acoustic softening was investigated and it was found that there is a good correlation between numerical modeling and experimental e results.

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The main purpose of this paper is to reveal the volume effect of ultrasonic vibrations on the plastic behavior of S355J2 steel specimens with different grain sizes and investigate the decrease in the Yield strength and ultimate strength of these steel specimens. For this study, samples of grain size of 10, 35 and 60 microns were created by performing various cycles of normalization and annealing heat treatments. An experimental setup was designed and developed for the tensile test with ultrasonic vibration. The tensile test was carried out at a room temperature and constant speed of 1 mm /min and it was found that by applying 390 watts of vibrations, the yield strength reduction of steel specimens with a grain size of 10, 35 and 60 microns was 8%, 18% and 27%, respectively. . The grain boundary length in fine-grain specimens is greater than the largest-grain specimens, therefore, the sound energy is distributed over the boundary. Therefore, the effect of applying ultrasonic vibrations on fine-grain specimens is less than that of largest grains and the yield strength and ultimate strength of fine-grain specimens showed a lower reduction

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Forming limit diagrams (FLDs) are very important in predicting the behavior of the sheet. Therefore, predicting and drawing these diagrams by theoretical and experimental methods has been one of the main objectives of this paper. In this paper, the formability behavior of 5083 aluminum sheet was investigated by considering the strain hardening behavior. Tensile tests has performed in seven directions 0°, 15°, 30°, 45°, 60°, 75° and 90° from the rolling direction due to identify and calibrate coefficients of BBC2008 advanced yield criteria. The yield stresses was defined in the plane strain mode, also the anisotropy coefficients and the appropriate error function were extracted; Then the relationships of the plane strain yield stress were added to the error function. The error function was optimized using Genetic Algorithm and limit strains were calculated using yield coefficients. The results showed that if the strain hardening exponent increases by 0.1, the limit strains increase by 30 to 40%. Also the results showed that the initial imperfection factor ( ) has a great effect on determining the FLD and with a very small change, it has a great effect on the FLD; So that by increasing this factor to about 0.016, the values of the limit strains are almost doubled. Using the results of this paper and having sheet properties such as yield strengths and anisotropy coefficients and proper selection of yield criteria, the FLD of different sheets to be theoretically determined with acceptable accuracy.

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Half warm mix asphalt (H-WMA) is one of the alternatives to conventional asphalt due to its special production conditions.  Half warm mix asphalt (H-WMA) manufactured with high proportions of reclaimed asphalt pavement (RAP). Half warm mix asphalt (H-WMA) are produced and compacted at the temperature range of 60-100 ° C, which requires less temperature for production process of hot mix asphalt (HMA) for example cold mix asphalt (CMA) manufactured at a temperature lower than 60 ° C; (ii) half warm mix asphalt (H-WMA) manufactured at less than 100 ° C, normally at 60-100 ° C; (iii) warm mix asphalt (WMA) manufactured at temperatures of 100-140 ° C. The aim of this study is to investigate the effects of high percentages of reclaimed asphalt pavement (RAP) on the volumetric and mechanical properties of Half warm mix asphalt (H-WMA) mixtures. In this research, bitumen emulsion (CSS-1) and conventional bitumen 60/70 were used. The siliceous aggregates were obtained from a mine near Tehran and reclaimed asphalt pavement (RAP) were obtained from an asphalt plant and its granulation before and after extraction was done according to report number 234.  Generally speaking, in H-WMA, aggregates are heated to temperatures of 100-110 ° C and then mixed with emulsion, which has previously been heated to 60-80 ° C and RAP are heated to 90-100 ° C. To determine the most suitable mixing time in the tests, the coating was visually analyzed after mixing times of 1 and 2 min and the mixing temperature was 95-85 ° C. Thus, a laboratory analysis was carried out in which the behavior of half warm mix asphalt (H-WMA) manufactured with 100%, 70% and 0% reclaimed asphalt pavement (RAP) was compared with that of a control mix, Hot mix asphalt (HMA). Optimum bitumen content for hot asphalt mixture (HMA) and optimum bitumen emulsion content for half warm mix asphalt (H-WMA) were calculated. Then indirect tensile tests (IDT) (at 25° C), moisture damage (TSR) and Semi-Circular Bending (SCB) Tests (at 25° C and -20° C) were performed on half warm mix asphalt (H-WMA) and hot mix asphalt (HWA). indirect tensile tests (IDT) yielded acceptable results, the IDT resistance increased with increasing the reclaimed asphalt pavement (RAP) content. Following this, the moisture damage (TSR) of half warm mix asphalt (H-WMA) improves by increasing the reclaimed asphalt pavement (RAP) content, which can be due to the complete covering of the surface of the aggregates with aged bitumen and the high adhesion force between the aged bitumen and the aggregates and the lack of moisture penetration into the aggregates. emulsified bitumen exhibited proper volumetric (e.g., air voids and density) and mechanical behavior in terms of moisture damage and IDT. On the other hand, the results of SCB tests at medium and low temperatures showed that by increasing the RAP content the samples become brittle, which means that resistance to crack propagation reduced, and it may be the reason for fracture energy reduction. These findings encourage greater confidence in promoting the use of these sustainable asphalt mixes for their use in road pavements or urban streets.