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Pipes are mainly used in waste, drain and vent systems as well as transporting various liquids that might be corrosive, flammable, explosives, volatile, reactive, or sometimes hazardous to human health. Though pipes are used at the underground or above ground, all of them are exposed to vibration because of external factors. In this study, we focused on topology optimization of steel and PVC (Polyvinyl Chloride) pipes to get lighter ones which will lead to using less material during manufacturing, less CO2 emission while transporting them to usage areas by vehicles and easier assembling process. Firstly, new lightweight pipe designs were modeled, and then these novel pipe designs with lattice wall thickness were analyzed by using Ansys finite element program in clamped-free, hinged-hinged, and clamped-clamped boundary conditions to obtain the natural frequencies, mode shapes, and displacement values. Moreover, obtained finite element results for steel and PVC pipes were compared with analytical results calculated by using the equation to check and compare with the finite element results. Finite element results were found similar to analytical results at an acceptable level. The results show that lightweight pipes have similar natural frequency values to the commonly used pipe which has fully solid wall thickness and some significant results about displacement values were attained. Lastly, the effect of pipe material on vibration behaviors of pipes was investigated in depth. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tool steel is a widely used material in forming and manufacturing of injection molds / equipments. Injection and forming dies are subjected to repetitive high pressure and heat during operation, which leads to unexpected formation of cracks in the die. In case of continuation of continuous and repeated loads, starting crack causes the die lose its function or stopping injection process. In this study, a series of finite element analyzes and optical investigations have been carried out to determine the cause of the damage of 1.2367 hot work tool steel injection gate brush which has lost its function as a result of repetitive mechanical and thermal loading, and the design of the injection gate brush has been changed to prevent this damage. As a result of new designing of injection gate brush, a decrease in stresses of gate brush under working was observed. Hereby, the strength of injection gate brush was improved. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The using areas of composite materials in mainly aerospace sector and other industry have been increased due to their more light, high fatigue strength, impact strength and specific strength properties than metals. The critical factor in fiber reinforced laminate composites from composite materials is to crack formation on interface matrix structure and fibers carrying loads and distributing forces to matrix structure. Also, the cracks on interface matrix structure and fibers cause decreasing the composite structure strength with crack propagations under loads. In this study, the effect of location and angle of the crack in the laminate hybrid composite material reinforced with glass-epoxy, boron-epoxy, carbon-epoxy, glass-boron-carbon-epoxy fibers at different angles on mechanical behaviors is determined with finite element analyses. In analyses, the different located crack and crack angles (0° and 30°) inside the laminate composite structure with different fiber materials reinforced at different angles (0°, 15°, 30°, 45°, 60°, 75° and 90°) with 1.5 mm of total composite thickness were formed and applied tensile forces. Afterwards, stress and displacement values were obtained in the cracked fiber reinforced structures. According to results, Decrease in stress at top and bottom aluminium plate was observed in case of parallel fiber orientation to the applied forces. Beside, shear stresses increase with increasing the crack angle. [ABSTRACT FROM AUTHOR]

Today's manufacturing sector has introduced to a manufacturing method depending on developments in materials, engineering software and laser technologies which are combined to manufacture as a useful engineering part of 3-D digital design by layer upon layer from polymer, metal, ceramic materials. This method has entered into the literature as "Additive Manufacturing" and today it has been used in mainly medical, automotive, space-airplane, computer and home appliances sectors and also prototypes of parts with specific and complex geometries and / or make it possible to produce a useful engineering part. In this study, the studies conducted in the area of modern manufacturing science were evaluated and the point reached in 3-B additive manufacturing, additive manufacturing methods and application areas were investigated and it was tried to give information that could be projected to our manufacturing sectors. [ABSTRACT FROM AUTHOR]

In product development and improvement, Computer Aided Engineering (CAE) provides decreasing of the continuously prototype manufacture and product costs and increasing the product quality. Generally, CAE applications are carried out with analysis and simulations of prototype design. Forexample, cooler plates used in automobile, electronic, manufacturing and energy sectors are manufactured after analyzed by FEM In this study, as different from literature, the effect of fin face geometry, number of fin and its thickness, material type of plate on heat transfer are characterized by finite element modelling (FEM). Aluminum and copper plate materials are chosen in FEM and finite element model was set to analyze heat transfer performances of cooler plate with different three fin number (4, 6, 8 number of fin), different two fin face geometry (straight and waved), then FE model was solved by exposing three different temperatures (50 °C, 150 °C, 250 °C) to cooler plate. The heat transfer rate and temperature gradient (Δt) values on cooler plate were obtained by FEM analyses. As a result, some information are obtained for cooler plate applications of electronic devices, manufacturing and energy systems and automobile parts. [ABSTRACT FROM AUTHOR]

Titanium in industrial applications has been described as costly material and difficult to manufacture. But, Ti alloys have been commonly used in aerospace constructions and implant production because of its specific properties. Machining difficulties are taken place incase of the manufacturing of Ti alloys by casting method. Powder metallurgy method for part production from Ti alloys is preferred for minimizing of production costs and machining difficulties. For this aim, Ti-6Al-4V, Ti-5Al-2,5Fe and Ti-6Al-7Nb alloys using in biomaterials and aerospace industries were produced from elemental powders by pressing at 530 MPa and sintering at 1250°C temperature at protective argon gas atmosphere under 10-4 torr vacuumed. Pores structure, sinter neck formation, and widmanstatten structures were investigated experimentally. In order to determine of effect of the pores structure on wear and bending strength, wear and bending tests were performed. As a result, bigger porous and lower sinter neck formation of Ti-6Al-7Nb alloy than other Ti alloys decreased the wear strength and bending strength. [ABSTRACT FROM AUTHOR]

In this study, wear performance of cast copper alloyed with ferromanganese powder was determined by wear experiments. Surface of the specimens produced by cast copper were alloyed with 9 g ferromanganese powders using 115 A, 125 A and 140 A current intensities applied by Gas Tungsten Arc (GTA) Method. Wear experiments were carried out using different loads 20, 40 and 60 and sliding distances. The wear characteristics were measured with weight loss. Fuzzy logic model was setup according to experimental results. Current intensity, applied load and sliding distances were assigned as inputs and then wear amount was designed as output in this fuzzy logic model. Based on experimental results, system input and output membership functions were determined. Output support range was investigated in eight groups to be able to make sensitive estimates. It is found that estimated wear amount with the use of the proposed system be very close to experimental wear results thanks to regration analyses (R2 correlation values). For untested conditions wear performance characteristics could be determined with an application of the proposed fuzzy logic model of the investigated alloys. [ABSTRACT FROM AUTHOR]

In this study, cutting force of circular diamond saw in marble cutting industry was modeled using fuzzy logic method. Different cutting forces are effective during cutting processes and saw is damaged by these forces. Monitoring and controlling of the forces is important for cutting machine and circular diamond saw life and its influence the work-piece quality. Monitoring of cutting forces during cutting process can be provided with an expert and electronic system. According to literature experimental studies in fuzzy model, the specific removal rate, depth of cut and feed rate were assigned as input values and cutting force was designed as out value. Most convenient membership functions and support range were selected for each input-output parameter. Relations between memberships functions were established according to expert knowledge obtained from the literature experimental results. Cutting force values were predicted according to input values in the fuzzy model. Fuzzy model was verified by predict value which was compared with the literature experimental value. As a result, output values obtained from fuzzy system were compatible with experimental results and it was exposed that cutting forces were estimated without marble cutting tests. [ABSTRACT FROM AUTHOR]