NOPR Collection:

Optimization of process parameters of wire EDM for material removal rate using Taguchi technique

Mon, 01 Aug 2016 00:00:00 GMT

Title: Optimization of process parameters of wire EDM for material removal rate using Taguchi technique Authors: Kumar, Mandeep; Singh, Hari Abstract: In this paper, the material removal rate (MRR) of Inconel X750 (Nickel based alloy) subjected to wire electrical discharge machining (WEDM) is studied and optimized by using the Taguchi technique. A 0.25 mm diameter plain brass wire is used as the tool electrode for cutting the material. Experiments are designed and conducted using Taguchi’s L-27 orthogonal array. Six input process parameters of WEDM such as spark gap voltage (SV), pulse-on time (T_ON), pulse-off time (T_OFF), wire feed rate (WF), peak current (IP) and wire tension (WT) and three interactions (T_ON*T_OFF, T_OFF*SV, T_ON*SV) are chosen as variables to study the process performance. Three trials are conducted and the average is chosen as response at that particular experimental condition. The analysis of variance (ANOVA) is carried out to determine the level of importance of the machining parameters on the MRR. Confirmation experiments are carried out to check the accuracy of the optimized results. The Investigation indicated that material removal rate increases with increase in pulse-on time and decreases with increase in pulse-off time. Page(s): 223-230

Mechanical, thermal and water absorption properties of hybrid sisal/jute fiber reinforced polymer composite

Mon, 01 Aug 2016 00:00:00 GMT

Title: Mechanical, thermal and water absorption properties of hybrid sisal/jute fiber reinforced polymer composite Authors: Gupta, M K; Srivastava, R K Abstract: In the present work, mechanical, thermal and water absorption properties of hybrid sisal/jute fiber reinforced polymer composite have been investigated. Hybrid composites are prepared by hand lay-up technique keeping constant 30 wt% of total fibers content with various weight ratios of jute and sisal fibers. Mechanical properties such as tensile, flexural and impact are investigated as per ASTM standards. Tensile and flexural test are carried out using Tinius Olsen H 10 K-L Universal Testing Machine with cross head speed of 2 mm/min. In addition, impact test is carried out using Tinius Olsen Impact 104 machine as per ASTM D 256. Thermal stability of prepared composites is obtained using Perkin Elmer TGA 4000 apparatus within temperature 30°C - 800°C in nitrogen atmosphere. Water absorption test is carried out as per ASTM D570 to obtain the maximum water uptake, sorption, diffusion and permeability coefficient. Moreover, morphological analysis is carried out to observe the fracture behavior and fiber pull out of the composite samples using scanning electron microscope. The results indicate that hybrid composite having 50% jute and 50% sisal (J50S50) has higher mechanical and thermal property and lower water absorption property than jute, sisal and other hybrid composites. For further improvement in the property of hybrid composite J50S50, alkali treatment of fibers is carried out and its positive effect is observed in terms of increase in mechanical and thermal properties and decrease in water absorption properties. The present prepared composite can be used in packaging, light weight automotive parts and construction applications. Page(s): 231-238

Fatigue life modeling of gear like products using ANN

Mon, 01 Aug 2016 00:00:00 GMT

Title: Fatigue life modeling of gear like products using ANN Authors: Ayer, Önder; Bingöl, Sedat; Altinbalik, Tahir; Kiliçgedik, Hıdır Yankı Abstract: The expected life of a gear is important parameter especially for the gears to secure of the mechanics of it. Related to this importance, fatigue failure is one of the most seen failures occurred on gears working under cyclic loads. It is not possible to eliminate fatigue failure effects but it is possible to reduce by appropriate materials selection and design criteria. Due to demand for gears with higher load-carrying capacity and increased fatigue life, it is important to determine the fatigue strengths of the gears. In this study, forward extrusion method with cosine and tapered profile dies is carried out to obtain gear-like products. The products are then tested under cyclic loads to determine the fatigue life. The results obtained from the experiments are used as inputs in developing the ANN models. Different ANN models are developed for cosine curved and straight tapered profiles to obtain the best models. A comparative analysis is performed in order to evaluate the accuracy of the developed models, in terms of statistical measurements (R2, MSE, MAE). Results revealed that proposed ANN models for both cosine curved and tapered profiles are able to predict the fatigue life of the gear-like profiles. Page(s): 239-246

Effect of interference fit size on tensile strength and fatigue life of CFRP/Ti alloy bolt joints

Mon, 01 Aug 2016 00:00:00 GMT

Title: Effect of interference fit size on tensile strength and fatigue life of CFRP/Ti alloy bolt joints Authors: Li, Jian; Zhang, Kaifu; Liu, Ping; Duan, Yuanxin; Du, Kunpeng Abstract: An experimental investigation is conducted to determine the effect of interference-fit size on tensile strength and fatigue of CFRP (carbon fiber-reinforced plastic)/Ti alloy bolted joining structure. The tensile test and fatigue experiments of interference-fit specimens are performed. The joints with four interferences-fit sizes (0%, 0.8%, 1.7% and 3.4%) are tested. The loading-displacement curves and fatigue life data of CFRP/Ti alloy bolted joints with various interference-fit sizes are obtained, and the relationship between interference-fit sizes and fatigue life are presented. The results show that the fatigue life of CFRP/Ti alloy bolted joint are associated with the size of interference fit and the dynamic stress levels, and the appropriate interference fit can improve fatigue life of CFRP/Ti alloy bolted joints compared with non-interference fit. Excessive interference fit can decrease the initial stiffness, ultimate bearing strength and fatigue life. In this paper, the joints with 1.7% interference fit have the best bearing and fatigue performances. Besides, fatigue empirical formula and fatigue damage of mechanism have been presented. Page(s): 247-253