In this study, for the first time, thermoplastic polyurethane granule (TPU) is used as a reinforcing phase and self-healing agent in a polymer composite epoxy resin (ER) to exhibit mechanical properties recovery. When the polymer composite is damaged or cracked, TPU granules are released at the site of damage and cause auto-repair of surfaces. Therefore, TPU granules with different composition percentages were mixed in silicon molds containing epoxy resin polymer composite. 4 samples with different TPU granules percentages were selected (A= 0 Wt.% TPU, B=10 Wt.% TPU, C=20 Wt.% TPU, and D=30Wt.% TPU). At first, making a deep cut in 4 polymer composite samples, the self-healing process and mechanical properties improvement are investigated by mechanical tests. In the self-repairing behavior of self-healing samples, it is observed that polymer composite samples with self-repairing agents of ER+20 Wt.% TPU granules had the highest self-healing efficiency (60.2%) compared to other specimens. A mechanical test shows that Sample C has a higher Young’s modulus (4.837 MPa) and higher tensile strength (9.46 MPa). Also, the impact test illustrated Sample C has a higher impact energy of 7.1 (J/m). Therefore, sample C has the highest mechanical properties among self-healing samples. تفاصيل المقالة

Gas turbine disks usually operate at very high temperatures and rotate at very high angular velocities under normal working conditions. High temperature in turbine disks causes changes in their properties. High angular velocity creates a large centrifugal force in the disk and high temperature reduces the strength of the material and causes deformation. Complexity of these parameters has turned the determination of stress distribution in gas turbine disks to one of the bottlenecks in the analysis, design and manufacturing of turbine engines. Therefore, using an applicable method for stress analysis is essential in order to better determine stress distribution in turbine disks. In this study, the finite element method (FEA) is used for predicting the behavior of rotating disks under mechanical and thermal stresses. In order to increase the certainty of simulation, gas turbine disk is first simulated and analyzed based on dimensions and loading conditions extracted from previous studies. Then, the results are compared with previous studies in order to determine the accuracy of analysis method applied in ANAQUS software. Afterwards, gas turbine disks are evaluated under both rotational movement and temperature gradient. The results show that the presence of angular velocity and centrifugal force cause expansion to the disk radius. The results show an acceptable correlation between the results of empirical and numerical studies. According to the results, the approach proposed in this study is a suitable method for analysis of the stress, temperature and displacement in turbine disks and other components with similar functions. تفاصيل المقالة