f. morshedsolouk

In cement production, rotary kilns are essential, particularly in clinker manufacturing. The spring plates, fabricated from St37-2 steel, connect the girth gear to the kiln shell and play a crucial role in the structural integrity of the kiln. This study numerically analyzes and optimizes the stress distribution across spring plates used in the Kufa cement plant (Najaf, Iraq), under varying operational conditions. Using finite element modeling (ANSYS 2022/R1), stress distributions for the standard spring plate design (S), three existing designs (d1, d2, d3), and three proposed designs (P1, P2, P3) were compared. Sensitivity analysis was conducted across five filling conditions: (1) 100% design load, (2) 100% practical load, (3) 90% practical load, (4) 80% practical load, and (5) 70% practical load. The proposed P3 design demonstrated the best performance, reducing the maximum stress concentration at critical locations by 51.86% compared to the standard design, with maximum stress values of 154.06 MPa (P3) versus 320.08 MPa (S) under 100% design load. The sensitivity analysis confirmed that stress levels decreased with reduced kiln loads, enhancing the service life of the spring plates. This study underscores the importance of design modifications to minimize stress concentration and improve the operational durability of rotary kilns.

Twisted and coiled polymer actuators (TCPAs), typically made from fishing lines or sewing threads, became increasingly popular across various applications due to their unique capacity to contract or twist when heated, mimicking the behavior of artificial muscles. Their performance can be highly variable due to some manufacturing factors like fishing lines diameter. The study investigates TCPAs' mechanical behavior, considering changes in the diameters of fishing lines, operating temperatures, and applied tensile forces. For this purpose, this study addresses these challenges by experimenting with TCPAs of different diameters (0.5, 0.7, and 0.8 mm), using a hot water circulation system to control actuator temperature, enabling rapid and consistent actuation. Testing TCPAs under various thermal conditions reveals that both displacement and tensile strokes increase with temperature and decrease with tensile force. Also, the TCPA with a 0.7 mm diameter which has the smallest coil spring index and the smallest coil bias angle achieved the best performance, with a maximum displacement of 17 mm and a tensile stroke of 7.65% at 80°C and 1.422 N. These findings provide a clear pathway for creating reliable, high-performing TCPAs, making them suitable for applications requiring precise and consistent actuation.

Glass fiber-reinforced plastics (GFRPs) have been widely used in marine structures, recently. In this paper, the water absorption and compressive behaviour of pultruded fiber-reinforced plastic pipes (GFRPs) after immersion in Caspian sea water and distilled water for 1, 7, 14, 21, 28, 35, and 40 days is experimentally investigated. In this respect, the specimens are submerged in Caspian seawater and distilled water and then their water absorption rate, length, and their compressive strength were measured every day. The compressive mechanical properties of the specimens in the as-received and water-aged states are obtained using quasi-static compression tests. The amount of water absorption and length change due to immersion in these two cases have also been investigated. After 40 days, the average relative humidity absorption of the samples in Caspian Sea water and distilled water were 2.88% and 2.89%, respectively. It was observed that after immersion in both Caspian Sea water and distilled water, the final compressive strength and absorbed energy of the pultruded pipes increased.

This paper investigates the quasi-static compressive strength of two sandwich structure designs in which cores consist of trapezoidal corrugated panels. In one design, the core consists of a steel cross-corrugated two-layered structure, while in the other design, the core consists of a single layer of bidirectional interconnected corrugated core made of ST37 steel sheets. To investigate the energy absorption capacity of these sandwich structures quasi-static compression is performed numerically and experimentally. First, from each design, a test specimen is constructed and tested under quasi-staticcompressive load. Following that, the finite element models of the designs are constructed and their crushing process is simulated and the FEM method results were compared with the test results and the FE model is verified. After verification of the numerical model, for each design, three different trapezoidal wave profiles are modeled and, the mechanical behavior of the other bidirectional interconnected corrugated cores is evaluated numerically. The results showed that the maximum force and energy absorption capacity of the sandwich structures with the single-layered bi-directional interconnected corrugated core is higher than the strength and energy absorption capacity of their counterparts with the same weight in the two-layered bi-directional corrugated core group with the same weight. It was also found that, inthe single-layered bi-directional interconnected corrugated core group, the failure mode is plasticity near the welding joints, while for the single-layered bi-directional interconnected corrugated core, the failure mode is plastic buckling of the corrugated core under compressive load and some local plastic deformation in the connection of the layers.