A new method (thermal spokes) is proposed to simulate the GUIDE ROLLS in FE analysis of the ring rolling process. So far this method is the only one, capable of calculating GUIDE ROLLS reaction contact forces related to the stiffness of their, adjustment mechanism. The method is simple to use, does not introduce further nonlinearities and could be used in any kind of FE formulations. The method is successfully employed in FE analysis of rectangular and T-section rings. The results of the thermal spokes method, a new analytical method based on lever arm principle with experimental results are in good agreements. This analysis shows that the GUIDE ROLLS greatly affect the process.

Background: Enteral nutrition through a Naso-Gastric (NG) tube is a technique often used for hospitalized patients who have problems with oral nutrition. It can reduce patients mortality and morbidity if be performed correctly. Several methods are used to reduce risk of misplacement of the tube. In present study, we suggest a type of GUIDE wire for correct placement of NG tubes.Methods: It was a clinical trial study carried out in operation room of Al-Zahra hospital, Isfahan, on 60 patients. After abdominal incision, NG tube was placed using GUIDE wire in first group (n=30) and without it in second group (n=30). Patients’ profiles, times of trial for tube placement, as well as complications were completely registered and analyzed by SPSS (ver.13).Findings: Mean age of patients was 44.9 years (rang: 18-60). The results show that the mean of trials in first group was 1.26, compared with 2.13  in second group (P-value: 0.011). Seven patients in first group and 11 patients in second group confronted with early complications during performing the procedure. These complications were tube entrapment in nasopharynx (16% in first group and 20% in second group), epistaxis (3% in both groups), and revolving of the tube (3% in first group and 13% in second group) (P-value>0.05).Conclusion: It seems that use of GUIDE wire for placing the NG tube lead to lower misplacement of the device and may reduce the risk of further complications.

The main purpose of this article is calculating forces and moments of each of the process ROLLS for designing and manufacturing of ring rolling machine to be used for airplane engine cases. Axial redial ring rolling process was simulated by finite element method. To validate the results, output of simulation of rolling a simple ring made of Ti-6Al-4V alloy was compared to experimental results. Comparing results show good accuracy of simulation. Also in this article, a new method for simulating of GUIDE ROLLS proposed, that is more simple and efficient than the previous methods.

The application of high-pressure grinding ROLLS (HPGR) in iron ore processing is expanding. However, to maximize their utilization, it is crucial to understand the impact of various parameters on their operation, given their advanced technology. Wear is an essential factor that needs to be considered when operating these mills. Failure to manage wear can lead to substantial costs and a decline in machine efficiency, as well as the efficiency of the comminution circuit. Therefore, it is imperative to control the wear rate of ROLLS by adjusting the machine accordingly. This research aims to measure the wear pattern of HPGR ROLLS in the primary grinding circuit of the Sanabad Iron Beneficiation Plant in Iran. The results indicated that the wear rate of the studs along the ROLLS was not uniform but rather concave, and the maximum wear rate was observed in the central part of the ROLLS. The wear rate of the studs on the fixed roll was higher than that of the floating roll. For the current mill, the predicted useful life of the ROLLS was estimated to be between 12000-13000 hours, considering the operating time of 8000 hours of the current HPGR.

Pipes with non-circular cross sections made by reshaping processes are widely used as structural elements in almost all industries. Despite a long history of the process, because of the complicated deformation behavior of pipes during reshaping, the design procedures for forming ROLLS and pass-schedules mainly rely on experience-based knowledge. Thus, the fundamental and systematic approaches to the reshaping technology and the guidance for the design of ROLLS and processes have been required. In order to solve these serious problems, a new design method has been developed to determine ideal roll profiles and roll arrangement for the process. It is based on the simulation technique to analyze twodimensional elasto-plastic deformations of the cross sections of pipes. Furthermore, it is shown that there are good agreements between the results of the design method and the experimental results for the square and the oval pipes.

Ring rolling process is used in the production of seamless rings. The most important advantages of these rings are favorable grain flow and crack growth resistance. Aircraft engine spools are usually produced by means of this process. Failure of the work ROLLS during forming of spools leads to unacceptable microstructure, geometrical structural and irreparable damages. Evaluation of the work ROLLS conditions of the ring rolling machine has a direct effect on the geometrical and mechanical properties of the output ring. By making use of Abaqus simulation, the loading history was extracted and applied to the work ROLLS. According to the loading history, stress-life method and cumulative damage relations were performed. The main-roll is significantly affected by mechanical stresses. On the other hand, the mandrel is affected by thermal stresses. In general, the proper cooling has a significant effect on the service life of the mandrel. In addition, the effect of bending stresses on the mandrel’ s life is not significant. The results of the research show that the responses of the work ROLLS to thermo-mechanical loads are completely different. The probability of damage and crack initiation due to thermo-mechanical loads in the main-roll and mandrel are below and on the work ROLLS surface, respectively.

Generally, in pipe manufacturing industries, roll design, in the cold roll forming process, is performed, based upon experiments and the qualitative choice of the designer. In this paper, a computer program is provided to reduce the number of qualitative decisions. In this research, ROLLS are designed, based on the Kiuchi method, using a sine shape function. Elasto-plastic analysis is done for determining the 3D shape of strips, strain, stress distribution and the consumed roll power between roll stands. Then, by equalizing the power for all roll stands, the ROLLS are designed. Finally, considering the technological parameters of the process and the dimensions of the machines, a SCRIPT file for manufacturing the ROLLS is prepared for the user. Using the results of the point test, based on CAD/CAM principals, it is shown that the results of the provided computer program, for the 3D shape of the strips, are consistent with experimental data.