Applied Mechanics and Materials Vol. 577

Abstract: In order to reduce the wheel-rail wear and improve the safety and comfort of the vehicle during the running round the curve section, in this paper, based on the theory of vehicle dynamics and by the dynamics software-SIMPACK, it created a model on the relationship of wheel-rail. It conducted research on the three situation include deficient superelevation, normal superelecation and surplus superelevation when the train crossing the curves. It analysed the change regulation about the two parameters which are rate of wheel load reduction and overturning coefficient during running of the train. Most importantly, it analysed deeply about the regulation of the change about wear power and wear number accompanied by the change of superelevation. Two main conclusions were made in this paper. The first one is wear number and the changes of superelevation are negatively correlated. The second one is wear power and it is positively correlated. It suggested us that it should be in lower when the train crossing the curves. It should use lower deficient superelevation when it can’t in the case of the best situation.

Abstract: Thermal expansion of ball screw system affects the machining accuracy of machine tools significantly. The objective of this paper is to analyze the thermal behavior and predict the temperature variation pattern of a ball screw based on finite element analysis and experimental investigation. Wireless temperature sensors are used to monitor the temperature variation of the ball screw system under different thermal conditions during both the warm-up and cooldown phases, so as to investigate its temperature variation pattern. Then an exponential algorithm is proposed to analyze and predict the temperature variation of the ball screw based on finite element analysis, and the actual thermal boundary conditions of the ball screw system are exactly defined according to the proposed algorithm and the experimental results. Finally, it was found that the simulation based on the thermal boundary conditions identified herein could match quite well with the experimental results.

Abstract: Nowadays, as a result of the serious shortage of parking spaces in major city all over China, people often feel it’s difficult to park their cars. Building mechanical parking garage has become an important way to solve this problem. Lifting and sliding mechanical parking garage is the most widely used mechanical parking garage. At present, lifting and sliding mechanical parking garage widely adopts centralized control system based on PLC. But there are several disadvantages in this kind of control system, suck as structural complexity, weak expansibility, and high cost. With the advantages of simple structure, strong expansibility, low cost and high reliability, CAN bus control system is widely used in the mechanical parking garage. The major mission of this paper is to study the control system of lifting and sliding mechanical parking garage based on CAN bus.

Abstract: In nuclear power plants, the steam generator heat transfer tube is the weakest part of the primary circuit pressure boundary. Flow induced vibration is one of the main reasons for the failure of the heat transfer tube. In this paper, an ANSYS finite element software is used to carry out the modal analysis of the heat transfer tube, and to simulate the dynamic response of the heat transfer tube in the harmonic load based on the modal analysis.

Abstract: High-strength steel pipes have excellent strength but have poor fracture arrest. By finite-element analysis involving fluid-structure interaction (FSI) method, models of high-strength steel pipe with three kinds of defects (triangle, rectangle and semi-ellipse) were built to determine the concentrated stress based on the working conditions of X70 pipelines in the West-to-East Natural Gas Transmission Project, and the simulation results were compared with the field test results measured by an X-ray stress analyzer. With the same defect width (2 mm), the triangular defect (40°) had a greater influence on the concentrated stress in the pipe than rectangular and semi-elliptic defects. The results can be taken as references of the damage failure process of the defect in pipes in operating conditions as well as a theoretical basis for the fracture arrest of pipes in field operation.

Abstract: The paper established the accurately 3D-modeling of the gear by I-DEAS, and had correlative theoretic analysis and finite element computing technology study on its dynamics meshing structure strength with the contact finite element method. Then, accomplish model studied gear-stress in the process of Gear Drive. The conclusion is used to design an upgrade similar straight gear.

Abstract: In this paper, the Xiali car Mcpherson type front suspension lower arm as the main research object, research the Xiali car converted to electric vehicles, the lower arm, internal stress distribution of structure on the lower arm, and on the basis of optimization design is carried out with ANSYS software. The last judgment andevaluation of prototype vehicle and electric vehicle arm stress, strain distribution and variation of structure on the lower arm, the topology optimization analysis is carried out, the lower arm to meet the strength and stiffness of the structure at the same time, meet the requirements of lightweight design.

Abstract: Hydraulic press occur elastic deformations in the working status. The deformation will affect the precision of the products. This paper expounds the method of using Laser tracker test rigidity of THP11-10000A isothermal forging hydraulic press. And we test the deformation of the lower bean, fit the date and compare with fitting of the finite element simulation results. The validity and the accuracy of the simulation results are verified.

Abstract: Half power method is commonly used in structural damping identification because of its simplicity in algorithm. But when the damping is very small, half power method will lead a big error. In order to get more accurate result of small damping structure, this paper suggests using negative ten decibels method (N-10dB) instead of half power method. N-10dB method takes 10-dB bandwidth into consideration, differs from 3-dB of half-power method. The theory of this method is given firstly and proves that it is very simple in algorithm. Subsequent simulation and experiment show that, compared with half power method, N-10dB method have stronger noise resistance, higer precision and is more stable in repeated measurements. Except that, the N-10dB method is also practical in engineering test.

Abstract: Combining with both working condition of working roll in tension leveler and wear classification, this paper maintains that abrasive wear is the main type of working roll’s abrasion, and states that shape defects of hot rolled strip is the main cause of the abnormal abrasion of working roll, and concludes that to reduce the wear of working roll relying solely on technology of tension leveling has its limits. So, combining with the materials of working roll in tension leveler and rolling mill, the surface hardness and the wear rates of different materials after heat treatment are experimentally analyzed to provide a theoretical guidance for the further improvement of working roll’s materials.