Numerical and Experimental Investigations On Cross-sensitivity Characteristics of Instrumented Wheelset Associated with Longitudinal Force and Lateral Contact Position

It is crucial to grasp wheel-rail contact forces in the evaluation of running safety and curving performance of railway vehicles. To measure the wheel-rail contact forces, instrumented wheelset, which has the strain gauges on the wheel surface, is widely used. The purpose of this research is to increase the measurement accuracy of the wheel-rail contact forces by understanding the detailed characteristics of the instrumented wheelset. Although the various research works on the instrumented wheelset have been carried out to increase the measurement accuracy of wheel-rail contact forces, there are few works considering the longitudinal force and the lateral shift of the wheel-rail contact point. However, sometimes the longitudinal force has a non-negligible influence on the measurement accuracy on the instrumented wheelset. In this paper, the authors clarify the cross-sensitivity characteristics of the instrumented wheelset when the longitudinal force is applied to the various lateral position on the wheel tread through the FEM analysis and the static load test. The authors also propose a method to approximate the cross-sensitivity as an analytical function of the lateral and circumferential contact positions.

FEM ANALYSIS OF ENERGY LOSS DUE TO WAVE PROPAGATION FOR MICRO-PARTICLE IMPACTING SUBSTRATE WITH HIGH VELOCITIES

The impact between particles and material surface is a micro-scaled physical phenomenon found in various technological processes and in the study of the mechanical properties of materials. Design of materials with desired properties is a challenging issue for most industries. And especially in aviation one of the most important factors is mass. Recently with the innovations in 3D printing technologies, the importance of this phenomenon has increased. Numerical simulation of multi-particle systems is based on considering binary interactions; therefore, a simplified but as much accurate as possible particle interaction model is required for simulations. Particular cases of axisymmetric particle to substrate contact is modelled at select impact velocities and using different layer thicknesses. When modelling the particle impact at high contact velocity, a substrate thickness dependent change in the restitution coefficient was observed. This change happens is due to elastic waves and is important both to coating and 3D printing technologies when building layers of different properties materials.

Methodology of Teaching Methods of FEM Analysis Using Software ANSYS

This paper presents the authors' experience of teaching the finite element method (FEM) at university. With the development of computational tools in the second half of the twentieth century, there was also the development of computational methods focused on the algorithmization of engineering tasks based on FEM. From the solution of individual problems of the state of stress and deformation from the influence of the external environment, a complex solution of the mutual interaction of the system of deformable bodies (elements) has been performed while improving the physical and geometric characteristics of modern materials and structures. Many processes in the automatic design system take place as if in a "black box" and the process of verifying the achieved results becomes the most important stage in the design activity. Without knowledge of the theoretical basis of FEM, physical and mathematical modeling, verification procedures and methods, the design of a structure cannot be safe and reliable. In this paper we present one of the possibilities how the student can get acquainted with the theoretical foundations of FEM and with computational procedures using ANSYS software.

Design and Analysis Considering Magnet Usage of Permanent Magnet Synchronous Generator Using Analytical Method

In this study, the characteristic analysis of a permanent magnet synchronous generator was performed using the analytical method, and the validity of the analytical method was compared with that of the finite element method (FEM). For the initial design, the rotor size was selected using the torque per rotor volume method, and the stator size was selected according to the saturation of the stator iron core. In addition, fast Fourier transform analysis was performed to determine the appropriate magnet thickness point, and it was confirmed that the open circuit and armature reaction magnetic flux densities were consistent with the FEM analysis results. Based on the analytical method, the generator circuit constants (phase resistance, back EMF, and inductance) were derived to construct an equivalent circuit. By applying the equivalent circuit method to the derived circuit constants, the accuracy of the equivalent circuit method was confirmed by comparing the FEM and experimental results.

Stresses and deformations of an osteosynthesis plate in a lateral tibia plateau fracture

This study has the aim to investigate the strain and stress in an anterolateral locking plate applied for the fixation of a lateral split fracture. To simulate a complex fracture situation, three segments were separated. With a FEM analysis, representative places for strain and stress measurement were determined. A locked osteosynthesis plate was instrumented with strain gauges and tested on a fractured and a non-fractured Saw Bone model. To simulate different loading situations, four different points of force application, from the center of the condyles to a 15 mm posterior position, were used with a medial-lateral load distribution of 60:40. The simulations as well as the biomechanical tests demonstrated that two deformations dominate the load on the plate: a bending into posterior direction and a bulging of the plate head. Shifting the point of application to the posterior direction resulted in increasing maximum stress, from 1.16 to 6.32 MPa (FEM analysis) and from 3.04 to 7.00 MPa (biomechanical study), respectively. Furthermore, the comparison of the non-fractured and fractured models showed an increase in maximum stress by the factor 2.06–2.2 (biomechanical investigation) and 1.5–3.3 (FEM analysis), respectively.

Analysis of the Working Performance of a Back-to-Back Geosynthetic-Reinforced Soil Wall

Back-to-back geosynthetic-reinforced soil walls (BBGRSWs) are commonly used in embankments approaching bridges and narrow spaces. However, the available literature and design guidelines for BBGRSWs are limited. The aims of this research were to develop a greater understanding of the working performance of BBGRSWs and to optimize the design method of a BBGRSW to ensure the cost-efficiency as well as the stability of the structure. On the basis of a monitored BBGRSW structure located in China, we established a numerical model. The parameters of the materials used in the actual project were determined through triaxial and tensile tests. The numerical results were compared with the measured results in the field to verify the correctness of the selected parameters. Two parameters were investigated by the FEM method: the reinforcement length and the arrangement. The FEM analysis indicated that post-construction deformations such as displacement and settlement could be reduced by reinforcing the same layer on both sides. Longer reinforcements were needed to achieve the same performance if the reinforcements were cross-arranged. Thus, BBGRSWs can have a superior performance if the reinforcements are connected in the middle from both sides. Even with longer reinforcements, the safety factor of the wall with a cross-arranged reinforcement was smaller than that with same-layered reinforcements.

DESIGN AND STRENGTH ANALYSIS OF A CRANE HOOK WITH A 500 KG LIFTING CAPACITY

A bridge crane is a type of crane that is designed for lifting / lowering and transferring material in the horizontal direction and is used mainly in production halls, warehouses and transship points. A part of the lifting mechanism of the bridge crane is a crane hook on which the load is suspended. Sufficient strength is required from the crane hook in order to be able to withstand high loads relatively well. The most stressed part of the crane hook is the curved inner surface. This surface is considered critical in terms of strength. The goal of this paper is to select a suitable crane hook for a single girder bridge crane with a load capacity of 500 kg and a strength analysis of the selected crane hook. Strength analysis is performed by two methods, first is based on analytical calculation and second is based on finite element method (FEM) performed in Ansys software. The comparison of the obtained total stresses from both methods is the part of the analysis. From the results of the FEM analysis and analytical calculation it can be stated that the selected crane hook RSN 05 P - DIN 15401 with a load capacity of 500 kg is suitable for the above-mentioned bridge crane. It can also be concluded that the total stress determined by the analytical calculation is lower by 9.8 % compared to the stress obtained from the Ansys software.

Python-Based Open-Source Electro-Mechanical Co-Optimization System for MEMS Inertial Sensors

The surge in fabrication techniques for micro- and nanodevices gave room to rapid growth in these technologies and a never-ending range of possible applications emerged. These new products significantly improve human life, however, the evolution in the design, simulation and optimization process of said products did not observe a similarly rapid growth. It became thus clear that the performance of micro- and nanodevices would benefit from significant improvements in this area. This work presents a novel methodology for electro-mechanical co-optimization of micro-electromechanical systems (MEMS) inertial sensors. The developed software tool comprises geometry design, finite element method (FEM) analysis, damping calculation, electronic domain simulation, and a genetic algorithm (GA) optimization process. It allows for a facilitated system-level MEMS design flow, in which electrical and mechanical domains communicate with each other to achieve an optimized system performance. To demonstrate the efficacy of the methodology, an open-loop capacitive MEMS accelerometer and an open-loop Coriolis vibratory MEMS gyroscope were simulated and optimized—these devices saw a sensitivity improvement of 193.77% and 420.9%, respectively, in comparison to their original state.