Ning Wang

Bio: Ning Wang is an academic researcher from Xi'an Jiaotong University. The author has contributed to research in topics: Bearing (mechanical) & Fault (power engineering). The author has an hindex of 3, co-authored 3 publications receiving 28 citations.

Member stiffnesses and interface contact characteristics of bolted joints

Abstract: Bolted joints including bolts and members act like elastic springs under assembly and operating conditions. The bearing and transferring of the initial preload and the operating force are mainly dependent on the stiffness of both the bolts and their corresponding members. To obtain the deformation mechanism of bolted members, a systematic study on the prediction of the member stiffness and the characterization of the interface contact conditions is developed in this paper. Firstly, a parameterization process is performed to relate all the geometric dimensions of each bolted joint with the corresponding bolt diameter, so the corresponding dimensionless dimensions can be conveniently gotten by dividing the dimensions by the bolt diameter. Based on this, a novel and efficient finite element (FE) model is constructed to simulate the behaviors of bolted joints with different geometrical sizes and material properties. After characterizing the member stiffness, the interface contact characteristics of bolted joints including contact pressure and the dimensionless contact diameter are further identified through special FE post-processing efforts. Finally, a series of semi-apex angles are obtained through an inverse calculation approach in which an author-modified empirical formula is adopted. The calculation results based on the proposed method may be considered as a simple and practical guideline for the design and assembly processes of bolted joints.

Fault diagnosis based on nonlinear dynamic modeling in rolling element bearing systems

Abstract: In order to diagnose the location and size of fault in rolling element bearing system accurately, two-DOF dynamic model and six-DOF dynamic model of fault bearings are built and compared with each other based on the generation mechanism of bearing fault. The models not only consider the influencing factors of variable stiffness caused by bearing clearance, but also introduce a unit resonator to simulate high frequency inherent vibration arising with the bearing fault in sixDOF dynamic model. Dynamic models of localised fault on outer race, inner race and rolling element of rolling element bearing are simulated and analyzed by using Runge-Kutta method. The simulating results are in accordance with experimental results, which proves the accuracy and practicality of the models used in engineering application.

Resilience Analysis of Urban Rail Transit Network Under Large Passenger Flow

Abstract: Public transportation is an important system of urban passenger transport. The purpose of this article is to explore the impact of network resilience when each station of urban rail transit network was attacked by large passenger flow. Based on the capacity load model, we propose a load redistribution mechanism to simulate the passenger flow propagation after being attacked by large passenger flow. Then, taking Xi'an's rail network as an example, we study the resilience variety of the network after a node is attacked by large passenger flow. Through some attack experiments, the feasibility of the model for studying the resilience of the rail transit system is finally verified.

An Introduction to the Design and Behavior of Bolted Joints

Abstract: Although the title of this book includes the word “introduction”, the treatment of the subject is extensive and complete. The material goes well beyond the coverage of bolted joint design received in a typical undergraduate machine design course. The easy-to-read text begins with the fundamentals of bolt strength, deformation, and material selection and proceeds to cover the topics of preload, torque, and stretch control. The emphasis is on practical considerations for the efficient design of joints, including cost, ease of assembly, inspection, and disassembly. This second, revised edition has expanded the coverage of corrosion, fatigue, gaskets, and ultrasonic measurement of bolt strain. Also included are discussions of the failure modes and mechanisms of bolted joints. Case histories from industry are presented throughout the text to illustrate key points. Many up-to-date references are presented at the end of each chapter to allow the reader to pursue individual topics further, if desired. The text contains several appendices with useful tables and formulas for quick reference. The author has broad experience in the subject area from many years as a consultant to the power generation and nuclear industry, active participation on society working groups such as ASME and PVRC, as well as the presentation of numerous seminars on the topic. This book would serve as a valuable desk reference for engineers concerned with the design and performance of bolted joints.

Three-dimensional finite element analysis of the mechanical properties of helical thread connection

Abstract: Conventional analytical and numerical methods for the mechanical properties of helical threads are relied on many assumptions and approximations and thus hardly yield satisfied results. A parameterized 3D finite element model of bolted joints with real helical thread geometry is established and meshed with refined hexahedral elements. The Von Mises plasticity criterion, kinematic hardening rule of materials and interfacial contacts are employed to make it possible for the suggested model be able to approach real assembly conditions. Then, the mechanical properties of bolted joints with different thread pitches, thread numbers and modular ratios are investigated, including the contact pressure distribution at joint interfaces, the axial load distribution and stress concentration in screw threads during the loading and unloading process. Simulation results indicate that the load distribution in screw threads produced by the suggested model agrees well the results from CHEN’s photoelastic tests. In addition, an interesting phenomenon is found that tightening the bolt with a large preload first and then adjusting the clamping force by unloading can make the load distribution more uniform and reduce the maximum residual equivalent stress in thread roots by up to 40%. This research provides a simple and practical approach to constructing the 3D finite element model and predicting the mechanical properties of helical thread connection.

Influence of roller defect and coupled roller–inner–outer race defects on the performance of cylindrical roller bearing:

Abstract: In the present study, a novel mathematical model is developed for the deformation between roller and races of cylindrical roller bearing using the effect of tilting and skewing of roller due to thr...

Hybrid Models for Rotating Machinery Diagnosis and Prognosis

Abstract: The research hypothesis is that fusing the output of more than one method will improve the accuracy and precision of the remaining useful life estimation.