Papers by Author: Geng Liu

Paper TitlePage

Authors: Kai Xu, Geng Liu, Xiao Zhong Deng, Jian Jun Yang, Jian Xin Su
Abstract: Planetary gear trains have many advantages in applications. In these advantages, quiet noise and slight vibration may be contribute to low Transmission Error (TE), which can be calculated by Tooth Contact Analysis (TCA). However, to obtain numerical solution of the meshing equations based on TCA for planetary gear trains is very difficult because of a large number of nonlinear equations and unknowns. A simplified method utilizing planet phase angle is investigated and the numerical solution of planetary gear trains TE by TCA can be realized in this paper.
Authors: Zheng Zhang, Geng Liu, Tian Xiang Liu
Abstract: An adaptive meshless element-free Galerkin-finite element (EFG-FE) coupling model for thermal elasto-plastic contact problems is developed to investigate the influences of the steady-state frictional heating on the contact performance of two contacting bodies. The thermal elasto-plastic contact problems using the initial stiffness method is presented. The local adaptive refinement strategy and the strain energy gradient-based error estimation for EFG-FE coupling method are combined. The adaptive meshless model takes into account the temperature variation, micro plastic flow, and the coupled thermo-elasto-plastic behavior of the materials, considering the strain-hardening property of the materials and temperature-dependent yield strength. The adaptive model is verified through the contact analysis of a cylinder with an elasto-plastic plane. The thermal effects on the contact pressure, stresses distributions with certain frictional heat inputs are studied. The results show that the accuracy of the solutions from the adaptive refinement model is satisfactory but the cost of the CPU time is much less than that for the uniform refinement calculation.
Authors: Geng Liu, Shan Chang, Li Yan Wu, Ying Sheng Li
Abstract: Planetary gear train (PGT) with herringbone gears is one of typical transmission styles used in marine power transmission. How to effectively design a PGT with lighter structures and lower vibration and noise is a fatal task for heavily loaded marine gearing. An analysis system which was developed in the past decades is introduced in this paper to simulate the performance of planetary herringbone gear trains. The effects of main crucial parameters on the static and dynamic characteristics of planetary herringbone gear trains are studied by using the analysis system. The results are discussed and show that the presented system is effective and can be used in design of planetary herringbone gear trains.
Authors: Hai Wei Wang, Geng Liu, Zhan Duo Yang
Abstract: Business process and professional simulation process are closely relative and alternate together for complex product simulation. This paper presents a business-task coupled process management method, which can implement integration management of business process and professional simulation process. Business-task coupled process is controlled by a multilayer workflow engine based on workflow technology. When the business process executes a task activity, the responding task process will be driven. The workflow engine controls every simulation activity in the task process. A simulation activity invokes one specified simulation tool and transfers data through a simulation component. The application result shows the validity of the method.
Authors: Zhao Xia He, Geng Liu, Lan Liu, Bing Han
Abstract: In order to implement collaborative work in enterprises, it is important to exchange and share data during product design process. According to the characteristics and types of simulation data for mechanical properties analysis, an effective data management method is presented. Based on the functional framework of collaborative simulation environment, a new database system has been designed by combining relational database and content repository. The content repository for simulation data has been established and designed by user-defined node type whose model is a simple hierarchy. In this repository, simulation metadata have been stored as node properties. Furthermore, simulation data files can be stored in node which facilitates the upload and download of files. In the mean while, simulation flow data can be stored in relational database. An engineering application is employed to demonstrate the feasibility and practicability of the data management system.
Authors: Shang Jun Ma, Geng Liu, Zhong Hong Bu
Abstract: A torsional and translational vibration dynamics model for serial herringbone planetary gear train, which considers the effects of the time-varying errors and meshing stiffness as well as elastic coupling between two stage trains at the same time, was established by using lumped mass method. Time domain dynamic load excitation which derived from dynamics equation is taken as the input of steady-state response solution. The steady-state response of gear structure was solved with mode superposition method combined with external judgment program. The effects of rim thickness for thin wall herringbone planetary gear and single-stage internal gear were also analyzed. Through the comparison, the displacement and stress results of key locations on structure have reached the satisfying and disirable values when the rim thickness of planetary gear is greater than 4.0 mn and rim thickness of internal gear greater than 6.5 mn.
Authors: Jian Xing Zhou, Geng Liu, Shang Jun Ma
Abstract: The dynamic load sharing characteristic of the 2K-H-type planetary gear system with floating center gear is researched in consideration of the manufacturing errors, assembly errors, time-varying mesh stiffness. The nonlinear dynamic model is set up and solved by using Newmark’s method. Then the time history of load sharing factor of the system with load balancing mechanism are obtained, and the effects of the floating clearance, the load torque, and the way of planetary gears assembled on load sharing factor are researched. The sensitivity analysis of load sharing factor is done by using finite differential method. The study provides useful theoretical guideline to the design of planetary gear system.
Authors: Qin Xie, Geng Liu, Tian Xiang Liu, Jane Q. Wang
Abstract: Reported in the paper is an elastic-plastic contact model developed to analyze the contact performance characteristics of materials with gradient yield strength. Plastic yielding and the strain-hardening properties of the materials are taken into account. The finite element method, the initial stiffness method, and a mathematical programming technique are utilized to solve the contact model. The von Mises yield criterion is used to determine the inception of plastic deformation. Results indicate that nitrided material with appropriate gradient of yield strength may greatly alter the distributions of contact stress, contact pressure as compared with untreated material in contact. The effects of different yield strength variation path of material on von Mises stress distributions are numerically investigated and discussed.
Authors: Quan Ren Zeng, Geng Liu, Lan Liu, Rui Ting Tong
Abstract: Groundbreaking work and past standard of surface integrity regarding description, measurement and evaluation of machined components are retrospected. Typical surface integrity characteristics such as surface topography, macro and microstructure, microhardness and residual stress distribution are preferentially adopted for quantitatively describing and systematically evaluating of surface integrity. Corresponding processing conditions and fatigue performance along with surface integrity characteristics are also detailedly classified and digitally defined through meaningful data sets. A framework of surface integrity model for machined components is subsequently proposed and preliminarily established by understanding the nature of surface integrity and its relation with processing parameters and fatigue properties. This pilot study offers a conceptual model as well as some feasible operational approaches for control of surface integrity in cutting technology and consequent improvement of the fatigue life for machined components.
Authors: Hai Wei Wang, Geng Liu, Dang Dang Zheng
Abstract: According to the simulation requirement for complex mechanical system, building flow modeling and control mechanism is the main content of development for the collaborative simulation platform. Based on research and analysis to WFCP-Net technique, we present multi-layer distributed flow. Management flow and simulation flow are defined, and a suit of entity class model and a kind of flow control mechanism are designed. Finally, the method is verified by the platform developed.
Showing 1 to 10 of 24 Paper Titles