WEAR FAILURE MECHANISM AND MULTI-IMPACT PROPERTY OF AUTOMOTIVE ENGINE CHAIN

The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.

Teaching Experiment in Engineering Mechanics Based on Simulation Technology:A Case Study

This paper explores the integration of simulation technology in Engineering Mechanics(EM)teaching in vocational colleges.A case study was conducted using the tensile test as an example,and digital resources,such as colored Mises stress nephograms,were obtained.These resources were integrated into the original curriculum to conduct teaching experiments.The results show that the use of digital resources significantly improved the quality of teaching in EM.The integration of simulation technology in EM teaching provides a promising direction for the improvement of vocational education and the cultivation of high-quality skilled talents.The development and application of more simulation-based teaching cases should be studied by scholars.

Application Strategies of BIM Technology in Highway Electromechanical Engineering

The transportation system is vital for social and economic development.With the rapid economic development,the demand for highways has been increasing.Mechanical and electrical engineering is a crucial part of highway construction,affecting the expressway’s later use.Applying building information modeling(BIM)technology in highway electromechanical engineering allows for the visibility and simulation of mechanical and electrical engineering construction,providing scientific guidance for construction.In this research,the author analyzes the advantages of BIM technology in highway electromechanical engineering and the basic composition of electromechanical engineering.The research proposes strategies and cases for applying BIM technology in highway electromechanical engineering.The ultimate goal of this research is to improve the construction of highways in terms of electromechanical engineering.

Reform of the Comprehensive Practical Course System for Mechanical and Electronic Engineering Majors Under the Background of New Engineering

Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.

Review of Power Supply and Distribution Construction Technology for Highway Electromechanical Engineering

In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.

Interactive Training Model of TRIZ for Mechanical Engineers in China

Abstract： Innovation is a process of taking an original idea and converting it into a business value, in which the engineers face some inventive problems which can be solved hardly by experience. TRIZ, as a new theory for companies in China, provides both conceptual and procedural knowledge for finding and solving inventive problems. Because the government plays a leading role in the diffusion of TRIZ, too many companies from different industries are waiting to be trained, but the quantity of the trainers mastering TRIZ is incompatible with that requirement. In this context, to improve the training effect, an interactive training model of TRIZ for the mechanical engineers in China is developed and the implementation in the form of training classes is carried out. The training process is divided into 6 phases as follows： selecting engineers, training stage-l, finding problems, training stage-2, finding solutions and summing up. The government, TRIZ institutions and companies to join the programs interact during the process. The government initiates and monitors a project in form of a training class of TRIZ and selects companies to join the programs. Each selected companies choose a few engineers to join the class and supervises the training result. The TRIZ institutions design the training courses and carry out training curriculum. With the beginning of the class, an effective communication channel is established by means of interview, discussion face to face, E-mail, QQ and so on. After two years training practices, the results show that innovative abilities of the engineers to join and pass the final examinations increased distinctly, and most of companies joined the training class have taken congnizance of the power of TRIZ for product innovation. This research proposes an interactive training model of TRIZ for mechanical engineers in China to expedite the knowledge diffusion of TRIZ.

Deformation mechanism of roadways in deep soft rock at Hegang Xing’an Coal Mine

Engineering geomechanics characteristics of roadways in deep soft rock at Hegang Xing'an Coal Mine were studied and the nature of clay minerals of roadway surrounding rock was analyzed. This paper is to solve the technical problems of high stress and the difficulty in supporting the coal mine, and provide a rule for the support design. Results show that mechanical deformation mechanisms of deep soft rock roadway at Xing'an Coal Mine is of ⅠABⅡABCⅢABCD type, consisting of molecular water absorption (the ⅠAB -type), the tectonic stress type + gravity deformation type + hydraulic type (the ⅡABC -type), and the ⅢABCD -type with fault, weak intercalation and bedding formation. According to the compound mechanical deformation mechanisms, the corresponding mechanical control measures and conversion technologies were proposed, and these technologies have been successfully applied in roadway supporting practice in deep soft rock at Xing'an Coal Mine with good effect. Xing'an Coal Mine has the deepest burial depth in China, with its overburden ranging from Mesozoic Jurassic coal-forming to now. The results of the research can be used as guidance in the design of roadway support in soft rock.

EXPERIMENTAL STUDY ON HIGH-SPEED CHARACTERISTICS OF AUTOMOTIVE ENGINE OIL-PUMP CHAIN

The high-speed multi-cycle impact and speed, load fluctuant characteristics of a kind of narrow-width automotive engine oil-pump chain 06BN-1 are studied through engine assembly and road-drive tests to satisfy the light-weight demand of engine. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine oil-pump chain is fatigue wear, and it＇s failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. Pin and bush both occurred cycle-soften phenomenon, and roller occurred cycle-harden. Fretting wear is one of the most important ＂fall to pieces＂ failure causes of automotive chain. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technology are the effective methods to increase its resistance to multi-cycle impact.

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686,CN 11-2187/TH

Cooperative Reconfiguration for a Reconfigurable Mobile Robot LIU Tonglin, WU Chengdong, LI Bin, LIU Jinguo （1. State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China; 2. Graduate School, Chinese Academy of Sciences, Beijing 100049, China; 3. School of Information Science ＆ Engineering, Northeast University, Shenyang 110004, China）Abstract： A main characteristic of the reconfigurable mobile robot AMOEBA-1 is that it has diverse configurations, but some reconfigurations are difficult to realize under the influence of ground conditions. A cooperative reconfiguration method is proposed to reduce reconfiguration resistance and enhance the adaptability of the robot to the environment. The mathematical model is established correspondingly. The kinematics and mechanical properties of each section of the robot are analyzed. A part of resistance is transformed into active force of reconfiguration, and transforms are actualized among five specific configurations. Further, the linearization of model based on a perturbation analysis method is used to reduce the computational complexity. Finally, an evaluation criterion is proposed for AMOEBA-I＇s cooperative reconfiguration performance. The validity of the cooperative reconfiguration method is proved by simulations and experiments.

Engineering rock mechanics practices in the underground powerhouse at JinpingⅠhydropower station

Based on the analyses of data obtained from the underground powerhouse at Jinping I hydropower station, a comprehensive review of engineering rock mechanics practice in the underground powerhouse is first conducted. The distribution of strata, lithology, and initial geo-stress, the excavation process and corresponding rock mass support measures, the deformation and failure characteristics of the surrounding rock mass, the stress characteristics of anchorage structures in the cavern complex, and numerical simulations of surrounding rock mass stability and anchor support performance are presented. The results indicate that the underground powerhouse of Jinping I hydropower station is characterized by high to extremely high geo-stresses during rock excavation. Excessive surrounding rock mass deformation and high stress of anchorage structures, surrounding rock mass unloading damage, and local cracking failure of surrounding rock masses, etc., are mainly caused by rock mass excavation. Deformations of surrounding rock masses and stresses in anchorage structures here are larger than those found elsewhere： 20% of extensometers in the main powerhouse record more than 50 mm with the maximum at around 250 mm observed in the downstream sidewall of the transformer hall. There are about 25% of the anchor bolts having recorded stresses of more than 200 MPa. Jinping I hydropower plant is the first to have an underground powerhouse construction conducted in host rocks under extremely high geo-stress conditions, with the ratio of rock mass strength to geo-stress of less than 2.0. The results can provide a reference to underground powerhouse construction in similar geological conditions.

Recent advances of digitization in rock mechanics and rock engineering

In recent years, there are growing demands of representing rock mechanics and rock engineering in a digital format that can be easily managed, manipulated, analyzed and shared. The objective of this paper is to give a comprehensive review of the status quo and future trends of digitization in rock mechanics and rock engineering. Research topics essential to the process of digitization are firstly discussed, including data acquisition, data standardization, geological modeling, visualization and digital-numerical integration. New techniques that will play an important role in digitization process but require further improvement are then briefly proposed. Finally, achievements of present methods and techniques for digitization in substantial rock mechanics and rock engineering are presented.

MODELING AND IMPLEMENTATION OF SPEED GOVERNOR FOR THE HYBRID ELECTRIC VEHICLE ENGINE

A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.

Application of Parametric Design to Mechanical Engineering

The definition and functions of parametric design were introduced. According to the practical condition of mechanical engineering design, the necessity and feasibility of parametric design for complex mechanical engineering design was analyzed. The related key technologies and methods were also discussed by a project example based on Inventor platform.

ENGINEERING MECHANICS AND MATERIALS RESEARCH IN THE INFORMATION TECHNOLOGY AGE

In this paper, importance of information technology research and development for economic growth and prosperity is presented. Major missio of the research for fundamental science and engineering base is discussed. Critical points of the mechanics and materials research in the 21st Century are proposed.

Contents and Abstracts of Chinese Journal of Mechanical Engineering(Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Vol.44,No.3,2008 Investigation into Mechanism of Initial Rail Corrugation Formation at a Curved Track JIN Xuesong WEN Zefeng XIAO Xinbiao (Traction Power State Key Laboratory,Southwest Jiaotong University, Chengdu 610031,China) The mechanism of initial rail corrugation formation at a curved track is analyzed with a numerical method.The numerical method consid- ers a combination of a coupling dynamic model of a half railway vehicle and a finite length curved track, Kalker′s theory of three-dimensional elastic bodies in rolling contact,and a material wear model,The Hertzian contact non-linear spring with a unilateral restrain and the non-linear tan- gent creep-force model by SHEN-Elkins-Hydrick are used to couple the vehicle model with the track model.Through the detailed analysis on the dynamic behavior of the vehicle curving and the transient contact geome- try of the wheelset and track,the normal forces,the creepases,the contact point positions,and the contact geometry parameters of the wheels and the rails are obtained.According to the known numerical results the

Contents and Abstracts of Chinese Journal of Mechanical Engineering(Chinese Edition),ISSN 0577-6686,CN 11-2187/TH Vol.44,No.5,2008

Vol.44,No.3,2008 Investigation into Mechanism of Initial Rail Corrugation Formation at a Curved Track JIN Xuesong WEN Zefeng XIAO Xinbiao (Traction Power State Key Laboratory,Southwest Jiaotong University, Chengdu 610031,China) The mechanism of initial rail corrugation formation at a curved track is analyzed with a numerical method.The numerical method consid- ers a combination of a coupling dynamic model of a half railway vehicle and a finite length curved track, Kalker′s theory of three-dimensional elastic bodies in rolling contact,and a material wear model,The Hertzian contact non-linear spring with a unilateral restrain and the non-linear tan- gent creep-force model by SHEN-Elkins-Hydrick are used to couple the vehicle model with the track model.Through the detailed analysis on the dynamic behavior of the vehicle curving and the transient contact geome- try of the wheelset and track,the normal forces,the creepases,the contact point positions,and the contact geometry parameters of the wheels and the rails are obtained.According to the known numerical results the rolling

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Vol.43,No.7,2007 NOVEL RECOATING PROCESS WITH DYNAMIC OPTIMIZED BLADE SPEED XU Guangshen ZHAO Wanhua LU Bingheng (1.Department of Mechanical Engineering, Xi’an Polytechnic University,Xi’an 710048,China; 2.Institute of Advanced Manufacturing Technology, Xi’an Jiaotong University,Xi’an 710049,China) In order to improve the recoating quality of piston recoating system and resolve the problem that resin layer thickness increases with the height of object during building process in high-resolution stereolitho- graphy system,a novel recoating process whose blade speed is dynami- cally optimized during building process is proposed.Experiments are carried out to investigate the influence of blade speed and object height on the thickness of resin layer.The mathematical model describing the rela- tionship of recoating layer thickness with object height and blade speed is

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Research on Categorizing Innovation of Speed Reducers,Optimization Algorithm for Robotic Belt Surface Grinding Process,Design and Viscoelasticity Dynamics Modeling of Flexible Driven Unit for Robot＇s Joint