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Nie R.,Tianjin University | He B.,Tianjin University | Zhang L.,Tianjin University | Li G.,China Coal Zhangjiakou Coal Mining Machinery Co.
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics | Year: 2014

This paper presents an approach to predict and evaluate the dynamic characteristics of the transmission system in conveying equipment under various working conditions. To solve the problems of varying mass and load, the space, which the transmission system locates, is divided into multiple space-fixed finite control volumes according to the material distribution as well as motion pattern. Each volume is further discretized into a series of finite elements. System-governing equations are obtained by the assembly of all the individual elements' dynamic equations and the topological structure of the transmission system. Karnopp model is utilized as the basis to render the duty resistance induced by friction. As an illustrative example, the present method is applied to model a large-scale armoured face conveyor, and the corresponding simulation code is developed based on Matlab/Simulink. Simulation results show that the start-up and stop processes with empty load are relatively smooth, which is beneficial to protect the components of the system, especially the chains. Furthermore, the resulted chain-steady velocity, chain-load spectrum and minimum tension force can be directly used to predict the conveying capacity, evaluate chain strength and optimise the pretension force. © IMechE 2014.

Nie R.,Tianjin University | He B.,Tianjin University | Yuan P.,Tianjin University | Zhang L.,Tianjin University | Li G.,China Coal Zhangjiakou Coal Mining Machinery Co.
Science China Technological Sciences | Year: 2015

An armored face conveyor (AFC) is a key piece of equipment for a fully mechanized long-wall mining system and is currently the only means for transporting bulk material in hard coal mines. To date, the AFC power train design has mainly been based on heuristics obtained via experience, coupled with simple calculations, which cannot take the dynamic behaviors and coupling effects of the components into consideration. Therefore, model-based and simulation-driven design is preferred. In this paper, a new design and analysis methodology for an AFC power train is presented to achieve the optimal dynamic characteristics and transmission performance. A preliminary design procedure for a power train is first introduced. Then, a system-level hydro-mechatronic model of the power train is built to evaluate and optimize the preliminary scheme. Sub-models, including those for the motors, fluid couplers, gearboxes, and chain, are obtained according to their individual disciplines and assembled to form the system-level model. The chain sub-system is discretized into multiple finite elements. Governing equations are established for each element based on the Newton Euler approach and assembled according to the topological structure of the chain system. In order to make the new approach applicable for engineers, a design and analysis software is developed, with a graphical user interface that involves the whole design process. MATLAB/SIMULINK is used as the computational engine, and Visual C++ is adopted to develop the interactive software framework. Simulations for the SGZ1000/2000 type AFC are provided as an illustrative case study to validate the effectiveness and practicality of the model and software package. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg

He B.,Tianjin University | Sun Y.,Tianjin University | Nie R.,Tianjin University | Li G.,China Coal Zhangjiakou Coal Mining Machinery Co.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

Armoured face conveyor is a key component of the comprehensive mechanized coal mining equipments. The ring chain transmission system is adopted to transport material from the coal face which has the characteristic of heavy duty, high power and long distance. By finite segment method and Matlab Package, the ring chain transmission system is discretized into the Kelvin-Vogit model to study its longitudinal dynamic behavior, and in the dynamic model, predefined force of the chain and two driven motor is considered. The contact model of sprocket and chains are established based on nonlinear finite element analysis via Abaqus package, and thus the stiffness coefficients of the sprocket and chain which are requisite for the dynamic model are got through the analysis. The start-up, power off and chain jam conditions of the armoured face conveyor are simulated by the model with the affects of pretension force. The minimum pretension force, dynamic tension and velocity of the chain are obtained. The methodology and simulation results help to improve the design of the machine and also offer the theoretical guide for parameter selection and match.

Zhang W.,Shenyang Ligong University | Zhong Z.,Shenyang Ligong University | Kang S.,China Coal Zhangjiakou Coal Mining Machinery Co.
International Journal of Coal Science and Technology | Year: 2015

This study was focused on wear-resistant material prepared by CO2 GMAW method to basically determine the alloys and hardfacing technology which could be employed into mining equipment. Three flux-cored wires with different chemical compositions, marked by DM-I, DM-II and DM-III were used in welding a martensitic steel for the comparison of the microstructures and mechanical properties of the welding metals and HAZ. The results show that DM-I weld metal contains martensite plus other reinforced phases, while both DM-II and DM-III alloys lead to mainly martensitic microstructures with little precipitates. Among all of the tested materials the DM-I alloy has the highest hardness and wear resistance but the lowest impact toughness among the experimental weld metals. Meanwhile, the hardness, impact toughness and wear resistance of the DM-II and DM-III alloys are close to those of the base metal but the DM-III is not as strong as DM-II. Dimples can be found on the impact fracture of the weld metals, but the steel fracture consists of both cleavage and dimples. Thus HAZ has less risk for cracking than the welds, and the DM-II wire which produces the weld having identical mechanical properties to the base metal is suitable for further application. © 2015, The Author(s).

Zhang H.,Hebei University of Technology | Zhao W.,Hebei University of Technology | Jiang P.,Hebei University of Technology | Tan R.,Hebei University of Technology | Li G.,China Coal Zhangjiakou Coal Mining Machinery Co.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

Building a product platform with rational structure is a good way for a company to obtain variety efficiently and effectively. From the aspect of design the product platform can be divided into conceptual platform and entity platform, the former forms the core resource for innovation of product family, and the latter gathers the core components for variants production. A process model for product platform design based on similarity and structural sensitivity analysis is put forward, as a solution of one of key steps, the rules and approaches for commonality design is put emphasis on. By use of that process model a more flexible product platform with hierarchy architecture can be built. According to that model the design process is separated into two phases. First, the product conceptual platform is designed based on similarity analysis and commonality design on function and conceptual structure units. Second, the product entity platform is designed based on sensitivity analysis for entity units to the changes of customer requirements. As an illustration, the process model is used for product platform design of armored face conveyer of a company. © 2012 Journal of Mechanical Engineering.

Zhang W.-Z.,China Coal Zhangjiakou Coal Mining Machinery Co.
Zhuzao/Foundry | Year: 2010

The dual circulation system is adopted in the design of water circulation system of sand temperature adjuster. The transmission medium of conventional sand temperature adjuster is changed to underground low temperature soil(earth cooling) or heating to improve the temperature adjusting ability and stability of sand temperature adjuster with the advantages of energy saving and environment protection.

Mao J.,LIAONING Technical University | Zhang Y.,LIAONING Technical University | Liu Z.-S.,China National Coal Mining Equipment Co. | Li G.-P.,China Coal Zhangjiakou Coal Mining Machinery Co. | And 2 more authors.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Horizontal clearance and vertical one between plough head and sliding framework were considered. The criterion of contact-impact between plough head and sliding framework were established with the collision detection method using the distance between a point and a line. The plough head's dynamic equation with 3-DOF vibro-impact under clearance conditions was established by using a nonlinear spring-damper contact force model. The numerical simulation was performed by using Runge-Kutta method. The results showed that there are single-point impact, two-point impact and three-point impact between plough head and sliding framework under clearance conditions; the maximum collision force at each contact point between plough head and sliding framework firstly increases and then decreases with increase in vertical clearance, and increases with increase in horizontal clearance. The plough head's dynamic model was adopted for simulation with RecurDyn. The results agreed well with those of the theoretical analysis. ©, 2015, Chinese Vibration Engineering Society. All right reserved.

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