Papers by Keyword: Crankshaft

Abstract: crankshaft is one of the most important parts and crankshaft fatigue fracture is a major failure. In order to alert fatigue fracture of crankshaft to prevent accidents, diesel engine crankshaft dynamic monitoring based on the actual situations of diesel engines, significance of dynamic balance for marine diesel engine crankshaft system is discussed and as well vibration monitoring and field dynamic balance system for diesel engine crankshaft system is constructed. The least square method is applied to fit fundamental frequency vibration signals of crankshaft system and the field dynamic balance strategy is designed on the basis of the influence coefficient method. The feasibility of the dynamic balance system is tested through experiments in the paper.

Abstract: In the process of calculating the crankshaft frequency and vibration mode, free mode is always applied for the crankshaft modal analysis. Considering the effect of centrifugal force generated by the rotation to the crankshaft frequency and vibration mode, the frequency and vibration mode of multi-speed cases are calculated, and compared, which fully shows the vibration situation of the crankshaft in the process of actual working situations, the results match actual situation.

Abstract: Fracture is the most common failure modes of the crankshaft, under normal circumstances often result in serious consequences. So study the reasons for the crankshaft fracture, thus achieving the purpose of controlling and reducing accidents, is very realistic. In this paper, for example, a factory break 4M16 compressor crankshaft. Through micro-analysis of the crankshaft fracture, the 4M16 compressor crankshaft is a low stress fracture of brittle fracture .The fracture is mainly due to dendritic segregation cause tissue caused by uneven. Solution to the problem is to increase the ratio of forging the forging, heat treatment when the grain refinement.

Abstract: Taking a grinding machine tool as an example, this paper obtained the static stiffness of the machine tool by finite element analysis method. The structure and technical parameters of the machine tool were introduced at first.Then, the finite element model of the machine tool was established. The static stiffness of the machine tool in x-, y-, and z-directions were simulated at last. The results show that, the static stiffness in x-direction is 2.0062×10⁷ N/m, the static stiffness in y-direction is 0.821×10⁷ N/m, and the static stiffness in z-direction is 0.2992×10⁷ N/m. This paper provides advices for structure optimization of the machine tool which is convenient for improving the machining accuracy.

Abstract: Considering the effect of centrifugal force generated by the rotation to the crankshaft frequency and vibration mode, the frequency and vibration mode of multi-speed cases are calculated. The results showed that the impact of the centrifugal force on the crankshaft vibration increases with the increase of rotational speed, especially in the high speed region, this phenomenon is more obvious. From low speed to high speed, the vibration frequency has a large deviation, which shows that in this case, it is necessary to consider the frequency change caused by pre-stress.

Abstract: At present, crankshafts with larger size are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not meet design and use request. So horizontal spindle barrel finishing has been developed and has good finishing effects for crankshafts with small size. But this process has bad uniformity for connecting rod journal of crankshafts with larger size by simulation experiments. Aimed at the size, shape and weight of crankshafts with larger size, theoretic research is done, and main factors for finishing uniformity are analyzed. Finally its finishing project is defined and experiments are done. The research indicates that this process is very effective for crankshafts with larger size, and has also positive influence on efficiency and auto product line.

Abstract: Crankshaft is one of the important parts of reciprocating compressor. It takes a large reciprocating compressor crankshaft as the research object. First it establishes the three-dimensional solid model of the crankshaft by the software Pro/E. Then it contacts the Pro/E and ANSYS Workbench by the interface to establish the finite element model of the crankshaft. After taking the modal analysis and calculations of the crankshaft in the ANSYS Workbench module, it obtains the foundation for the design of the crankshaft structure.

Abstract: Based on the theories of induction heating and thermal conductivity, and by establishing a three-dimensional finite element analysis model including the induction coil, crank cheek and air, the pattern of temperatures field distribution and thermal deformation condition of the crank cheek during the period of induction heating were numerically simulated with software ANSYS. The simulation result showed that, by setting a circular coil inside the crank cheek, a uniform temperatures field around the hole would be obtained after a certain period of induction heating. As a result, the crankshaft would reach a high quality shrinkage fitting, manifesting the feasibility of the application of induction heating to the crankshaft shrinkage fitting.

Abstract: The failures of the crankshafts are constantly subjected to cyclic loading which will tend to display the effects of fatigue that is stochastic in nature. The maximum bending moment occurs during the combustion cycle, where the direction of forces acting on the crankshaft will be exactly towards the centre of the crank radius. The torsional stress occurs during the power cycle can be considered as a quasi-static torsion as it is in steady condition. The aim of this paper is to illustrate the development of the analytical stress analysis used to determine mixed mode loading acting on the crankshaft. The analytical method developed according to the geometric ratio of the connecting rod and crankpin web to determine the variation of bending moment and torsional stress. It was observed that the maximum bending moment and torsional stress acting on the crankshaft are at angles and respectively due to the geometric ratio of the connecting rod and crankpin web. The analytical method that was derived and used for this study provides a good accuracy in determining the critical angles for bending moment and torsional stress acting on the crankshaft based on the geometric ratio.

Abstract: Crankshaft is one of the most important parts in diesel engine. The fatigue failure and fracture of crankshaft may lead to damage to the other parts, even some accidents. Recently with the increasing requirement of engine power and engine reliability, the investigation of the crankshaft strength becomes more important. Since during the engine work process, the extremely complicated force are loaded on the crankshaft and different vibration caused by torque, bending, etc., the crankshaft may create the resonance and appended dynamic stress in the working frequency range, which will be easy to bring about the bending and torsion damage after short work period. In this paper, the traditional algorithm on the basis of MATLAB/SIMULINK software is used to carry out the dynamic calculation and analysis for a certain type of diesel engine crankshaft. The crankshaft stress state and its variation are analyzed, and the results of the bending moment, torsion versus crank angle are obtained. Finally, the fatigue strength of crankshaft is checked and the safety factor is calculated to verify the crankshaft reliability.