Papers by Keyword: Crankshaft

Abstract: The crankshaft is one of the main components of the combustion engine used for continuous rotation. Therefore, this research aims to analyze the crankshaft failure of a jeep with a four-cylinder diesel engine used to transport 4 tons of logs on rugged terrain and uneven roads for 12 months. This research was carried out using the Scanning Electron Microscope (SEM), microstructure, hardness, chemical composition, and stress analysis testing methods. The chemical composition and microstructure test results showed that the crankshaft was made of AISI 3150 material with a pearlite phase. From the results of the visual observation on the fracture surface, the characteristics of failure due to fatigue are indicated by a beach mark pattern on the fracture surface. SEM test shows a crack initiation at the edge of the balancer due to the dynamic loads experienced by the crankshaft, which causes propagation from the initial beach marks pattern to the final fracture.

Abstract: The internal combustion engine is the most expensive component of a car, which determines the reliability and efficiency of its use. Studies show that one of the most common reasons for the failure of KAMAZ diesel engines during operation is the underutilization of the crankshaft resource due to wear of parts and couplings that limit its resource. An increase in the resource of crankshafts can be achieved by improving the technological processes of restoration and repair. Full utilization of the resource of KAMAZ nitrided crankshafts is possible by surfacing worn journals only after removing a nitrided layer up to 0.4 mm thick from the journals surface using specialized equipment for electrical discharge machining. Electrical discharge machining is based on the removal of material particles from the surface by an electric discharge pulse between electrodes immersed in a liquid dielectric, in the channel of which a high-temperature plasma is formed.

Abstract: The paper presents studies carried out in order to determine the causes of destruction, by cracking, of a crankshaft from the composition of a tractor used to process soil.Experiments were carried out in two directions, namely a step by step study on the degraded area and a investigation into the operating conditions of the machine, on that specific work cycle.The degraded shaft was investigated visually at a magnification of 10x and by hardness tests on the areas with embrittlement cracking.Hardness test enfolded large variations (in hardness), of up to 40%, leading to a high sensitivity to cracking by mechanical fatigue, induced by the structural tension concentrators. However, hardness examination did not reveal areas of shaft degradation due to fatigue, which determined us to study the operating conditions. The shaft cracking occurred during soil processing, using a multilayered plow and in difficult exploitation conditions.Variations of mechanical characteristics of soils in the area of ​​operation of the machine, is relatively large, fact which corroborated with the lack of safety elements when overloaded, of the endowment of the tractor-plow system, led to the overcoming of the permissible load, which on a background of high hardness material, determined the embrittlement cracking of the crankshaft. Research performed highlighted, for the area in which the machine activates, the necessity of introducing in the power-generating system of safety and protection elements to prevent the destruction of components.

Abstract: Aiming at realizing the coordination deformation of crankshaft-bearing system for engine, the equation of coordination deformation for crankshaft-bearing system was derived based on the theory of elasticity. According to the hydrodynamic lubrication theory, the mathematical model was established to analyze the bearing characteristics; the displacement of each bearing in the vertical direction was calculated by combined solution of the two parts above. The sum of squared differences of displacements was evaluated as evaluation standard of coordination deformation for crankshaft-bearing system. Then bearing clearances were chosen as optimized variables of crankshaft coordination deformation for the optimization. The crankshaft-bearing system of one type of engine was optimized for the coordination deformation. The results indicate that the optimization scheme of crankshaft-bearing system can make a significant improvement to coordination deformation and provide reference for the design of the engine.

Abstract: Engine operating conditions of the main propulsion, static in principle with steady-state rotation speed of the crankshaft and engine load, also work under dynamic load conditions. These conditions cause additional distortion of the crankshaft and changes in the operating conditions of the shaft bearings. However, the greatest impact on the long and trouble-free operation has proper engine maintenance. Variable operating conditions and engine operating errors, unfortunately, often cause damage to the main bearings of the crankshaft. Repair of the damaged main bearing spindles of the shaft involves performing the machining of the spindle surface then its re-hardening and selecting new bearing bushings with the appropriate bearing clearance. Trusting the engine manufacturer, there is no check of the influence of the machining of bearing spindles on the structural properties of the shaft. Therefore, the paper presents the model tests of the structure of medium-rev marine engine crankshaft aimed at determining the changes in the mechanical properties of the structure resulting from carrying out the regeneration of the main shaft spindles.

Abstract: In this study, the influence of workrest positions on the deflection of a crankshaft is investigated, in order to enhance the machining precision in orbital grinding. Crankshafts of 3m, 5m and 8m are selected, and three types of states (no machining, journal machining and pin machining) are studied. The model is simplified with stiffnesses applied to the stock instead of real contact between workrest and stock. As the workrests are positioned to the machining region, the deflection of the machined stock is reduced. Pin machining shows more stable result than journal machining.

Abstract: The paper uses the preprocessor of ANSYS to generate the model of 3D entity and mesh generation on WW0.8/10 air compressor crankshaft. Mesh generators are transferred into data that will be used in finite element analysis. Passing by dealing with force and commitment, it calculates the forces of pressure working conditions of crankshaft. They are used in stress analysis. The stress data is calculated from the calculator of ANSYS. The static load safe coefficient and the fatigue safe coefficient of the crankshaft are tested from known stress. The result provides a high reference value for the optimization improvement of the crankshaft.

Abstract: Cold shearing machine is the machine equipment often used in metallurgical industry to shear head, tail and fixed length of rolled piece. The shearing movement of cold shearing machine can be realized by crankshaft driving link rod with relative up-and-down motion. Load on crankshaft is comparatively big. In this paper, cold shearing machine crankshaft was taken as an example. The three dimensional model of relative cold shearing machine crankshaft was constructed by SolidWorks software. Strength finite element analyses on relative model were made by static analysis module attached to SolidWorks software under maximum load working conditions. The overall displacement distribution pictures and overall Von Mises stress distribution pictures of cold shearing machine crankshaft under relative load working conditions were obtained. This research provides important reference base for the design and reform of cold shearing machine crankshaft.

Abstract: Aim at the bending and upsetting process of a kind of crankshaft, this paper analyze the technical difficulty and treatment measures during the process. The metal flowing and the defects easily occur during the deformation are visual reappeared by the FEM, moreover, the influence of the thickness of flash and the size of fillet on the quality of crank is also analyzed. Takes the crank as an object, the experiment of bending and upsetting deformation is carried on, which verified the accuracy of the simulation result, and finally, the crank is qualified with fullness deformation, continuous fiber without collapsing or folding. The product with this process can satisfied all the specification of the technology.

Abstract: Compressive residual stresses and high hardness introduced by induction quenching are often used to improve the mechanical performance of crankshafts in engines. In this paper, in order to predict the fatigue strength of the crankshafts in a diesel engine accurately, the quenching process and the stress fields of the crankshaft are simulated by finite element method (FEM) and then the residual stresses are obtained. Quenching is a high non-linear process because of the coupling of the temperature, phase transformation and stress/strain fields. The transient temperature field is firstly solved using a quasi-coupling method to simulate the relationship of the temperature and the phase transformation. Based on the results of the temperature and phase transformation fields, the thermo-elastic-plastic analysis is then carried out to calculate the stress fields including the thermal stresses and the phase transformation stresses. At last the residual stress distribution at the room temperature is obtained.