Fatigue Life Of Crankshaft Research Articles

COMSOL-based fatigue simulation of crankshaft

The crankshaft is the most valuable and precise single component of the automobile engine, and the force of the crankshaft is extremely complex. It works under the combined action of periodic changes of gas pressure, reciprocating inertia force, and torque, and bears huge bending and torsional alternating loads. It is of great significance to study the effects of bending, torsional, and compound loads on the strength and fatigue life of crankshaft. In this paper, a crankshaft simulation model is established according to the fatigue reliability theory, the fatigue reliability of the crankshaft is determined, the fatigue life is analyzed, the stress-strain simulation of the crankshaft is carried out by COMSOL, and the fatigue load spectrum and damage cloud map of the crankshaft are obtained. The results show that the structural parameter that has the greatest influence on the stress and deformation of the transition rounded radius. The position corresponds to the place of the crank pin where maximum stress occurs.

Fatigue life analysis model of crankshaft under uncertain working conditions based on physical-data collaboration

The uncertainty of working conditions often affects the fatigue life of the crankshaft. In order to study the impact of uncertain working conditions on the fatigue life of the crankshaft, the fatigue life analysis model of crankshaft under uncertain working conditions was established based on the engine working process model, equivalent stress calculation model, fatigue life calculation model and surrogate model. The engine working process model was established based on the filling and empty method to simulate engine performance under different working conditions, and the accuracy of the model is verified by experimental data. The equivalent stress calculation model under uncertain working conditions was established by combining the performance data with the equivalent stress calculation model. Based on the fatigue life curve, the transformation from equivalent stress to fatigue life can be realized, and the fatigue life of crankshaft under uncertain working conditions can be obtained. Finally, the relationship model between working condition and fatigue life was established based on the Kriging surrogate model. Through comparative analysis, the calculation errors of the established equivalent stress calculation model and fatigue life calculation model are 2.6% and 1.9% respectively. This study not only establishes the relationship between fatigue life and working conditions of crankshaft based on physical-data collaboration, but also provides an effective model basis for follow-up crankshaft reliability analysis.

Analysis of dynamic fatigue characteristics of critical parts of highly strengthened single cylinder diesel engine

In this paper, the strength analysis and fatigue life calculation of multi-component coupling of crankshaft, connecting rod and engine body of highly strengthened single cylinder diesel engine are carried out. The stress of crankshaft, connecting rod and engine body in two working cycles is calculated by multi-component coupling transient dynamics, and the strength is analyzed based on the third strength theory firstly; Then, the accuracy of the transient calculation results is verified by the strength experiment of the crankshaft and connecting rod reduced scale model and the calculation of the static stress of the body; Finally, according to the stress fatigue life calculation method, the fatigue life of crankshaft, connecting rod and engine body is calculated. The maximum stress of crankshaft, connecting rod and body is less than the yield limit of corresponding materials; The fatigue life calculation results show that the damage accumulation of the engine body is very little, which meets the design requirements of infinite life. The damage accumulation of the crankshaft at the fillet of the main journal and the connecting rod at the side of the rod is 32005.6 hours and 102841.7 hours respectively, which meeting the design requirements of 20000 hours.

DYNAMIC STRUCTURAL ANALYSIS OF ENGINE CRANKSHAFT AT DIFFERENT ANGLE OF CRANK TURNS FOR THREE DIFFERENT MATERIALS

For many years, engines have been one of the main power machinery of different kinds of applications, and the main part of power machinery is a crankshaft that converts the piston’s reciprocating displacement with four-link mechanisms into rotary motion. . The major limitation of the engine crankshaft is fatigue failure due to repeated load caused by bending and torsional load. In this paper, the comparative dynamics structural analysis was carried out for three different materials such as forged steel, cast iron, and chromium-molybdenum steel with different angles of turns of cranks from 0° to 720° and to predict the stresses, deformation, and fatigue life of crankshaft without compromising its weight, strength and reliability. The 3D CAD model was simulated with FEA software. The simulated results show that by applying bending load and torsional load for three materials, the maximum stresses produced in the fillet area of the main bearing journal and in the fillet area of the crankpin journal at a crank angle of 360° respectively. The deformation results revealed that maximum deformation occurs at the mid-surface of the crankpin. From fatigue life prediction it was observed that forged steel and chromium-molybdenum steel shows better fatigue life as compared to cast iron. Moreover, in the comparative study, it was concluded that chromium-molybdenum steel shows fewer stresses and better fatigue life. Therefore it is suggested that chromium-molybdenum steel would be the better option for manufacturing crankshaft.

Study on Failure Analysis of Crankshaft Using Finite Element Analysis

Crankshaft is one of the crucial parts for the internal combustion engine which required effective and precise working. In this study, the aim of the study is to identify the stress state in the crankshaft and to explain the failure in automotive crankshaft and fatigue life of crankshaft by using finite element analysis. The 3D solid modelling of the crankshaft model was designed and developed using SolidWorks. A static structural and dynamic analysis on an L-twin cylinder crankshaft were used to determine the maximum equivalent stress and total deformation at critical locations of the crankshaft. The model was tested under dynamic loading conditions to determine fatigue life, safety factor, equivalent alternating stress and damage using the fatigue tool. The results obtained from this study indicated that the crankshaft has obvious fatigue crack which was belongs to fatigue fracture. The fatigue fracture developed was only attributed to the propagating and initiate cracks on the edges of the lubrication hole under cyclic bending and torsion. Overall, the crankshaft is safe for both static and fatigue loadings. In dynamic analysis, the critical frequency obtained in the frequency response curve should be avoided which it may cause failure of the crankshaft.

Modal and Harmonic Analysis of Crankshaft for High-Power Drilling Pump

The crankshaft is very important in high-power drilling pump. The information on the vibration mode and frequency response is critical for the crankshaft to work normally in drilling pump. ANSYS finite element analysis software was used to implement the modal analysis of the crankshaft thus obtaining characteristic frequency and the corresponding vibration mode and then by the harmonic response analysis which was carried out based on the modal analysis, dynamic response of the crankshaft was obtained. The result shows that the working speed of crankshaft can avoid the region of sympathetic vibration effectively, no resonance will happen. The strength and fatigue life of crankshaft are also checked according to the stress results. The analysis also makes a base for the optimized design of dynamic performance of the crankshaft.

Study on Local Strain Field Intensity Approach for Prediction Fatigue Life of Crankshaft Based on Mechanical Mechanics

The bending fatigue limit moment and crack initiation life of 4105 crankishaft in five groups of bending moments are obtained by resonant bending fatigue tests first. Then, the static finite element calculation using sub-model is performed to get the strain distributions in every test load. The results show that in the region where stress concentrate, the strain field could be seen as plane strain state. So two dimensional strain field intensity model is selected. In order to remove the influences of size and surface conditions, the radius of strain field is determined with the strain distribution under the low-life test load. After that, the local strain field intensities under each test load are calculated with the radius of strain field. Finally, the strain-life curve of material is modified by the fatigue intensity limit of crankshaft, and the predicted life agree with the test results.