10-05-2012, 02:39 PM
Modeling & analysis of connecting rod of four stroke single cylinder engine for optimization of cost & material.
Modeling & analysis of connecting rod of four stroke single cylinder engine for optimization of cost & material.docx (Size: 22.72 KB / Downloads: 62)
Introduction
The main aim of the project is to determine the Von Misses stresses, Shear stresses, Maximum Principle stress, Equivalent Alternating stress, Total Deformation, Fatigue Analysis and Optimization in the existing Connecting rod. If the existing design shows the failure, then suggest the minimum design changes in the existing Connecting rod. A lot has been done and still a lot has to be done in this field. In this Project, only the static FEA of the connecting rod has been performed by the use of the software. This work can be extended to study the effect of loads on the connecting rod under dynamic conditions. Experimental stress analysis (ESA) can also be used to calculate the stresses which will provide more reasons to compare the different values obtained. Now a day a lot is being said about vibration study of mechanical component important role in its failure. So the study can be extended to the vibration analysis of the connecting rod. The study identified fatigue strength as the most significant design factor in the optimization process. Then the combination of finite element technique with the aspects of weight reduction is to be made to obtain the required design of connecting rod.
Results & Discussion
Outputs include fatigue life, damage, factor of safety, stress biaxiality, fatigue sensitivity as shown in Figures.
(1) A contour plot of available life over the model. This result can be over the whole model or scoped to a given part or surface. This result contour plot shows the available life for the given fatigue analysis. If loading is of constant amplitude, this represents the number of cycles until the part will fail due to fatigue. If loading is non-constant, this represents the number of loading blocks until failure. Thus if the given load history represents one month of loading and the life was found to be 120, the expected model life would be 120 months.
(2) A contour plot of the fatigue damage at a given design life. Fatigue damage is defined as the design life divided by the available life. This result may be scoped. The default design life may be set through the Control Panel (Table 2.1)
(3) A contour plot of the factor of safety with respect to a fatigue failure at a given design life. The maximum FS reported is 15. Like damage and life, this result may be scoped. This calculation is iterative for nonconstant amplitude loading and may substantially increase solve time (Table 2.1).
(4) A stress biaxiality contour plot over the model. As mentioned previously, material properties are uniaxial but stress results are usually multiaxial. This result gives the user some idea of the stress state over the model and how to interpret the results. Biaxiality indication is defined as the principal stress smaller in magnitude divided by the larger principal stress with the principal stress nearest zero ignored. A biaxiality of zero corresponds to uniaxial stress, a value of -1 corresponds to pure shear, and a value of 0.97 corresponds to a pure biaxial state (Table 1). From the sample biaxiality plot shown below, most of the model is under a pure shear or uniaxial stress. This is expected since a simple torque has been applied at the top of the model. When using the biaxiality plot along with the safety factor plot above, it can be seen that the most damaged point occurs at a point of nearly pure shear. Thus it would be desirable to use S-N data collected through torsional loading if available. Of course collecting experimental data under different loading conditions is cost prohibitive and not often done.
(5) A fatigue sensitivity plot. This plot shows how the fatigue results change as a function of the loading at the critical location on the model. This result may be scoped to parts or surfaces. Sensitivity may be found for life, damage, or factory of safety. The user may set the number of fill points as well as the load variation limits.