Finite Element Analysis on Vacuum Pump Assembly Components under Extreme Thermal Conditions 2012-28-0018

As India is becoming a hub for design and manufacture of various automotive parts for the global market, it becomes important to verify whether the design is safe at extreme thermal operating conditions, before the introduction of the product to market. For our current work, we have identified Vacuum Pumps, which are principally used in diesel applications for generating vacuum primarily for the servo brake application. With the emission norms getting modified, EGR and turbo charging are employed to meet them. The vacuum signal is used for EGR actuation, turbo charger waste gate actuation, etc. The multi functional application of vacuum pumps and the functional criticality in application like braking system demand an efficient and reliable performance.

Finite element analysis (FEA) is one such tool, which can be used to verify the product/components for structural and thermal rigidity at different operating conditions. In our present work, we have carried out the analysis for predicting the stresses to check whether the values are within allowable limits at extreme operating conditions. We have also studied the clearance analysis of the product in order to check interferences between various components.

The material properties of each component at extreme temperatures of vacuum pump were assigned to the corresponding finite element model. The material properties for ferrous and non-ferrous components were taken from the material library. For parts like rubber and plastic materials, which are non-linear in nature, samples were tested and results fed as input for analysis. Suitable algorithm was used to create connectivity between various parts based on the nature of each connection. The solver was chosen for the analysis by considering the type of analysis, the degrees of freedom and the hardware configuration. Non-linear analysis was carried out for estimating the stress and clearances, which depend on the behavior of material, geometry and presence of contact elements.

Numerical analysis helped in visualizing the stress contours in the vacuum pump assembly and helped in predicting the high stress regions of the selected material and design. Design tolerances were verified for clearances between moving parts, in critical areas, due to variation in temperature. Finite Element Analysis results gave good insight on the design and material selection for use under extreme thermal limits.