Capstone project

Study of the reliability of finite-element models in the design of cast stainless steel pump parts : the development and testing of a finite-element model of a pump bracket

The objective of the project was to check the feasibility of using finite-element models in the design of cast stainless steel pump parts. A finite-element model of a centrifugal pump bracket (Price Pump Company part number 4010) intended to be used to couple a centrifugal pump volute to an electric motor was developed using the Aegis WeCan and CAEFEM software. Because the bracket could not be perfectly divided into regularly shaped finite-elements, certain approximations in the geometry of the bracket were made in developing the finite-element model. A large part of the objective of the project was to find out whether such approximations significantly reduced the reliability of finite-element models. The computer model was subjected to loads which simulated the effects of thermal expansion of the pump piping when the bracket was being used to couple a volute with an electric motor. An actual pump bracket was subjected to the same loads as the model so that I could verify the stresses calculated by the computer model. The stresses at various locations on the actual bracket were calculated based on strain gage measurements. The stresses measured on the actual part very closely matched the stresses on the computer model. The greatest percent error was 13.3%. The average percent error was 6.4%. The small inconsistency between the model and the actual part were due to differences in the way by which the model and the real bracket were constrained and not due to inaccuracies in the structure of the finite-element model. The results showed that the stress calculations of the model were accurate.

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