Solid Mechanics Assignment Lab Report Example | Topics and Well Written Essays - 2000 words

Solid Mechanics Assignment - Lab Report Example After the model was imported to ALGOR FEA the log was checked to ensure that there were no import errors or missing geometry. Then a fixed boundary condition was applied to the internal surface of the larger cylinder after which a normal force of 500 N was applied to the internal surface of the smaller cylinder. The application of a fixed boundary condition to one area of the model meant that the model was constrained from moving within that axis of rotation or translation. The model could either rotate on the longitudinal axis of the constrained cylinder or it could translate in either three directions (x, y and z). Implementing a fixed boundary condition indicates that the model is unable to move in any direction at all. Generally a fixed boundary condition can be considered analogous to a welded piece that is unable to move but can bend or flex under applied force. Though this may not simulate the actual conditions one on one (where the crank actually rotates though it does not tr anslate at all), but it does provide a satisfactory numerical investigation model. Furthermore the application of a normal force to the other cylinder’s internal surface indicates the application of normal average force when the crank will be in use. This application of force assumes that the pin attached to the smaller cylinder of the crank will be able to transmit the applied force at the pedal completely and uniformly all across the surface of the cylinder and that this force will be normal to the provided surface. However practically this is not going to be possible as the pin will bear some kind of clearance to ensure free rotation and the clearance in turn will mean that the pin will contact the cylinder non-uniformly. Moreover the pin’s contact will produce a normal force at areas with complete contact while they will produce slightly skewed forces where the cylinder only partially contacts the subject surface. This method of applying a force to the model is non ideal yet the approximation is tolerable enough because what will take place inside the cylinder is similar. Any differences in force will not be very significant so using normal force’s application is a viable technique. The model was given a material of Steel 4130 which was present in the software’s library. After this the model was meshed using default settings. After meshing the model was simulated for calculating the developed stress and for the FOS (factor of safety) calculations. The results for the first run are shown below. The mesh was redefined for element size (which was lowered) although the mesh was still based on a 4 point Jacobian approach. The newly meshed model was then simulated in order to see the effects of a changed mesh size on the numerical investigation. The results from the re-meshed run are shown below. The results above clearly indicate that the stress distribution levels and the FOS distribution did not change at all indicating that the pr evious mesh control was providing a mesh independent solution. Therefore for the purpose of this analysis and optimisation the previous mesh controls were re-implemented as a mesh independent solution had been achieved. The results above clearly show that the lowest FOS is very high which indicates a rather overdesigned scenario. The current situation dictates that the FOS ought to be around 3:1 for a viable design. In order to achieve a more suitable FOS the design was optimised for a