Non conventional method proposal for residual stress simulation generated by end milling process
Author
André Luiz Rocha D'Oliveira
Advisor
- Advisor Alfredo Rocha de Faria
Concentration Area
Mecânica dos Sólidos e Estruturas
Defense Date
08/07/2016
Thesis Number
71858
Abstract
Surface integrity can be considered as a parameter that is most studied due to its effects on the product performance. The relationship between the functionality and manufacturing variable effects has been mapped, mainly associated with machining process. This process is focused on the connection among the thermo-mechanical loads generated during the process and the residual stresses induced by them. For that reason, industries that have the machining process as the base of the manufacturing chain are naturally interested in these investigations. Additionally, sustainable practices have been put in place, such that for cost reduction, loss reduction and environmental adjustments, optimization of the machining process is demanded. Therefore, validation of functional integrity is more and more required. As experimental procedures are time consuming, alternative computational methods are considered, but only inefficient approaches for complex machining operations are available. Thus, there is need to propose new and efficient one possibility, based on the finite element method, is a hybrid approach for complex machining processes. This approach can be described as the direct application of the machining loads in the workpiece without the necessity of modelling the interaction between tool and workpiece. However, that method was just tested for simple cases of machining, and the application for a more complex process has not been tried yet. Therefore, this work proposes the application of the hybrid method in the end-milling process. This approach resulted in substantial reduction of time for solving the model (from days to hours) with the desired outcomes (residual stress field). The challenges associated with this method were identified as load measurements and the application of these loads, and also the correct definition of the boundary conditions. Another point that was observed is that the residual stress field can be computed without the obligation to apply the loads in the finished shape. That fact renders the machining process easier to model. Finally, even with the simplification of the model, the possibility to expand for other machining processes was confirmed.
